THE COACH IS ON THE ROAD. THE APP IS IN THE GYM, OR THE OFFICE, OR THE STADIUM, OR….

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I am somewhere between Salt Lake City and Omaha, with my Golden Retriever pup Ellie in her crate in the back with approximately 2,000 miles still ahead of us.

I’m behind the wheel for 7-10 hours a day. So the real Coach Keir is unavailable this week. He is driving, hydrating, eating cans of tuna and soup (yep, this is a thing with me), and listening to audiobooks about ultra-processed food (also a thing with me) while Ellie sleeps soundly in between pit stops (thankfully, this is a thing with her).

The AI Coach Keir, however, has not taken a single day off.

When I have a moment to check in on the app’s backend, this week I’ve been watching athletes I normally train with in person open The Slowfit Method® app, describe whatever equipment they have in front of them, and get complete, detailed, coaching-cued workouts back in seconds. No appointment. No Zoom link. No waiting for me to get off the highway.

Here’s what that looks like in practice.

Foghorn Fitness is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

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Bob was at a track in San Francisco with stadium steps and a jump rope.

He asked for a 30-minute circuit with some push-ups or burpees. This is what Coach Keir AI gave him:

Warm-up (5 minutes): 2 minutes easy jump rope, World’s Greatest Stretch x5 per side, Hip 90/90 for 60 seconds, thoracic rotation x5 per side, leg swings front/back and side to side x10 each.

The circuit (20 minutes, 4 rounds, 60-90 seconds rest between rounds): Jump rope 60 seconds at moderate pace, stadium steps — run or power-walk up, walk down (one full trip), push-ups 10-15 reps full range chest to ground, burpees 5 reps quality over speed with full extension at the top, stadium steps — second trip up, walk down.

A legitimate Foghorn workout. Stadium steps, bodyweight, jump rope. No gym required.

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Chris had a jump rope and a 30lb sandbell.

He asked for a HIIT workout. Coach Keir AI named it the Foghorn HIIT — Rope and Sandbell and built him this:

4 rounds, approximately 30 minutes, 60 seconds rest between rounds.

Jump rope for 60 seconds, sandbell slam for 10 reps, jump rope for 45 seconds, sandbell clean and press for 8 reps, jump rope for 30 seconds, sandbell rotational lunge for 6 reps each side.

The coaching cues were specific: for the sandbell slam, drive it down from overhead with the whole body — hinge, load the hips, reach to the sky, then throw it at the ground. For the clean and press, it is one fluid movement, not three separate ones. For the rotational lunge, step into it, rotate the sandbell across the lead knee at the bottom — Weck Method rotational power, head over foot, spiral through the spine.

The science note at the end cited Dr. Martin Gibala’s research at McMaster showing that short interval sessions match or exceed hours of moderate cardio for VO2 max and metabolic function. Then it linked his book.

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Chris came back and asked for more.

This time: TRX, sandbell, and jump rope together. Coach Keir AI called it the Foghorn Full-Body Athlete and built a 40-minute, 4-round session.

Warm-up: jump rope 2 minutes easy rhythm, TRX hip hinge x10, TRX chest stretch 30 seconds each side, sandbell halo x8 each direction.

The circuit: jump rope double time for 60 seconds, TRX atomic push-up for 8 reps (full push-up, then drive both knees to chest simultaneously at the top — hips level, no piking), sandbell rotational slam for 10 reps (load the hip on one side, rotate through the torso, slam at a diagonal, alternate sides — pure rotational power), TRX suspended lunge for 8 each leg (rear foot in the cradle, front foot planted, sink straight down — these will humble you fast at any fitness level), sandbell clean and press for 8 reps, TRX row for 12 reps (body at 45 degrees or lower, pull elbows past ribs, squeeze scapulae at the top, slow the eccentric on the way down — that’s where the gains live), jump rope single leg alternating for 30 seconds each leg (balance and coordination challenge as much as cardio — if you lose it, reset and go again, no ego), sandbell lateral lunge and reach for 6 each side (step wide, sit into that hip, reach the sandbell toward the outside of the foot at the bottom — loaded hip mobility pattern, perfect for longevity goals).

Finisher after round 4: sandbell farmer carry 2×40 steps, jump rope 90 seconds your choice of tempo, TRX plank hold 60 seconds.

Recovery note from Coach Keir AI: after a session like this, the lymphatic system needs to move that metabolic waste out. Don’t just collapse on the couch — take a 10-minute walk, get some elevation in the legs, and hydrate. That’s where the adaptation happens.

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Brought a Smile to My Face.

This is the app doing exactly what it was built to do. Bob and Chris train with me regularly in San Francisco. This week, while I’m in a car somewhere in the Mountain West, they are getting complete Foghorn-style sessions with full coaching cues, exercise science citations, and recovery protocols — built specifically for the equipment they have in front of them, in real time.

The free tier gives you ten exchanges with Coach Keir AI. Start there. Ask it what to do with the equipment you have. See what comes back. There are also a handful of written and video-on-demand workouts already loaded up in the app; you can run those if you’re feeling lucky. But remember, this is not just something for heavy-sweating gym rats (and no, I’m not suggesting that Bob and Chris are heavy-sweating gym rats). If you want to learn how to breathe better, eat better, sleep better, manage stress better, etc.—The app and I are here for you. Even if one of us is gripping a steering wheel non-stop for the next week.

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One more thing: want to talk to the real Coach Keir?

This is new. I’ve added an easy way to book a free 30-minute introductory call with me to learn more about the Slowfit Method® and/or my AI Coach app, to discuss your training goals, or to explore what a private coaching relationship might look like. No pressure, no pitch — just a conversation.

BOOK HERE

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One more pitch for the app! The Slowfit Method® app puts Coach Keir AI in your pocket — trained on all ten pillars including Movement and Strength. One hundred people have already downloaded this app, and I’ve got nine 5-star reviews on the App Store. Check it out! Slowfit Paid is $29.99 a month — a dollar a day — and gives you unlimited coaching chat conversations, full Vault access, and a growing library of on-demand workout videos.

GET THE APP

Stick around.

Best,

Keir

Keir J. Beadling is a human performance coach, founder of Foghorn Fitness, and creator of the Slowfit Method®. He coaches athletes and everyday humans in San Francisco and worldwide. More information is available at foghornfitness.com.

YOU TAKE 20,000 BREATHS A DAY. HERE’S WHY MOST OF THEM ARE WORKING AGAINST YOU.

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At the end of the last post in this series — the Mindset pillar — I teased what was coming next.

Breathing. Specifically, why the way you breathe right now — most likely through your mouth, shallowly, chaotically — is undermining your performance, your sleep, and your stress response.

That was not hyperbole.

You take roughly 20,000 breaths a day. It is the only autonomic function you can also consciously control — the hinge point between your voluntary and involuntary nervous systems. And for most people reading this, the vast majority of those 20,000 breaths are making things worse. Not by a little. By a lot.

Let’s talk about why, and what to do about it.

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James Nestor changed how I think about this

I referenced James Nestor in the walking post — noting that what he did for breathing, Conley and McDowell did for walking. Let me back up and actually give him his due here, because his book Breath: The New Science of a Lost Art is the text that cracked this topic open for me and for a lot of people.

Nestor spent years reporting on breathing, including blocking one nostril and spending ten days breathing exclusively through his mouth while scientists monitored everything that happened. Blood pressure went up. Snoring started. Sleep deteriorated. Cognitive function declined. Athletic performance dropped.

Then he switched to nasal-only breathing for ten days. Everything reversed.

His core finding: humans a long time ago breathed correctly. We have systematically unlearned how. The fossil record shows it — ancient skulls have wide jaws, spacious airways, straight teeth. Modern skulls, starting roughly with the industrial revolution and accelerating sharply with the rise of processed food and sedentary indoor life, show narrowed jaws, crowded teeth, reduced airway diameter, and the structural consequences of a species that has stopped chewing hard food and started breathing through its mouth.

This is not a minor lifestyle quibble. Nestor’s argument is that dysfunctional breathing is at the root of conditions ranging from anxiety and poor sleep to cardiovascular disease and immune dysfunction. And the fix — at its most fundamental — is embarrassingly simple: close your mouth.

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Patrick McKeown on The Ready State

If Nestor is the journalist who broke the story, Patrick McKeown is the scientist who built the clinical framework around it.

McKeown is the founder of the Buteyko Clinic, author of The Oxygen Advantage, and one of the world’s most rigorous researchers on functional breathing. He recently appeared on The Ready State podcast with Kelly and Juliet Starrett — and given that Kelly Starrett is the person I credit for transforming how I think about mobility, movement, and physical preparation, this was a conversation I paid close attention to.

The key ideas from that episode:

Most people are chronically over-breathing. This sounds counterintuitive — we tend to think more breath equals more oxygen. But breathing too much actually depletes CO2, which is not just a waste gas. CO2 is the signal that tells your red blood cells to release oxygen to your tissues. When you over-breathe and drive down CO2, your body actually delivers less oxygen to where it needs to go, despite you breathing more. Paradox. A real one.

The BOLT score is your breathing baseline. BOLT stands for Body Oxygen Level Test. Take a normal breath in through your nose, exhale normally, then pinch your nose and time how long it takes before you feel the first urge to breathe. Not the maximum you can hold — just the first urge. A score under 20 seconds indicates dysfunctional breathing. Elite endurance athletes typically score 40 seconds or more. Most sedentary adults score 10 to 15 seconds. This one number tells you a lot about your CO2 tolerance, your anxiety baseline, and your recovery capacity.

McKeown also covers why women experience breathing and sleep differently than men — particularly around menopause — and why many sleep disorders in women may be going undiagnosed because sleep studies were historically designed around male breathing patterns. Example number 5,345 of how women are not just small men.

Mouth breathing in kids is a hidden developmental crisis. Mouth breathing in children has been proven to cause poor academic performance, craniofacial deformities, dental problems, and behavioral issues. If you have kids, this episode is worth paying very close attention to.

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How to Measure Your CO2 Tolerance: The CO2 Exhale Test

Jesse Coomer’s The Language of Breath offers a complementary test to the BOLT score — one I’ve found particularly useful because it measures a different dimension of CO2 tolerance. This protocol was originally developed by elite fitness trainer Brian Mackenzie. It’s the one with which Foghorn athletes are the most familiar.

Where the BOLT score measures how long you can go before the urge to breathe strikes, the CO2 Exhale Test measures how long and slowly you can exhale — which reflects your nervous system’s relationship with CO2 and your actual breathing control.

Wanna give it a shot right now? Before taking the test, breathe normally. Don’t practice or mimic the test first; just breathe naturally. You will need a stopwatch.

