So let’s say your calf is sore, do you have to avoid the gym for a month? Your knee flares up… should you stop walking and weight training? Can’t you hear how sad your biceps, chest, and back are? Again…The intuition is that rest is the safest option, and that any activity risks worsening things. I get it. But the harm from complete rest can be far more consequential. Let’s dive into this… It’s short. -ish.

.

Subscribe now

The Cost of Rest

Aerobic deconditioning begins within days of inactivity. VO2max can decline by 7 to 10 percent in just the first two to three weeks of detraining. Plasma volume drops early, within the first few days, which reduces stroke volume and cardiac output. And if you recall my heat acclimation post, you’ll remember that that is one of the key adaptations that needs to take place. The heart literally pumps less blood per beat than it did the week before.

After three to four weeks, the losses become more substantial. Capillary density in the muscles begins to decline. Mitochondrial enzyme activity decreases. The oxidative machinery that took months of consistent training to develop starts to dismantle itself, because the body does not maintain systems it is not using. From an evolutionary perspective, we did not have the resources to maintain tissue and physiology that wasn’t being utilized. Despite the amount of fuel we now have available… that evolutionary programming hasn’t changed.

Skeletal muscle follows a similar trajectory but on its own timeline. Measurable losses in muscle cross-sectional area can appear within two weeks of disuse. That’s why your leg is so skinny after it’s been in a cast for a month.

After a month, strength losses of 10 to 15 percent are common. In older adults, this rate accelerates because the anabolic signaling pathways that rebuild muscle are already less efficient. The muscle you lose at 55 comes back slower than the muscle you lost at 35, and that assumes you come back to training at all. When you lose the exercise habit… It’s hard to get it back.

Tendons are even less forgiving. Collagen turnover in tendons is slow under the best of circumstances, and prolonged unloading leads to structural changes that reduce stiffness and load tolerance. A tendon that has been rested for four to six weeks is not the same tendon you started with. It is less prepared to withstand the forces you will eventually ask it to withstand, which is one of the reasons that returning to activity after a prolonged layoff so often results in a new injury in a different location.

The Non-Physical Costs

Furthermore… Motivation can erode when routines dissolve. The identity of being someone who trains, who moves, and who shows up can quietly fade. Some of us can’t wait to get back at it. But far too many took years to get themselves into a gym... and a brief hiatus can crush that habit.

And we rarely just lose the month. Because the recovery from deconditioning is never linear. A month of inactivity can easily require four to six months to return to where you were from a physiological perspective. I’m not exaggerating. I’ve seen it in myself, and I see this in my office regularly. The injury itself healed in six weeks, but the deconditioning it caused took the rest of the year to resolve.

I am not saying that injuries don’t need respect. Some do require rest, modification, or temporary unloading of a specific structure. But resting one structure does not mean you have to rest the entire system.

I have a stress injury just above my tibial tubercle (knee) right now. It comes from compression of my patellar tendon against my tibia during deep-loaded flexion. So I cannot do deep-loaded flexion. But I can do a lot of everything else. Upper body work. Aerobic base training on the bike. Hip and core strengthening. Lateral and rotational work. If I had shut down entirely, I would have lost aerobic capacity, muscle mass, and the training consistency that keeps my system functioning and my mood stable. The rest would have cost me far more than the injury itself.

There’s Always Nuance…

Nuance. There’s always nuance. And this topic has a ton of it. Many patients want me to tell them exactly what they can and cannot do during recovery. I understand that instinct. First, we need to consider the injured structure and its needs. When it comes to guiding you for your injury…. You will learn how your knee, shoulder, or ankle tolerates activity far better than I ever could. I can and do give you guidance on what is likely to bother it. But I am often wrong, because the body is strange and humbling like that. What I expect to hurt sometimes doesn’t. What I expect to be fine sometimes isn’t. So I’ll ask them to test things. Try an activity, if it doesn’t hurt too much, continue. If it does, back off and try again in a few weeks. That process of testing and learning is a critical part of recovery.

Share

Pain after an injury is not always a stop sign; sometimes it is just a chill signal. The distinction between pain that signals harm and pain that signals discomfort is one of the most important things an injured person can learn, and it is something your doctor or physical therapist can help you interpret. These are some of the most important questions to ask the professionals you are entrusting to care for you.

• Do I need to rest completely?

• How long?

• Is there a risk of harm if I continue? Can you quantify it?

• When can I… Walk, run, lift with my legs, arms, back, etc.

• Can I start PT now?

Recovery from injury should never be all-or-nothing. There is a wide range of nuance between complete rest and full activity, and that middle ground is where most people should live with the typical injuries we see.

A patient with an ankle sprain shouldn’t leave with crutches and a boot and have a follow-up in 4 weeks. The downsides will be dramatic and unwarranted. Yes, we can protect the area for a short while, but get them into PT as soon as possible. Or have them back in 10-14 days to re-evaluate and see if progression would be tolerated. Another two weeks doesn’t sound like a lot… but to your heart and musculoskeletal system? It is.