Step 1: Take a deep breath through your nose and relax it out to neutral lungs.

Step 2: Wait until you feel the urge to breathe, then take another deep breath and relax it out to neutral lungs.

Step 3: Wait until you feel the urge to breathe again, then take a deep and full breath through your nose.

Step 4: Begin the timer as you exhale through your nose for as long and as slowly as you can.

Stop the stopwatch when any of the following occur: you completely run out of air; you swallow; or there is any interruption in the airflow as you exhale.

Your time is your score.

Scores and their meaning:

0 to 20 seconds: Very poor CO2 tolerance. Retest the following day to confirm — many people score low when under significant stress or illness. Before working on CO2 tolerance techniques, get this score to at least 21. Cardiovascular exercise is one of the best ways to improve it naturally. Do not jump into advanced CO2 tolerance training at this stage; it will add stress rather than improve tolerance.

21 to 40 seconds: Average modern human. You can begin CO2 tolerance training. You have significant room for improvement. This is where most of my athletes start out.

41 to 60 seconds: Advanced. A healthy range. You generally have a relaxed and smooth breathing pattern and can slow your breathing down relatively easily after exertion.

61 to 80 seconds: Elite. Your natural breathing pattern is slow and smooth, you rarely breathe more than you need to, and you experience increased resilience against stressors.

80 seconds and above: Master. You have become very comfortable with CO2 and are highly resilient against stress. I have athletes who’ve been training with me for a few years—which means they’ve been training their breath with me for that long—who are bumping along towards two and a half minutes. Yep.

Take both tests — the BOLT and the CO2 Exhale Test — and you have a meaningful baseline picture of your breathing health. Most people are surprised by how low they score. That’s not a reason for discouragement. It’s a reason to train.

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The Language of Breath: where conscious meets unconscious

I recently read Coomer’s The Language of Breath — endorsed by McKeown himself , by the way — and it has a framing I really like.

Coomer’s core argument is that breathing is the one function where the conscious and unconscious self meet. Your heart beats without you. Your digestion runs without you. Your immune system operates without you. But your breath does all of this automatically — and also responds instantly to your conscious direction. It’s the bridge.

He cites the research: 95 percent of brain activity is unconscious. Your senses are reporting approximately eleven million pieces of information at any given moment. You consciously process about forty. The rest — your heart rate, your posture, your emotional state, your stress response — is being handled by your unconscious self, constantly, relentlessly, using everything it knows about your history and your environment.

Your breath is continuously informing that system. When you mouth-breathe, shallowly, rapidly, your unconscious self interprets this as a threat signal. It doesn’t know you’re just sitting at a desk answering email. It knows your breathing looks like the pattern of someone in danger. And it responds accordingly.

Coomer’s framing: “Most of our troubles in the modern age come from a lack of awareness of these foundational relationships.” We have become, in his words, mind-body machine operators rather than whole beings. Breathing, done correctly, is how you start to close that gap.

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Jaws: the structural problem underneath everything

No conversation about dysfunctional breathing is complete without talking about the jaw.

Sandra Kahn and Paul Ehrlich open the relevant chapter of Jaws: The Story of a Hidden Epidemic with a line that I love: “Our jaws are built for a Stone Age diet, but we’re living in a Big Mac environment.”

Sheee-it. Nailed it.

That single sentence explains a remarkable amount. Our jaws are built for a Stone Age diet — tough meats, fibrous tubers, nuts, fruits that required real chewing effort, hours of it daily. What we get instead is soft bread, yogurt, applesauce, processed food bolted down in minutes. Kahn and Ehrlich identify three core areas of cultural shift that have driven the modern jaw crisis: what we eat and how we eat it, slack jaw and prevailing oral posture, and indoor living and how we breathe. All three are interconnected. All three are getting worse.

The structural consequences are measurable and serious. The human jaw has been shrinking for roughly 300 years. The result is narrow palates, crowded teeth, reduced airway diameter, and a structural predisposition to mouth breathing, snoring, and sleep-disordered breathing. Children of parents who cut food into tiny pieces — out of fear of choking — miss out on the learning experience of how the tongue and muscles coordinate to maximize extraction of nutrients from a meal, and don’t get the muscle exercise needed for healthy jaw development.

Orthodontia fixes the cosmetic symptoms. It doesn’t fix the airway.

If you struggle to breathe through your nose, there may be a structural reason. Addressing it — through myofunctional therapy, palate expansion, or airway-focused dental work — may matter more than any breathing protocol. And chewing more — harder foods, longer duration, starting in childhood — is the lowest-cost, highest-impact intervention available.

In the meantime, work on proper oral posture—mouth closed, teeth lightly touching, tongue pressed up against the soft palate. Simple, right? Kids, too.

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What the research is showing

The science on breathwork has matured significantly in recent years.

A meta-analysis of randomized controlled trials showed that breathwork interventions significantly reduced self-reported stress, anxiety, and depressive symptoms. Slow-paced breathing was particularly effective in promoting parasympathetic activity and increasing heart rate variability.

Even single sessions of as little as two minutes of slow breathing have been shown to increase HRV, suggesting breathwork is accessible, cost-effective, and immediately impactful.

A 2024 randomized controlled trial published in JAMA Open Network found that physicians who regularly practiced structured breathwork over two months experienced significant decreases in insomnia, stress, and anxiety.

For athletes, the data on nasal breathing during training is accumulating. McKeown’s Oxygen Advantage framework — training with nasal-only breathing during moderate-intensity work — has been shown to improve CO2 tolerance, increase VO2 efficiency, and reduce the ventilatory threshold. Kipchoge ran his sub-two-hour marathon with his mouth closed for most of it! Worth noting.

If you are using Whoop and your HRV is suppressed, your breathing habits during the day and during sleep may be a primary driver.

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Practical takeaways

The good news: the interventions are free, require no equipment, and can begin immediately.

Take both tests. Do the BOLT score and the CO2 Exhale Test today. Write both numbers down. These are your baselines. Return to them in four weeks of nasal breathing practice and see what changes.

Tape your mouth at night. McKeown and Nestor both do it. Micropore medical tape across the lips encourages nasal breathing during sleep, reduces snoring, and improves sleep quality for many people within a few nights. Works for me.

Train nasal. During easy and moderate-intensity training — your Zone 2 work, your warm-up, your cool-down — breathe exclusively through your nose. If you can’t maintain nasal breathing at a given pace, slow down. Your pace will catch up to your breathing capacity over weeks of training.

Use the downregulation protocol before bed. Nasal breathing only, belly-led inhales, exhale twice as long as the inhale, 4-count in and 8-count out, three to five minutes minimum, thirty minutes before bed. This is your direct dial into the parasympathetic nervous system. Use it every night.

Practice box breathing for stress. Four counts in through the nose, four counts hold, four counts out through the nose, four counts hold. Four rounds. This is what military units use for acute stress regulation.

Chew. Hard foods, more often. Sugar-free xylitol gum. Tougher proteins. Raw vegetables. Your jaw is a use-it-or-lose-it structure — and relatively little chewing early in life can alter the development of your entire face, jaws, and airways.

Learn the Wim Hof Method for upregulation. And here’s one more big one, as every Foghorn athlete knows: Wim Hof Method upregulation breathing. Every training session I run – bootcamp, 1:1, Zoom – begins with a round of Wim Hof Method breathing. This is the other side of the breathwork coin. Where the downregulation protocol dials you down, WHM dials you up. It is a deliberate, controlled form of hyperventilation that primes your nervous system, floods your body with adrenaline, alkalizes your blood, and generates a state of heightened focus and physical readiness before you start moving. I’ve been using it as a warmup tool for years, and the science has been catching up fast. A 2024 systematic review in PLOS ONE found promising evidence for WHM’s effects on inflammatory response and exercise performance. A randomized controlled trial published in 2024 showed WHM practice reduced depressive symptoms and stress – with high-arousal WHM-style breathing specifically outperforming calming protocols for some individuals, challenging the assumption that breathwork should always be downregulatory. A 2023 study in Scientific Reports found that 15 days of WHM practice improved blood pressure, HRV, and subjective vitality.

The protocol: sit or lie down comfortably. Take 20 to 30 deep, powerful breaths – inhale fully through the nose or mouth, then let go without forcing the exhale. Keep a steady, rhythmic pace. After the final exhale, hold your breath with empty lungs for as long as comfortable – most people start at 60 seconds and build to two or three minutes over time. Then take one deep recovery breath, hold it for 10 to 15 seconds, and release. That’s one round. Do three to four rounds. You will feel tingling, lightheadedness, and a warmth spreading through your body – all normal, all physiological. Do not do this in water, while driving, or anywhere a loss of consciousness would be dangerous. When you finish, you are primed. Now go train. For the full method, Wim Hof’s book is the place to start: The Wim Hof Method.

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Next up in this series: Nutrition. Specifically, why the most important dietary intervention most people could make costs nothing, requires no supplements, and is not a diet at all.

All ten pillars of the Slowfit Method® live here on Substack and at foghornfitness.com. Paid subscribers get deeper dives, workout programming, and the full resource library.

The Slowfit Method® app puts Coach Keir AI in your pocket — trained on all ten pillars including this one. Ask it anything about your breathing, your CO2 tolerance, your sleep, or your stress. One hundred people have already downloaded this app, and I’ve got nine 5-star views on the App Store. Check it out!

Get the app

And if you’re interested in a 1:1 private coaching relationship, you can book sessions at foghornfitness.com . You can even book a free intro discussion with me to learn more about how the Slowfit Method® could amp up your performance, health and happiness.

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Stick around.

Best,

Keir

Keir J. Beadling is a human performance coach, founder of Foghorn Fitness, and creator of the Slowfit Method®. He coaches athletes and everyday humans in San Francisco and worldwide. More information is available at foghornfitness.com.

THE PEOPLE WHO KNOW ME BEST SHOWED UP FIRST.

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When I launched the Slowfit Method® app, I wasn’t sure who would show up first in the reviews. What I didn’t expect — and what means more to me than I’ll probably admit — is that the first people to leave public reviews in the App Store are people who actually know me. A couple former clients. A current client. Good friends.

These aren’t strangers being generous to a product they stumbled across. These are people who have trained with me, withstood my harangues about mobility and sleep, and have a very high bar for what good coaching looks like. No BS. When they put their name on something publicly, they mean it.

We’re nearly 100 downloads in. Every review so far is five stars. Here’s what they said.

Foghorn Fitness is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid Substack subscriber.

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“Great app, great coach” — Lhitchcock

“Just used the Slowfit Coach to design a custom workout with my specific fitness issues and goals. I also work with Coach Keir in person and this app is a great extension of his expertise. Perfect complement…”

A current training client. Someone who knows exactly what my in-person coaching looks like — and is telling you this holds up against it.

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“Yes!!!!” — Govivo

“Love this app!”

Short, enthusiastic, unambiguous. From a good friend who has watched this project develop for a long time and knows what went into it.

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“Impactful App” — dgathlete

“Coach Keir has nailed it w this app. Super engaging w insights honed over decades training athletes (and non athletes!) alike. Highly recommend!”

A buddy and former athlete of mine. Someone who trained with me and has been in the trenches of the Slowfit Method® framework firsthand. “Insights honed over decades” — that’s someone who has experienced what that actually means.

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“Get this app!” — Past Foghorn athlete

Another former athlete. Four words. No ambiguity.

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Four written reviews. Nine five-star ratings. All from people with direct experience of what this coaching framework looks and feels like in practice. That’s the kind of signal that matters.

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Then something shifted.

This past week, a number of new downloads came in from people I don’t recognize. Not clients. Not friends. Not bootcamp group exercise regulars. Strangers. People I have never met, who found the app on their own and decided to download it.

I’ll be honest — I have no idea how they’re finding it. My marketing budget is zero dollars. There are no ads. No paid placements. No influencer partnerships. Just this Substack, word of mouth, and apparently the universe doing its thing.

People are finding the app.

That is an extremely rewarding thing to sit with. It means the work is traveling on its own. It means someone told someone, or a Substack post landed in front of the right eyes, or someone searched for something and the app showed up. Whatever the path, they found it. They downloaded it. And presumably they’re using it.

That’s the whole experiment. And it’s working.

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What people are actually doing with it

Folks are using the app exactly as I intended. As a tool, not as an infinite scroll machine.

My niece Mackenzie and her new husband Jimmy were on a family vacation — 2,500 miles from their human coach uncle — when she opened the app and typed one sentence to Coach Keir AI: “I want a 20 min body weight strength workout to do on vacation today.” What came back was a complete structured session with warm-up, a three-round circuit, coaching cues, and a cool-down. They did it outside in the grass by a lake together. She texted me a sweaty selfie afterward. That’s the whole point of everything I’m trying to build.

Chili is a Tuesday morning bootcamp regular at the Presidio YMCA. He showed up to class, trained hard, and then — that evening — used the app to ask Coach Keir AI how to optimize his sleep after a tough workout. He got a specific, science-backed protocol tailored to the physiological demands of what his body had just been through. Not a generic sleep tip. A coaching answer to a coaching question.

Then there’s the trio I wrote about in the Ten-Question Rule post a few weeks ago. Kari asked for a 10-minute mobility flow she could do anywhere and got Kelly Starrett’s Ready State protocol with the science behind it. Alicia asked about the Nutrition pillar of the Slowfit Method® and one action she could take today, got three words — “eat real food” — and a full framework, and went to read ingredient labels. Andy asked what the most important thing he could do tonight to improve his sleep was, got a complete downregulation breathing protocol, and went to bed. None of them needed a follow-up. None of them stayed on the app longer than they needed to.

Ten free exchanges with Coach Keir AI. Used wisely. Like wishes from a genie, not chips at a casino.

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The real Coach Keir is going on vacation. The AI one isn’t.

Here’s something I’ve been thinking about as I pack for a month away (and prep for a cross-country solo drive with our new puppy).

I built The Slowfit Method® app specifically for moments like this one. Clients, group exercise athletes, and others are already telling me they’re planning to use it while I’m gone — to help them sleep, eat well, train smart, and recover properly, all while their human coach is physically unavailable. That is exactly the use case I built this for.

The real Coach Keir needs to unplug. He needs to recharge. A month away on a beach, away from the bootcamp, away from the Zoom calls. Quality family time. That’s not a bug in the coaching model — it’s a feature of being a sustainable human being.

The AI Coach Keir doesn’t need a vacation. He’s available at 11pm when you can’t sleep. At 6am when you’re deciding whether to train. On a Tuesday afternoon when you’re trying to figure out what to eat before a long run. When you’re freaked after a tough work conversation and need a quick downregulation breathing protocol. He’s there. He doesn’t get tired. He doesn’t need to recharge. And he’s drawing on the same decade of methodology that I bring to every in-person session and every Zoom call.

I built the app for exactly this purpose. I’m about to prove it works.

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What this is and isn’t

The Slowfit Method® app is not a generic AI fitness tool that aggregates whatever is trending on the internet this week. It is not a chatbot trained on Wikipedia and Reddit threads about protein shakes. It is a decade of training and coaching methodology, pillar by pillar, encoded into an AI system that responds the way I would respond — because it was built on the framework I use with real clients in real sessions.

That’s what dgathlete means by “insights honed over decades training athletes (and non athletes!) alike.” That’s what Lhitchcock means by “a great extension of his expertise.” The app doesn’t replace the human coach. It extends him into places and hours the human coach can’t be. 2,500 miles away. 11pm on a Tuesday. A month away on vacation.

The Vault inside the app contains 300+ personally curated books, podcasts, gear, and supplement recommendations organized by Slowfit pillar. Coach Keir AI draws on all ten pillars — Purpose, Mindset, Breathing, Sleep, Nutrition, Movement, Recovery, Hydration, Community, and Strength — in every conversation.

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The free tier is real. So is the upgrade.

The free tier gives you ten exchanges with Coach Keir AI. Use them wisely and you will get genuine value. Treat them like chips at a slot machine and you’ll burn through them on questions you could have Googled.

Slowfit Pro is $29.99 a month — a dollar a day — and gives you unlimited coaching conversations, full Vault access, and a growing library of on-demand workout videos.

Plus, I’m gonna keep this t-shirt thing going, since I love seeing Foghorn schwag out in the wild. So I’m offering a Foghorn Fitness t-shirt to the next two people who upgrade to a paid subscription. I’ll mail it to you personally. To upgrade, open the app, go to Settings, and tap Change Plan. Thirty seconds.

Download the Slowfit Method® app here:

GET THE APP

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I’ll be writing from the road with Ellie. More use cases, more Slowfit pillar posts, and more from the other side of the country where I end up.

Stick around.

Best,

Keir

Foghorn Fitness

The Month Cartilage Science Changed Everything — And What It Means For Your Knees Right Now

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A few weeks ago I wrote about my own knee osteoarthritis diagnosis — the swollen left knee that wouldn’t quit, the 30cc of fluid my orthopedic surgeon’s staff drained in his office, the Baker’s cyst, the MRI findings, the cortisone shot, the pending hyaluronic acid injection series. I promised updates as things developed.

Here’s the update: I just completed a multi-day karate special training. Strenuous, demanding, the kind of training that tests your entire body and your mind in equal measure. My knee is still not perfect. The inflammation is ongoing. And I did it anyway — not because I was reckless, but because the emerging science told me I should. And because I’m in the business of continuing to do the things that I love, that give my life meaning.

More on that in a minute.

First, I want to tell you about what has happened in cartilage science in the last several weeks. Because I think we are genuinely watching a paradigm shift in real time. And if you have osteoarthritis, or know someone who does, you need to understand what’s coming.

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Three Pieces of Research. One Converging Message.

Let me lay out what’s happened in quick succession, because the timing is remarkable.

**Piece One: The Biological Framework (Howard Luks, MD)**

Howard Luks — sports medicine orthopedic surgeon, one of the most evidence-based voices in joint health — has been arguing for years that the conventional model of osteoarthritis is simply wrong. The “wear and tear” framing that leads patients to stop moving, stop loading, stop doing the things they love is not supported by the biology. As Luks writes, cartilage is a living, biologically active tissue that gets its nutrients from synovial fluid — and the only way synovial fluid circulates through cartilage is through compression and release. Load the joint, unload it, load it again. Movement nourishes cartilage. Inactivity starves it.

The primary driver of OA progression, Luks argues, is not mechanical grinding but chronic low-grade inflammation — specifically the cytokines IL-6 and TNF-alpha — that poisons the cellular environment where chondrocytes (cartilage-making cells) are trying to do their jobs. Your knee is downstream of your systemic biology. Everything that reduces your inflammatory load protects your joints.

This framing matters because it completely reorients what you should be doing about OA. Not resting. Not restricting. Training smartly, sleeping well, eating clean, managing stress — these are joint protection strategies, not just general wellness platitudes.

**Piece Two: The Exercise Intensity Study (Song & Meng, Medicine, May 2026)**

A randomized controlled trial published in Medicine in May 2026 put 120 patients with moderate knee OA (Kellgren-Lawrence Grade 2-3) into four groups: low-intensity aerobic exercise (50-60% heart rate reserve), moderate-intensity (60-70% HRR), high-intensity (70-80% HRR), or a control group. Three sessions per week, 30 minutes of treadmill walking or stationary cycling, continuously heart rate monitored, for 12 weeks.

The results were remarkable across every measure they tracked.

The high-intensity group saw a 28.5% drop in serum CTX-II — a direct biomarker of cartilage breakdown — over 12 weeks. The control group got slightly worse. On MRI, the high-intensity group increased medial cartilage thickness by 4.8% and volume by 4.2%. Pain dropped 52.5%. WOMAC scores — a comprehensive measure of OA pain, stiffness, and function — improved 45.3%. The 6-minute walk test improved by 71 meters, nearly triple the established threshold for clinical meaningfulness. 80% of high-intensity participants achieved clinically meaningful pain relief.

No serious adverse events. Zero dropouts due to exercise-related problems. These were people with moderate osteoarthritis exercising vigorously for 12 weeks.

Loading the joint did not thin the cartilage. It thickened it.

The dose-response data showed a threshold effect between 60-70% HRR where the benefit curve gets dramatically steeper. For most people, the sweet spot appears to be roughly 65-75% of heart rate reserve — vigorous but sustainable. The authors’ own conclusion: current exercise recommendations for knee OA patients are overly conservative, and many patients could safely tolerate and benefit from significantly more intense exercise than has traditionally been prescribed.

**Piece Three: The Stanford Breakthrough (Agarwal, Su, Ancel et al., Science, June 12, 2026)**

And then, just weeks after the Song & Meng paper, Stanford Medicine published what may be the most significant development in OA research in decades.

The study, published in Science, identified a single aging-related enzyme — 15-hydroxyprostaglandin dehydrogenase, which the researchers term a “gerozyme” because it accumulates with age and drives tissue degeneration — as a master regulator of cartilage aging. Block this enzyme, and something remarkable happens: existing chondrocytes undergo transcriptional reprogramming to a more youthful state. They don’t need to be replaced. They don’t need stem cells. They just need the aging brake released.

In aged mice, small-molecule inhibitors of 15-PGDH promoted cartilage thickening and regeneration of functional hyaline cartilage — the smooth, load-bearing kind, not scar tissue. The treatment reversed natural age-related cartilage thinning, improved joint function, and when administered after simulated ACL injuries, strongly mitigated post-traumatic OA progression and associated pain.

Most compellingly: human OA cartilage explants from total knee replacement surgeries — worst-case specimens, cartilage so degenerated it required surgical removal — showed decreased degradation markers and evidence of new articular cartilage formation when exposed to the 15-PGDH inhibitor in the lab.

And crucially, an oral version of the 15-PGDH inhibitor has already completed Phase 1 safety trials for age-related muscle atrophy. The safety profile is established. The path to a cartilage-specific clinical trial is shorter than starting from scratch.

Helen Blau, the Stanford researcher leading this work, put it plainly: “Imagine regrowing existing cartilage and avoiding joint replacement.”

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Why This Convergence Matters

Three independent lines of research — a clinical framework, a randomized controlled trial, and a molecular biology breakthrough — landing in the same window, pointing in the same direction.

The old model: OA is irreversible mechanical wear. Cartilage grinds down. Rest what’s left. Manage pain until you need a new joint.

The emerging model: OA is primarily a biological failure — chronic inflammation, aging-related molecular brakes, a cellular environment that has become hostile to the very cells responsible for maintaining cartilage. And biological failures can be addressed biologically. Through exercise. Through systemic inflammation management. And potentially, soon, through targeted molecular intervention that allows your own chondrocytes to become youthful again.

This is not incremental progress. This is a paradigm shift.

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The Caveats

I’m not going to oversell this, because we all deserve the full picture.

The Stanford study showed human cartilage regeneration in vitro — in a lab dish, not in a living human patient. Mouse-to-human translation in cartilage research has historically been difficult. The jump from promising preclinical results to clinical reality is where most breakthroughs stumble. Realistically, if the 15-PGDH inhibitor clears Phase 2 and 3 trials for cartilage regeneration, you’re probably looking at 3-5 years minimum before it’s available to patients. That’s fast by drug development standards. It is not imminent.

The Song & Meng study lasted 12 weeks with 120 participants. The authors themselves note that the short-term MRI cartilage changes may partly reflect alterations in cartilage hydration rather than true structural remodeling, and that longer-term studies are needed to confirm genuine tissue regeneration.

And the Luks framework, while compelling and well-supported, is still fighting against decades of conventional medical conservatism. Most orthopedic surgeons are still telling their OA patients to take it easy (including my own, sigh).

What I’m saying is: the direction of the evidence is clear and genuinely exciting. The clinical applications require patience.

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What I’m Doing Right Now — And What You Should Consider

I want to share my own protocol, because I think it’s the most practical thing I can do.

**Exercise intensity as medicine.** Based on Song & Meng, my therapeutic target on the bike is 65-75% of heart rate reserve. With my resting HR of 45 and max HR of 175, that’s roughly 128-143 bpm — Whoop Zone 3, comfortably hard, sustainably challenging. Ideally three sessions per week, 30 minutes of work. This is the study protocol, and I’m treating it that way.

**VMO strengthening.** My MRI showed lateral patellar subluxation — my kneecap tracks too far to the outside, which is a primary driver of my patellofemoral OA and inflammation. Terminal knee extensions, backward sled drags (Kelly Starrett’s recommendation), and heavy standing bike climbs are my primary VMO tools. The patella tracks where the VMO tells it to. Strengthen the VMO, improve the tracking, reduce the grinding.

**Systemic inflammation management.** The Slowfit Method® pillars are not just training advice — they are, in the context of OA, direct joint protection strategies. Sleep quality, clean nutrition, stress management, lean body composition: all of these reduce the inflammatory cytokine load that drives OA progression. Every pillar is working in service of every other pillar.

**Voltaren topically, not Aleve systemically.** Topical diclofenac delivers NSAID-level anti-inflammatory action directly to the joint with roughly 6% of the systemic absorption of oral NSAIDs. Lower risk, more targeted. My default post-activity tool. I don’t love the idea of leaning on NSAIDs for anything, but as Kelly Starrett says, to stay ahead of the snowstorm, you’ve gotta sweep the front steps every hour. One of those sweeps, for me, is a little Voltaren.

**Normatec for lymphatic clearance.** Pneumatic compression after training sessions to move fluid and support recovery. Not a treatment — a recovery tool.

**The HA injection series coming next month.** Hyaluronic acid viscosupplementation to restore the joint’s natural lubricating environment before I start loading it with Starrett-level work.

**And the karate.** I just completed a demanding multi-day special training that would have been unthinkable six months ago when the knee was at its worst. Not pain-free, not without managing it carefully before, during, and after. But done. Because the evidence told me that movement is the medicine, fear of movement is the enemy, and an active 57-year-old with moderate patellofemoral OA who keeps training is doing more for his cartilage than one who sits on the couch waiting to feel better.

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A Note on Howard Luks

I’ve reached out to Dr. Luks directly for his perspective on the Stanford study. His read on how the 15-PGDH research intersects with the exercise intensity data — and what it means clinically for active patients managing OA right now — is worth having. I’ll update this post or publish a follow-up when I hear back.

If you’re not already reading Luks’ Substack, you should be. He is one of the authentic, most honest voices in orthopedic medicine writing for a general audience today.

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Why We Do This

The oft-cited Kelly Starrett — physical therapist, coach, mentor, and one of the clearest thinkers in the movement and performance space — talks about training in terms of “spending credits.” The idea is simple: we put in the work so that we can spend the credits on the activities we love. The training is not the point. The training is what makes the point possible.

For me, that means triathlon. It means karate. It means being able to toe the start line at the Escape from Alcatraz, to show up for special trainings, to get smashed around on my surfboard, to keep doing the things that make me feel most alive at 57. The knee work — the Zone 3 cycling sessions, the VMO strengthening, the backward sled drags, the HA injections, the Voltaren, the Normatec, the sleep and nutrition discipline — none of it is the destination. It’s the price of admission for the life I want to keep living.

That’s what the Slowfit Method® is ultimately about. Not optimization for its own sake. Training as a means to a life fully lived. And the emerging science around OA — exercise as cartilage medicine, chondrocytes capable of becoming youthful again — tells us that life can be longer, more active, and more capable than we previously had any right to expect.

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The Slowfit Method® Take

None of this surprises me from a Slowfit Method® perspective. What it does is give us a richer, more precise scientific language for what we’ve been building here.

The Slowfit Method is, at its core, a biological framework for human performance. We train because training creates adaptive signals. We treat sleep, nutrition, stress management, and recovery as pillars — not accessories — because your body is a system and every pillar affects every other one. We monitor training load and recovery state because the dose matters.

The emerging OA science adds a beautifully specific prescription: the active person navigating knee osteoarthritis should not back off. They should lean in — smartly, progressively, with heart rate guidance, with the other pillars in order. The goal is to provide the biological stimulus your cartilage needs, maintain the synovial fluid circulation that nourishes chondrocytes, and keep the systemic inflammatory environment as calm as possible while you wait — with genuine hope now — for the molecular therapies that may soon be able to do what no drug has ever done before.

Repair the joint itself.

More updates to come. In the meantime, keep moving. Your cartilage is counting on it.

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Take the Slowfit Method® With You

If you want to put these principles into daily practice, the Slowfit Method® app is now available on iOS. Training guidance, recovery protocols, and the full Slowfit Method® framework — built into a tool you can use every day. I’ve been building this for a while and I’m genuinely proud of what it’s become.

Get the app

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*Nothing in this newsletter constitutes medical advice. If you’re dealing with joint pain, please see a qualified sports medicine physician or orthopedic surgeon. The information here is intended to complement — not replace — professional medical guidance.

Questions, reactions, pushback? Hit reply. I read everything.

Keir

Foghorn Fitness

foghornfitness.com | foghornfitness.substack.com

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Foghorn Fitness is home to The Slowfit Method® — a science-backed, whole-person approach to human performance. If someone forwarded this to you and you’d like to subscribe, we’d love to have you.

THE TEN-QUESTION RULE

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The free tier of the Slowfit Method® app gives you ten exchanges with Coach Keir AI.

Ten.

When I tell people that, the first reaction is usually some version of: that’s not very many. And I get it. We live in an era of unlimited everything. Unlimited streaming, unlimited scroll, unlimited storage. Ten feels like a parking meter in a world where everything else is free parking forever.

But here’s what I’ve noticed in the coaching admin dashboard, watching real users move through the app: ten is plenty. More than plenty. For a lot of people, ten is exactly right.

Because the users who are getting the most out of the free tier aren’t treating their questions like chips at a casino. They’re treating them like wishes from a genie.

You’ve heard the rule. Three wishes. You don’t waste them on a baloney sandwich. You think carefully. You ask the question that actually matters. You are intentional (and you are now likely getting a sense for why I call this “Slowfit,” right? As in slow streets, slow food, slow parenting, etc.)

That’s what I’m watching people do.

Foghorn Fitness is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

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KARI

Her question: “Give me a 10-minute mobility flow I can do anywhere.”

Coach Keir AI pointed her to Kelly Starrett’s morning mobility routine from The Ready State — a progression I’ve personally used before every single training session since 2021. Hip flexors, thoracic spine, shoulders, ankles. The full sequence. Plus a pointer to Built to Move for anyone who wants to understand the why behind the what.

Kari got a complete protocol rooted in the best mobility science I know. Then she closed the app and went to go do it.

That’s the whole point.

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ALICIA

Her question: “Tell me about the Nutrition pillar of the Slowfit Method® and give me one action I can take today.”

Coach Keir AI gave her the real answer: four words. Eat real food. Then unpacked it — Herman Pontzer’s research on why you lose weight in the kitchen, not the gym. Dr. Robert Lustig’s case against ultra-processed food as the root of modern chronic disease. The CGM data I ran for nearly three years and what it actually showed me.

Her one action for the day: read every ingredient label on everything she ate. If it had more than five ingredients, or ingredients she couldn’t pronounce, put it back.

One question. One framework. One action. Done.

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ANDY

His question: “What is the most important thing I can do tonight to improve my sleep?”

Coach Keir AI gave him a downregulation breathing protocol — nasal only, belly-led inhales, exhale twice as long as the inhale, 4-count in and 8-count out, body scan from head to toe, 3 to 5 minutes minimum, starting 30 minutes before bed. It’s not complicated. It’s a direct line into the parasympathetic nervous system. The science is about as solid as it gets.

Andy’s habit log already shows he’s been tracking sleep. He came in with a real question. He got a real answer. He didn’t need a follow-up. He needed to go to bed.

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Here’s what strikes me about all three of these interactions—

None of them burned through their ten questions on things they could have Googled. None of them treated the AI coach like a toy to pass time. They showed up with a real question — something that had been sitting in the back of their mind or triggered by one of the app’s home screen prompts about the big behavioral levers — and they left with something they could use. Today. Tonight. Tomorrow morning.

Then they closed the app and went back to their lives.

This is the opposite of how almost every other app on your phone is designed to work. Social media doesn’t want you to get what you need and leave. It wants you to stay. It wants you confused, reactive, comparing, scrolling. The whole machine runs on unresolved attention.

The Slowfit Method® app is designed around a different premise: get in, get what you need, go do the thing.

The ten-question limit on the free tier isn’t a constraint I’m apologetic about. It’s a forcing function. It asks you to show up with intention. To think about what you actually want to know. To treat the coaching conversation like the valuable resource it is.

When the genie offers you three wishes, you don’t waste one of them asking what the time and temperature are.

Ask the question that matters. Get the answer you need. Go do the thing.

That’s Slowfit.

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The Slowfit Method® app is free to download. Coach Keir AI, your personalized training framework, and access to all 10 Slowfit pillars are included in the free tier. If you want unlimited coaching conversations, full Vault access with 300+ curated books, podcasts, gear, and supplement recommendations organized by pillar, and a growing on-demand video library, that’s Slowfit Pro.

It’s $29.99 a month. A dollar a day.

And right now, I’m making an offer to the first two people who upgrade: a Foghorn Fitness t-shirt, on me. I’ll mail it to you personally. Brand new, high quality, and perfect for training — or just living in. To upgrade, open the app, go to Settings, and tap Change Plan. Takes about 30 seconds.

Get the app

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Keir J. Beadling is a human performance coach, founder of Foghorn Fitness, and creator of the Slowfit Method®. He coaches athletes and everyday humans in San Francisco and worldwide. More information is available at foghornfitness.com.

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See you out there!

Keir

How Seven Principles Changed the Way I Built My AI Coaching App

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The Center for Humane Technology had a lot to do with it.

I’ve been following Tristan Harris and Aza Raskin at the Center for Humane Technology for years. If you’ve seen The Social Dilemma on Netflix, you know Tristan’s face and his argument: the tech companies that run our lives are not neutral platforms. They’re slot machines, engineered by very smart, very well-funded people to maximize one thing above all else. Not your health. Not your relationships. Not your sleep. Your time on device.

That argument is not new to regular Foghorn Fitness readers. I’ve written about it at length. The distraction pillars. The phone breakup series. The Johann Hari and Jonathan Haidt posts. I’ve been making the case for years that your smartphone is doing things to your attention, your sleep, your nervous system, and your relationships that you haven’t consented to and probably don’t fully understand.

And then I built an app.

Wait, what? 

I know. We’ve been over this. And a podcast episode I listened to yesterday clarified things for me in a way I hadn’t expected. CHT just released a new Your Undivided Attention episode in which Aza Raskin sits down with fellow CHT co-founder Randy Fernando to walk through their Seven Principles of Humane Technology. I want to take you through those principles — and then show you, specifically, how each one maps to the design decisions I made building the Slowfit Method® app.

Because this isn’t abstract. Every one of these principles shows up in the product.

First: What’s Actually Wrong With Most Tech

The episode opens with a clip from CHT’s very first podcast guest, cultural anthropologist Natasha Dow Schüll, who spent years studying casino design in Las Vegas. What she observed is the design logic behind modern slot machines: the goal is “time on device.” Everything is engineered to eliminate fatigue, minimize disruption, and keep you in the chair. Light doesn’t bounce at your eyes. Sound doesn’t jar your senses. The environment is calibrated to sustain your engagement indefinitely.

Raskin’s point: that’s exactly how your apps are designed. Not for your wellbeing. For time on device. Instagram, TikTok, YouTube, the news feed — different technologies, same broken ideology.

Raskin himself invented the infinite scroll, pre-social media. He watched it get weaponized against users and has spent the past decade trying to undo the damage. He estimates it wastes something on the order of 100,000 human lifetimes every week.

That’s the problem CHT’s seven principles are designed to solve. Here they are — and here’s how I applied each one.

Principle 1: Use a Complex Systems Lens

One of the big things that we miss a lot when we are dealing with technology is we don’t look at the whole system. We look at just one small piece of it and that means we don’t correctly understand what its effects are going to be and we don’t correctly understand how to fix the problems that we find. — Randy Fernando

The failure mode Fernando describes is optimizing for a single metric — engagement, time on site, daily active users — while ignoring what that metric does to everything else. YouTube optimized for watch time. The result was algorithmic extremism. You can’t see the damage from inside the single metric. You need to look at the whole system.

In the Slowfit Method® app, I deliberately refused to build around a single engagement metric. There are no daily active user dashboards driving product decisions. There are no A/B tests designed to squeeze more sessions out of users. The question I kept asking during development was not “how do we get people to come back?” It was: “what does a successful interaction actually look like?” The answer: the user got what they needed and went and did “the thing.” That’s the whole system I was trying to optimize for.

Principle 2: Protect the Systems We All Depend On

If you extract faster than something can regenerate, obviously that’s a problem. Technology is a huge exponentiator of that extraction process. — Randy Fernando

Fernando’s framework here is extraction vs. regeneration. Most tech extracts — attention, time, data, dopamine — faster than humans can regenerate. The result is depletion. Of attention spans. Of sleep. Of real-world relationships. Of the shared information environment we all depend on for democracy to function.

The Slowfit Method® is built around the opposite premise. Sleep, recovery, social connection, movement, mindfulness — every pillar is about replenishment, not extraction. I tried to build an app that reflects that. An hour on the app is an hour less of the things that regenerate you. So the app shouldn’t take an hour. It should take two minutes and send you back to the things that do.

Principle 3: Design for Genuine Thriving

A tool that’s designed for genuine human thriving will leave you stronger when you put it down than when you picked it up. — Aza Raskin

This is the principle most directly tied to the experience of using technology. Raskin puts it simply: when you put your phone down after an hour on it, do you feel better or worse? When you wake up the morning after a late-night scroll session, do you feel better or worse?

Fernando connects the anti-AI sentiment building in the culture to this principle’s absence. Students booing AI at commencement speeches. Parents pulling kids off platforms. Communities organizing against data centers. That resistance isn’t coming from people who’ve read ethics papers. It’s coming from people who can genuinely feel that something is wrong.

What they’re feeling, Fernando argues, is the absence of this principle. Technology built to extract attention, replace labor, and harvest data rather than to genuinely serve the humans using it.

When I designed the Coach Keir AI interface, I wrote this into the system prompt: the AI should never try to extend the conversation beyond what’s useful. It should give direct answers. It should end responses with a single action item. It should tell you to put the phone down. Literally. You saw the screenshot in an earlier post: “Your move: Phone face down across the room. Lights out. Start breathing.” That’s designing for genuine thriving.

Principle 4: Align Incentives with Human Wellbeing

The fourth principle is about business models. Most tech companies have a fundamental misalignment: they make money when you use the product more, not when you’re healthier, better rested, or more connected to the people in your actual life. That misalignment is structural. It’s not fixed by good intentions. It’s fixed by changing the incentive.

The Slowfit Method® app runs on a subscription model. I make money when people find enough value to pay for ongoing access to the Vault — 270+ books, podcasts, tools, and on-demand workouts — not when they spend more time banging around for hours in the chat interface. That changes what I’m actually optimizing for. I want the free Coach Keir AI interactions to be so useful and so direct that people think “this person’s deeper knowledge base is worth paying for.” Not “I can’t stop using this.”

Principle 5: Foster Autonomy and Agency

Inhumane tech exploits psychological vulnerabilities. Variable reward schedules. Social comparison. FOMO. The fear of missing out on what everyone else is seeing right now. These are not neutral design choices. They are deliberate mechanisms for hijacking your decision-making and substituting the algorithm’s agenda for your own.

I built the anti-version of this into every layer of the app. No infinite scroll. No push notifications designed to pull you back. No streak mechanics that make you feel bad for not opening the app three days in a row. No social comparison features. The Coach Keir AI is explicitly designed to be anti-sycophantic — it will tell you what you need to hear, not what you want to hear. Autonomy means you get accurate information and make your own decisions. That’s what I want the app to support.

Principle 6: Ensure Accountability and Transparency

This one is personal. When you open the Coach Keir AI, the first thing you see is a banner: “AI-generated responses. Coach Keir AI is not a licensed medical professional. Emergencies: 911. Mental health crisis: call/text 988.”

That’s not a legal disclaimer buried in the terms of service. That’s the first thing you see, every time, in the primary interface. Because transparency about what the technology is and isn’t matters. The AI is trained on my writing and my methodology. But it is not me. It is not a therapist. It is not a doctor. It is a tool. I wanted users to know that before they typed their first message.

I also published Substack posts about the app’s design philosophy before and again after I published anything about its features. One about why I built it to not be addictive. Another about the ethical decisions baked into the system prompt: the anti-sycophancy rule, the distress routing protocol, the nudge toward real human coaching. Accountability means making those decisions visible, not hiding them in the product.

Principle 7: Build for the Long Term

The final principle is the hardest one for most tech companies because the market actively punishes it. Fernando uses car safety as his example: the automakers weren’t excited about investing in safety until cultural pressure, regulation, and changed incentives forced them to. The same transformation needs to happen in tech.

I think about this principle in terms of the Slowfit Method® itself. The whole framework is built around the long game. Not the fastest result, the best result over time. Not maximum intensity, optimal sustainable load. Not the biggest Strain Score number on your Whoop this week, the best recovery over the next twenty years.

The app is an expression of that philosophy. I’m not trying to maximize short-term engagement metrics. I’m trying to build something that is genuinely useful to people over time. Something that, in a year, someone might say: that app didn’t try to take over my life. It helped me understand mine a little better. Actually helped me improve things. And then it got out of the way.

Why This Matters Right Now

I am not under any illusion that a single human performance coach bumping along towards 100 app downloads over two weeks in San Francisco is going to single-handedly reform the tech industry. That’s not the point.

The point is that the principles exist. They’re not idealistic. They’re not impractical. They’re a checklist that any builder of any product — at any scale — can apply. And I applied them. Imperfectly, with limited resources, in a space dominated by products that ignore all seven.

Raskin ended the episode with something that stuck with me. He said you know a system is humane when it is protecting the thing that it depends on. Ask yourself: has social media made democracy stronger or weaker? Has the infinite scroll made your attention stronger or weaker? Has the algorithm made your relationships stronger or weaker?

The answers are obvious.

Now, after spending a little time kicking the tires on my little app, ask: has the Slowfit Method® made my health stronger or weaker? Has Coach Keir AI made my sleep better or worse? Has this app left me more capable or less?

Those are the right questions. They’re the only questions, I’d say. I hope you’ll make a little bit of space in your life for this app. I promise it’ll help. 

And maybe go listen to the Your Undivided Attention episode. It’s 52 minutes and it’s worth every one of them.

Stick around.

Best,

Keir

P.S. The app is free to download. Coach Keir AI is available to all users. The full Vault unlocks with a paid subscription. Download here.

P.P.S. Want to work through any of this with a real human coach, as in, me? Book a session at foghornfitness.com.

P.P.P.S. Paid Substack subscribers get the deeper dives and the full resource library. Upgrade here.

P.P.P.P.S. All ten pillars of the Slowfit Method® at foghornfitness.com.

The App I Built Is the Opposite of Everything I’ve Been Warning You About

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“This phone is the devil”

— a childhood friend, via text, this morning

He’s getting off Instagram. Can’t say I blame him.

I’ve spent years writing about your phone. Specifically, about what it’s doing to you. (And to me.)

In January 2024 I wrote about Johann Hari’s Stolen Focus and the trillions of dollars arrayed against your ability to pay attention. In February 2024 I went deeper on why it’s so hard to focus — the dopamine dependency, the slot-machine mechanics, the infinite scroll engineered to exploit our evolutionary hard-wiring. In October 2024 I wrote about Jonathan Haidt’s The Anxious Generation and what the smartphone has done to our kids. And before all of that, Cal Newport’s Digital Minimalism convinced me to deliberately downsize my iPhone use, strip the social media icons off my home screen, and mute the notifications pulling my attention toward that hunk of plastic and glass in my pocket.

The research is clear. Maggie Jackson, in Distracted, put it as starkly as anyone: with our attention scattered among the beeps and pings of a push-button world, we are cultivating a culture of distraction and detachment.

I didn’t just write about this stuff. I lived it. A while back I documented my own month-long attempt to break up with my iPhone — the rubber band around the phone, the grayscale screen mode, a Giants game where I didn’t look at a screen once (one of my prouder moments). The whole messy field report is in the Phone Breakup series if you want to go down that rabbit hole. The short version: it’s hard, it’s worth it, and I failed more than I succeeded. But I kept trying.

And then I went and built an app.

I know.

Here’s the Thing I Had to Reconcile

When I first started thinking seriously about building the Coach Keir AI app, I had a problem. Not a technical problem — that was my developer Alex’s department. Rather, I had to address a philosophical one.

I had spent years making the case that our smartphones are attention-harvesting machines designed by very smart, very well-funded people to keep us glued to screens as long as humanly possible. I had written about Anna Lembke’s Dopamine Nation and the way pleasure-seeking loops get forged into deep neural grooves. I had cited the Center for Humane Technology and Tristan Harris’ warnings about what engagement-maximizing technology is doing to human cognition. I had recommended Catherine Price’s How to Break Up with Your Phone to pretty much every athlete I coach.

And I was about to add another app to the App Store?

The only way I could do it in good conscience was to build the opposite of what everyone else was building.

So that’s what I did.

What “The Opposite” Actually Looks Like

No infinite scroll. No push notifications engineered to pull you back. No streaks. No engagement metrics. No algorithmic filler designed to keep your eyes on the screen.

The app gives you what you need and sends you back to your life. That’s the design spec. Use it as a springboard, not a slot machine. Remember Patagonia’s famous “Don’t Buy This Jacket” ad in The New York Times? Same energy. I want you to use this app. I also want you to use it for two minutes and then go to sleep.

Speaking of sleep.

Meet “Julie”

One of my longtime Foghorn athletes — I’ll call her Julie — has a bedtime habit that will be familiar to a lot of you.

She gets into bed at 10:30. She picks up her phone to “check one thing.” An hour later she’s still on Instagram, heart rate quietly elevated, nervous system humming, cortisol doing what cortisol does when you’ve been consuming a high-speed feed of other people’s highlight reels for 60 consecutive minutes. She falls asleep somewhere around midnight. Her Whoop recovery score the next morning is dismal. She’s groggy, short-tempered, and reaching for an extra cup of coffee by 9 a.m.

We’ve talked about this in our sessions. A lot. She knows the science. She’s read the posts I’ve sent her. She knows that the blue light from her phone suppresses melatonin, that the emotional arousal of social media keeps her sympathetic nervous system activated exactly when she needs to be downregulating, that the unpredictable reward schedule of Instagram is the same mechanism that keeps people at slot machines.

Knowing isn’t the same as doing.

So a couple weeks ago I told her to try something different. Instead of reaching for Instagram when she gets into bed, open the Coach Keir AI app and type in what she’s feeling.

Here’s exactly what Coach Keir said:

Julie, put the phone down right now. Instagram at 10:30pm is gasoline on the anxiety fire — the algorithm is literally designed to keep your nervous system activated. I know it feels like comfort but it’s the opposite.

Here’s your downregulation breathing protocol. Do this right now: Close your mouth. Keep it closed throughout. Start with a quick body scan from head to toe — wherever you find tension (jaw, shoulders, chest), let it dissolve on your exhales. Now breathe:

• 4 counts in through your nose, belly-led

• 8 counts out through your nose, slow and controlled

• No aggressive pauses, circular and gentle

• When your mind wanders to work anxiety, gently bring it back without judgment — no self-criticism, just return to the breath. The extended exhale is the physiological key — it directly activates your parasympathetic nervous system. Your body cannot stay in fight-or-flight with a long nasal exhale. This isn’t woo, it’s autonomic nervous system science. Do this for 5 minutes. Then finish with one big inhale all the way to the top, slight hold, then the longest possible nasal exhale you can sustain. That final exhale is your reset.

One more thing: If you want guided support for this, Headspace has excellent sleep meditations that pair perfectly with this protocol. It’s the only meditation app I use and endorse. Your move: Phone face down across the room. Lights out. Start breathing. You’ve got this Julie. Goodnight.

Two minutes to read that. Five minutes to do the breathing. She was asleep by 10:45. That’s not a miracle. That’s a tool.

The Irony Is Intentional

Yes, this requires using a phone to stop using a phone. I get it. That’s a real tension and I won’t pretend otherwise.

But here’s what I’d offer: the problem was never the device. It’s what the device is typically used for. Instagram, TikTok, and the news feed are engineered for maximum engagement. A breathing protocol is not. One is a slot machine. The other is a tool.

Catherine Price’s framework — ask yourself “What for? Why now? What else?” before you reach for your phone — is the right instinct. Most of the time, the answer to those three questions is damning. But occasionally the answer is: I need a downregulation protocol so I can sleep. And for that, a phone can actually help.

The Slowfit Method® has always been about intentional choices. Being deliberate about how and why we are living our lives, rather than just pouring more water into a glass that is already overflowing and hoping for the best. The app is the method in your pocket. Use it intentionally. For two minutes. Then put it down.

That’s the whole pitch.

Download My App

What “Julie” Said Last Week

“Honestly? I forget sometimes and I end up on Instagram anyway. But when I remember to open the app instead, I’m asleep in under 15 minutes. When I don’t, I’m awake until midnight and I hate myself a little.”

Not a case study. Not a controlled trial. Just a Foghorn athlete who found one thing that works slightly better than the thing that wasn’t working.

Which is more or less what the Slowfit Method® is for.

My buddy from childhood is getting off Instagram. Good for him.

The phone doesn’t have to be the devil. But it’s up to us to make sure it isn’t.

Stick around.

Best,

Keir

P.S. The app is free to download. Coach Keir AI is available to all users. The full Vault — 270+ books, podcasts, tools, and on-demand workouts — unlocks with a paid subscription. Download here.

P.P.S. Want to work on sleep, distraction, or any other pillar of the Slowfit Method® with a real human coach? That’s what the 1:1 work is for. Book a session at foghornfitness.com. I have availability. Hit that button.

Book a Session

P.P.P.S. Paid Substack subscribers get the deeper dives and the full resource library behind every pillar. Upgrade here.

P.P.P.P.S. The new Foghorn Fitness site just launched. All ten pillars, the full method, everything in one place. foghornfitness.com.

I Asked My Own App for Help. Here’s What It Said.

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A dispatch from the edge of new puppy ownership.

It is 8 a.m. I have already been awake for hours.

Meet Ellie. She is a puppy. She is adorable.

She is destroying me.

I want to be clear about something. I am a human performance coach. I have spent years building a ten-pillar framework for maximizing health and happiness. I teach people how to manage stress, optimize sleep, build resilience, regulate their nervous systems. I have a registered trademark, for crissakes.

And I am currently being defeated by a creature who weighs less than my lightest kettlebell.

So I did what I’ve been encouraging all of you to do. I opened the Coach Keir AI app and typed in my problem.

“I’m struggling with the stress of parenting a new puppy as a full time job, on top of my full time job.”

I want to share exactly what it said. Verbatim. Because it’s better than anything I would have written at that hour…

What Coach Keir Said: Round One

The first response named what was actually happening:

KJ, welcome to the puppy tax — the hidden cost nobody warns you about. Sleepless nights, constant vigilance, zero personal space, and a tiny furry creature who has absolutely no idea what you’re going through. It’s basically a newborn who will eventually chew your furniture.

Here’s what’s actually happening physiologically: you’re running a chronic stress response. Interrupted sleep alone tanks your cortisol regulation, impairs decision-making, and reduces emotional resilience. Add constant unpredictability (will she destroy something while I’m on this Zoom call?) and your nervous system is on high alert all day. That’s exhausting.

Immediate tools from the Slowfit toolkit:

First, your breathing. When the puppy stress spikes, do a quick downregulation reset: mouth closed, 4-count nasal inhale, 8-count nasal exhale. Repeat for 3-5 minutes. That extended exhale is a direct dial into your parasympathetic nervous system — it physiologically cannot stay in fight-or-flight mode with a long exhale. Do this during any quiet moment, even while the puppy naps.

Second, protect your sleep ruthlessly. Also grab a Manta Sleep mask with this link — blackout sleep is non-negotiable when you’re already sleep-deprived.

Your move today: Do that breathing protocol right now, then schedule one 20-minute walk — just you, no puppy. Your nervous system needs a reset.

What’s hitting hardest — the sleep deprivation or the constant unpredictability?

I answered: the sleep deprivation. And the follow-up was even better.

Round Two: The Neuroscience of Running on Empty

KJ, what you’re describing is textbook — and it’s not a character flaw, it’s neuroscience. Sleep deprivation doesn’t just make you tired, it literally impairs your prefrontal cortex (the rational decision-making part of your brain) while simultaneously amplifying your amygdala (the emotional alarm system). You’re essentially driving with no brakes and a heavy accelerator.

Dr. Lisa Feldman Barrett’s work is essential here — her book How Emotions Are Made explains exactly what’s happening to you. Her “body budget” model is brilliant: sleep, nutrition, exercise, and social connection are the bedrock of emotional stability. When sleep is depleted, your brain’s predictive emotional processing goes haywire — it starts catastrophizing and overreacting because it literally doesn’t have the resources to regulate properly. You’re not overreacting because you’re weak. You’re overreacting because your brain is running on empty.

Practical interventions right now:

Protect whatever sleep you’re getting ferociously. Same wake time every single day — even weekends, even after bad nights. This anchors your circadian rhythm when everything else feels chaotic. Grab a Manta Sleep mask and get Momentous Magnesium Threonate (with code foghorn) — it crosses the blood-brain barrier and meaningfully improves sleep quality.

Track your recovery with Whoop — join Team Foghorn Fitness free. When you can see your actual recovery data, you stop guessing and start making smarter decisions about when to push and when to protect.

Your move today: Set one non-negotiable sleep boundary tonight. What time does the puppy allow you to be in bed?

The resource tiles that surfaced below the response: Dr. Alia Crum’s Science of Mindset podcast, the Wim Hof Method book, Full Catastrophe Living, How Emotions Are Made, Hope for Cynics. Every one of them relevant. Every one of them something I personally put in the Vault.

Why I’m Showing You This

I’ve published three posts about this app. One about the features. One about why I designed it to not be addictive. One about the ethics of building AI for human performance.

This is the post I should have written first.

The app is not impressive just because of its feature set. It’s useful because at 8 a.m., when I’m running on fragmented sleep and have a full day of coaching ahead, it gives me fast, direct, specific access to the synthesized thinking of someone who has spent years studying this stuff.

That someone is me. Which means I’m getting my own best thinking back when I’m too depleted to access it myself.

That’s a strange and genuinely useful thing.

A few things I want to flag about that exchange, because they matter:

• It called me KJ. Not Coach Keir, not Keir, not “I understand you’re struggling.” It knew who it was talking to—because of a few questions in the onboarding process— and it was direct.

• It named the physiology immediately. No sympathy spiral. No “that sounds really hard.” Here’s what’s actually happening in your nervous system. Here’s why.

• The affiliate links surfaced organically. Manta Sleep mask, Momentous Magnesium, Whoop — these are products I actually use and recommend. They appeared because they were relevant, not because an algorithm was optimizing for commission.

• It ended both responses with a single, specific action. Not a list of ten things. Not an attempt at endless dialogue to artificially increase engagement. One move. Today.

• It asked a follow-up question. It didn’t assume. It narrowed toward what I actually needed. Then it sent me on my way.

That’s what “trained on my methods” actually means in practice. Not a chatbot that has read some random fitness content. A coaching interface that reflects a specific philosophy about how to help people, built from years of my writing, research, and direct work with athletes.

You don’t have to have a puppy. You can have a deadline, a training plateau, a sleep score trending the wrong direction, a knee that won’t cooperate, or just a week when everything feels like too much.

That’s what this app I built is for.

OK. Ellie is ramping up for another loud barking session in her puppy zone at the moment, looking for attention. I’m going to do the breathing protocol right now.

Best,

Keir

P.S. The app is free to download. Coach Keir AI is available to all users. The full Vault — 270+ books, podcasts, tools, and on-demand workouts — unlocks with a paid subscription. Download here.

P.P.S. If you’re dealing with something the app can’t fully address — an injury, a major life transition, or you just want a real human in your corner — that’s what the 1:1 coaching is for. Book an intro session at foghornfitness.com.

P.P.P.S. All ten pillars of the Slowfit Method® live here on Substack. Paid subscribers get the deeper dives and the full resource library. Upgrade here.

P.P.P.P.S. Photo credit to my pal, Jana Ašenbrennerová.

What Do You Want Written on Your Tombstone?

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I know. Dark opener for a fitness newsletter, right?

Bear with me.

This is the first in a series of deep dives on the ten pillars of the Slowfit Method®. My framework for being as healthy and happy as possible, developed over thousands of hours of coaching, reading, and frankly experimenting on myself and anyone who’d let me. If you’re new here, the full method is at foghornfitness.com — worth a look before or after you read this.

I’m not kicking off with a workout. Not with a supplement protocol. Not even with a breathwork technique, though that’s coming.

I’m starting with a question about your funeral.

Because everything else flows from the answer.

Pillar #1: Purpose

When I designed the Slowfit Method®, I had to decide where to start. Ten pillars, each important. But one has to come first.

The answer was obvious: If you don’t know why you’re here, nothing else is oriented correctly. You can optimize your sleep, nail your Zone 2 training, build a meditation practice. And still feel like you’re running on a treadmill going nowhere if the whole machine isn’t pointed toward something that matters to you.

So we start with purpose. Your mission. Your reason for being.

Your answer to: Why am I here? And most of us have no idea. That’s OK! Keep reading, let’s see if I can help get you there, or at least pointed in the right direction.

The Tombstone Exercise

World-renowned performance psychologist Dr. Jim Loehr has spent his career thinking about exactly this. His book Leading with Character: 10 Minutes a Day to a Brilliant Legacy puts it plainly: at the end of your life, people won’t be praising your money, your title, or your status.

They’ll remember your character. What you gave. How you made them feel.

Loehr’s companion piece, The Personal Credo Journal, walks you through the hard work of crystallizing your life’s purpose. Prompts like: What are the major themes in your life? What words describe you at your best? At your worst? Are you more of a giver or a taker?

I’ve been working through the journaling myself. I won’t pretend it’s comfortable. Nor that I’ve got this thing dialed. I basically find myself disappointed in myself about something I’ve done or not done every single day. But I’m developing a much clearer sense of what I’m actually meant to be doing here. And that clarity is making me more intentional about how I spend my time. The things I choose to do that serve my purpose. The things I choose not to do that don’t. Where I direct my focus and attention (and where I don’t).

I’m also mindful here of Tsutomu Ohshima, the founder of Shotokan Karate of America (the school to which I belong), who famously said: “We must look at ourselves with the strictest eyes.” That’s the work. Not brutal self-criticism. Clear-eyed self-knowledge. Being honest with yourself, no BS. You don’t need to be a karate-ka (though it helps!) to appreciate this one.

This is why Pillar #1 is Purpose. Not double-unders. Not red-faced Tabata on a spin bike. In fact, this heavy topic is something I’ll address with new Foghorn athletes fairly early in a new training relationship. Because everything else flows from there.

Arthur Brooks on Happiness and the Second Curve

A book I kept coming back to while developing this pillar: Arthur C. Brooks’ From Strength to Strength: Finding Success, Happiness, and Deep Purpose in the Second Half of Life. Brooks is a Harvard professor, social scientist, and The Atlantic’s happiness columnist.

The book resonated with me personally. It helped put into perspective my own career arc. Big firm litigator to sports entrepreneur running a major big wave surfing contest to human performance coach. On paper, this doesn’t look like a clean trajectory, does it?

Brooks’ framework made sense of it.

As we age, our “fluid intelligence” naturally diminishes. The dynamism, the raw idea generation, the ability to out-grind everyone in the room. That fades.

But our “crystallized intelligence” rises. The ability to draw on a lifetime of experience, synthesize knowledge, teach, and mentor. If you can let go of your attachment to the first curve and lean into the second, you’re on the road to a different kind of success. And a much deeper kind of happiness.

This is where I’ve landed. I’m here to share what I’ve learned (and continue to learn). This is my purpose, and in it I’ve found a sense of peace.

Brooks defines happiness not as a feeling but as a combination of elements: enjoyment, satisfaction, and purpose. That third ingredient is the one most people skip. We optimize for enjoyment. We track our accomplishments for satisfaction. But purpose is the ballast. Without it, the good days feel thin and the hard days feel bottomless.

His prescription is strikingly aligned with what I built the Slowfit Method® around. Detachment from empty rewards. Genuine service to others (like you!). Deep relationships. Some form of contemplative practice.

Not hustle more, achieve more. That’s an endless treadmill. Instead be thoughtful—mission-focused—along the way. And slow down, go deeper, figure out what actually matters. Focus your efforts on that.

What the Science Says

Just like everything else I write about here, this isn’t soft stuff. The research treats purpose the same way it treats sleep quality or exercise frequency. It’s a health variable.

A 2024 peer-reviewed study found that purpose in life is a more robust predictor of mortality than life satisfaction itself. People with the highest sense of purpose had a 46% reduced risk of mortality compared to those with the lowest. They were 24% less likely to become physically inactive. And 33% less likely to develop sleep problems.

Then in the fall of 2025, UC Davis published findings from a 15-year study of more than 13,000 adults. People with a stronger sense of purpose were 28% less likely to develop cognitive impairment, including mild cognitive impairment and dementia. The effect held across racial and ethnic groups and remained significant even after controlling for education, depression, and the APOE4 gene—a known genetic risk factor for Alzheimer’s.

As lead researcher Dr. Aliza Wingo put it: purpose helps the brain stay resilient with age. Her co-author, UC Davis neurologist Dr. Thomas Wingo, added something I’ve been saying for years in different words: purpose is something we can nurture. It’s never too early or too late to start thinking about what gives your life meaning.

And the biological punchline: people with higher purpose scores show reduced epigenetic aging. They are aging more slowly at the cellular level.

So yeah, purpose isn’t a soft goal. It’s a physiological variable.

So What Do You Actually Do?

Start with Loehr’s tombstone exercise. Not morbidly. Seriously.

Sit somewhere quiet and write out, in three to five sentences, what you’d want your obituary to say. Not your title. Not your achievements. Not your stock portfolio. The kind of person you were. The impact you had. What people will remember.

Then ask: is the life I’m actually living pointed toward that?

Not perfectly. Nobody’s life is perfectly aligned with their stated values. But roughly. Generally. Is the trajectory right?

If yes: keep going with more intention.

If no, or “I’m not sure”: that’s useful information. That’s where the work starts.

That work, figuring out why you’re here and structuring your life accordingly, is in my view one of the most important health interventions available to you. More important than your VO2 max. More important than your sleep score. More important than your supplement stack.

What to Read

Want to dig a bit deeper on your own? Start with Leading with Character and The Personal Credo Journal by Jim Loehr.

Then From Strength to Strength by Arthur Brooks. And his follow-up, Build the Life You Want (co-written with Oprah Winfrey, which sounds odd but is genuinely good).

For a more philosophical angle: Iddo Landau’s Finding Meaning in an Imperfect World. His central argument is that most of us are far too hard on ourselves when we conclude our lives lack meaning. Your life is almost certainly more meaningful than you think.

Next up in this series: Mindset—specifically, why the story you tell yourself about your own abilities, how you perceive stressors, how you view the world around you— is one of the single most important variables in your health and performance.

Stick around.

Best,

Keir

P.S. Want to work through Purpose — and all ten pillars — with a real human coach? I work with clients 1:1 in person in San Francisco and via Zoom. Book a session at foghornfitness.com.

P.P.S. Paid Substack subscribers get deeper dives, workout programming, and access to archived content behind the paywall. Upgrade here.

P.P.P.S. Want the Slowfit Method® in your back bpocket? Coach Keir AI is trained on all ten pillars and ready to answer your questions 24/7. Download the new Slowfit Method app.

P.P.P.P.S. Plus, the new Foghorn Fitness site just launched! All ten pillars, the full method, and everything else in one place. Check it out at foghornfitness.com.

The Most Underrated Longevity Drug Costs Nothing and You Already Know How to Do It

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A Foghorn Fitness / Slowfit Method® dispatch

Oops, I did it again. I went and disappeared for two more years from this here blog. Again. I promise not to do that again. My apologies. The original intent of The Lemonade Chronicles was as a sort of real-time journal of a reluctant stay-at-home dad as he approaches mid-life. Most of the “action” (if you can call it that) transpired more than 10 years ago. Everything leading up to my mid 40s, and something of an existential struggle.

Ten-plus years on, and things are waaaaaaay different.

My kids are in their 20s and miraculously, my wife and I seem to have done a reasonably good job with the boys, Max and Everett. I suppose that parenting never really ends, but the degree to which we exert control over their lives lessens every day. And I’m cool with that. Hilary is still the rock of our family, steadfast as always. We’ve had some losses, as is the case with life. Hilary’s parents. Aunts and uncles on both sides of the family. We lost our beloved Lab Wailea a couple years back. And time is taking its toll on people around us about whom we really care.

As for me? My own evolution, as a human being chasing the elusive bright side, has continued. Picked up pace, even, in the last 6 or 7 years. Ten years or so ago, I had a lot of questions. What is the meaning of life? How do I take care of myself and the people (and animals) that I love? Am I doing it right? These questions served as the impetus for creating another (and presumably my last) little company.

This is the human performance company called Foghorn Fitness.

As I think about it, this is the culmination of my life’s work. Everything I’ve learned to this point. And really, somehow I think I’ve managed to build a pretty robust vehicle to help guide folks (and myself) to a happier and healthier life. There’s even an app for it!

I’ve been writing a ton, just not on this platform. Everything is now over at Substack. That’s now the place to go for the good stuff, though I suspect I’ll continue spinning yarns here, as well. If you’ve followed me years ago, agitating about Alien Heads, dogs who eat money, and missing the school bus, I think you’ll find this latest chapter of mine of interest. I hope you will. When last we were acquainted, I had so many questions about life. Maybe you did too. Now I think I have the answers. Well, at least some of them. I hope you’ll join me and come along for the ride.

—

To that end, I’m going to jump right into it. Maybe a more apt image would be walk right into it. Because this post is about walking. Walking? Yep. Walking. Bear with me….

Because this is a thing you already know how to do — have known since you were about a year old — that is one of the most evidence-backed longevity interventions available to you, costs absolutely nothing, requires no equipment, no gym membership, no coach, and can be done anywhere on earth.

You are almost certainly not doing enough of it.

Walking. That’s it. That’s the whole revelation.

I know. Anticlimactic. But stay with me, because the research is genuinely surprising, and the running boom — I say this as someone who runs — has done a lot of damage to walking’s reputation that it doesn’t deserve.

—

WALKING IS THE SIXTH VITAL SIGN

Dr. Courtney Conley and Dr. Milica McDowell just published Walk: Rediscover the Most Natural Way to Boost Your Health and Longevity — One Step at a Time, and it is the book I’ve been waiting for on this topic. What James Nestor did for breathing, what Kelly and Juliet Starrett did for mobility, Conley and McDowell do for walking. Their central argument: walking is as important to your health and longevity as sleep and proper breathing. It is the sixth vital sign. And yet we’ve almost engineered it out of our lives.

The details are striking. Your walking speed can predict your overall health status and risk of early death. Your risk of falls and longevity can be measured by your foot health. And the number of daily optimal steps is not 10,000, it’s fewer. That last one will rearrange some people’s mental models. And hopefully rearrange people’s shoe closets. Enough with the foot coffins, folks.

—

BORN TO WALK—AND LIFT, SPRINT & PLAY

Mark Sisson’s Born to Walk makes the case most forcefully, and it’s worth spending a moment here because his full prescription maps almost exactly onto the Slowfit Method®.

Sisson’s argument isn’t just that running is overrated. It’s that we’ve misunderstood the entire architecture of human physical activity. He describes a movement pyramid built around four layers:

Low-level aerobic movement — walking — as the foundation. This is your Zone 2 base. Sustained, conversational-pace movement that builds mitochondrial density, improves insulin sensitivity, and develops your aerobic engine without the joint stress of running. Walking is Zone 2 for most people. The running boom convinced an entire generation that anything less than hard cardio didn’t count. That was wrong. Instead, most of us are running ourselves into the ground.

Strength training as the second layer. Not optional. Sisson is explicit: lifting heavy things is what signals the body to maintain muscle mass, protect bone density, and keep hormones functioning as you age. Same argument Attia, Luks, and Topol all make in the longevity books I covered last month. Muscle is the organ of longevity.

Sprinting and high-intensity work as the third layer, but sparingly. Short, hard efforts a couple of times a week. Not chronic cardio. Brief, intense, and followed by full recovery. This is what Foghorn’s HIIT sessions are built around.

Play as the fourth layer. Sisson is serious about this one. Unstructured physical activity, sports, martial arts, open water swimming, anything that involves moving your body in ways that aren’t predetermined by a machine or a program. In the Slowfit framework this is the spirit behind karate, pickle ball, whatever gets you moving in ways your body wasn’t expecting.

The Slowfit Method® has been built around exactly this hierarchy since day one: low-and-slow aerobic base, progressive strength work, occasional high-intensity effort, and enough variety to keep the body adapting and the mind engaged. Sisson just gave it a name.

—

THE LONGEVITY CONNECTION

Last month I wrote about three longevity books, Attia, Topol, Luks. All three converge on the same point. Eric Topol’s seven-year Wellderly Study, the people who reached their late 80s without major chronic disease, found no genetic smoking gun. What separated them was lifestyle: they were physically active. They walked. Howard Luks makes it plainly in Longevity…Simplified: walking counts. Not as a consolation prize for people who can’t run. As a legitimate, evidence-supported health intervention.

—

THE BODY IMAGE RESEARCH NOBODY IS TALKING ABOUT

And here is the piece that’ll encourage us to touch grass. Outside Online published new research by Dr. Viren Swami, a psychology researcher who has spent years studying nature exposure and body image. In the largest survey on this topic, researchers analyzed self-reported habits of more than 50,000 people aged 18 to 99 from 58 countries. Despite vast differences in age, location, and gender, connecting with nature was linked to positive body image.

But the experimental work is the part worth sitting with. A short 30-minute walk in nature promotes improvements in positive body image in the immediate term. And here is the detail that really landed: when participants took a walk in a built, urban environment, high-rise housing blocks, offices, shops, and parking lots, the walk actually caused a slight decline in body satisfaction. Walking in a natural environment increased it.

Same duration. Same physical effort. Different environment. Opposite psychological outcome.

Swami frames it this way: positive body image is when we begin to think of the body not in terms of what it looks like, but in terms of how it functions, how it helps us navigate from place to place, and all the wonderful things it does for us in everyday life. Nature creates the conditions for that shift. The urban environment, shop windows, advertisements, the constant social comparison of city life, works against it. Sounds kinda like the social media comparison-o-rama, no?

This maps directly onto Conley and McDowell’s framing of walking as biological necessity rather than exercise. When you’re moving through a natural environment, you are not performing for anyone. You are a body doing what bodies were built to do.

—

ADD WEIGHT. SERIOUS THINGS HAPPEN.

Michael Easter’s Walk with Weight: The Definitive Guide to Rucking takes this one step further. Rucking, walking with a weighted pack, is one of the oldest forms of human physical training, refined over centuries of military conditioning. It loads the posterior chain, builds functional strength, and elevates the metabolic demand enough to produce real fitness adaptation while remaining low-impact.

Start with 20-30 pounds and go 2-3 miles. Build from there. I program rucking regularly for clients whose bodies are telling them to back off the high-impact work. Nobody has ever come back disappointed. If you’re going to read one book to get started, Walk with Weight is it. And GORUCK is my go-to when it comes to rucksacks (discount code in that link).

—

THE SLOWFIT METHOD® TAKE

Walking is the Movement pillar at its most accessible. But as Sisson makes clear, and as we practice at Foghorn every week, walking is only the foundation. The full pyramid is what produces lasting fitness: walk as your base, lift to preserve muscle and bone, sprint occasionally to keep your cardiovascular ceiling high, and play to keep your body adaptable and your brain engaged.

That’s not a novel prescription. It’s what humans did for most of our evolutionary history. We just stopped doing it when gyms started selling us the idea that one type of hard cardio was enough.

A few things from Walk worth implementing immediately: your walking speed matters, so don’t shuffle. Your foot health matters, so ditch the cushioned stability shoes and let your feet actually feel the ground. And the 10,000 steps target is more marketing than medicine, quality of movement beats raw step count.

One more thing: if you want to go deeper on any of this, the walking research, Zone 2, rucking, the Slowfit Movement pillar, Coach Keir AI knows the full methodology. The Slowfit Method® app is now live on the App Store, free to download with a 10-message trial. Ask it anything. It won’t shuffle. Want to learn more? Wrote about the new app here and here. I’m proud of it; sure hope you’ll check it out.

DOWNLOAD ON THE APP STORE

Your action today: go for a walk that is at least 30 minutes, outside, somewhere that isn’t a parking lot. Leave the earbuds out for the first ten minutes. Notice what happens to how you feel about yourself.

That’s the whole protocol.

—

See you out there somewhere!

-Keir

P.S. Speaking of walking, did a fair amount of that up the infamous Baker Beach Sand Ladder this past weekend during the 2026 Escape from Alcatraz Triathlon. Congrats, too, to Foghorn athlete (and eldest son) Max Beadling on his first triathlon (and on absolutely smoking his dad).

P.P.S. New website, new merch! Please have a look at the latest & greatest Foghorn website and if you’re interested in a new Foghorn hat (blue on black logo pictured above), let me know!