Ask your doctors what your injury can handle. Ask whether pain is a warning to stop or a signal to slow down. Ask what you can do, not just what you can’t.

Refer a friend

Leave a comment

It’s not due solely to aging. They are the result of undertraining, detraining, or training with the wrong goals. For me, the real purpose of training is to preserve optionality — the ability to keep doing the things that make life rich and meaningful. I want to be able to hike, carry, travel, play, recover, adapt, and remain independent for as long as possible. That is what training for life means to me.

I also believe that fitness is not one thing. It is a collection of physical capacities that serve us in different ways, and they do not all decline at the same rate.

• Aerobic fitness matters because it supports heart and metabolic health, as well as recovery.

• Strength matters because muscle is essential to longevity and independence.

• Power matters because it disappears faster than strength and is often what keeps you upright, agile, and resilient.

• Balance, mobility, lateral movement, and rotational control matter because life does not happen in straight lines or controlled environments.

Top 5 posts to start with

1. The Midlife Athlete’s Playbook
   This is where I would start. It is the clearest overview of how I think about training priorities in midlife: strength, aerobic capacity, power, recovery, and the Enough / Better / Optimal framework. The guide is free for Members. The guide can also be purchased here.

2. Training at 62: What I Do, Why I Do It, and What’s at Stake If I Don’t
   This is the practical version of my philosophy. I walk through how I actually train, why each piece matters, and how I think about training for life, not just for performance.

3. Training at 63: What The Past Year Taught Me
   This is the update a year later: what held up, what changed, and what aging really asks of us if we want to keep building capacity instead of surrendering it.

4. Weight Training Builds Strength. Aerobic Training Builds Your Heart. You Need Both
   I wrote this because too many people still think lifting is enough for cardiovascular health. It is not. Strength and aerobic work do different jobs, and both matter.

5. Why Power Training Protects Your Independence
   Power disappears earlier than most people realize, and it is central to catching yourself, climbing, reacting, and staying independent. This is one of the most important ideas in the pillar.

10 common questions people ask about fitness and training for life

1. Do I need strength training or cardio after 50?
   Preview: I would not choose one. Strength preserves muscle, bone, and function; aerobic training protects your heart, metabolism, and endurance. You need both because they solve different problems.
   Read: Weight Training Builds Strength. Aerobic Training Builds Your Heart. You Need Both

2. How do I improve VO₂ max as I get older?
   Preview: I start with aerobic base work, not heroics. Build more low-intensity volume than you think you need, then use intensity sparingly and deliberately.
   Read: Module 5: Building Your Aerobic Base
   Also: Why Your Easy Pace Feels So Hard

3. Is Zone 2 overrated?
   Preview: The internet has turned Zone 2 into a slogan. My view is more practical: easy aerobic work matters a lot, but most people do not need to obsess over precise labels to get healthier.
   Read: Zone 2 Training… Why So Many Influencers Get It Wrong
   Also: The Myth of Zone 2: Why Zone 1 (and Even Zone 0) Might Be Better for Most of Us

4. Can I still build muscle and strength after 50 or 60?
   Preview: Yes. I reject the idea that age alone explains most decline. Muscle and strength are still trainable if you provide a meaningful progressive signal and recover well enough to adapt.
   Read: Module 4 – Strength for Longevity: How Much Is Enough?
   Also: Training at 63: What The Past Year Taught Me

5. How much exercise is actually enough for health and longevity?
   Preview: I like to remove the perfection trap. You do not need an elite program to earn major benefits. Going from nothing to something changes everything.
   Read: Enough, Better, and Optimal: How to Think About An Exercise Framework When Fear Is the Barrier
   Also: Less Is More (And The Data Finally Agrees)

6. Why does my easy pace feel too hard when I start aerobic training?
   Preview: Because most people start too fast. Easy training only works when it is actually easy enough to build the system you are trying to build.
   Read: Why Your Easy Pace Feels So Hard

7. Why should I care about power training if I’m not an athlete?
   Preview: Because life still demands speed. Catching a stumble, stepping up quickly, changing direction, and reacting under load are power tasks, not just strength tasks.
   Read: Why Power Training Protects Your Independence
   Also: Saturday Action Plan – Week 4: Power

8. Is balance trainable, or do we just lose it with age?
   Preview: Balance is trainable. What many people call “bad balance” is often a loss of neuromuscular control, coordination, proprioception, and power — all of which can improve with the right work.
   Read: Neuromuscular Control: The Skill We Start Losing Earlier Than Strength
   Also: Why We Fall—and Why It Matters More Than You Think

9. What should I do if I’m coming back after injury, surgery, or illness?
   Preview: I would not chase my old numbers right away. Return is a rebuilding phase. Aerobic base, connective tissue tolerance, nervous system readiness, and strength all come back on different timelines.
   Read: Coming Back After Injury, Surgery, or Illness Without Breaking Yourself a Second Time

10. How important is recovery in a good training plan?
    Preview: Recovery is not a luxury add-on. It is the phase where adaptation happens. If you under-recover, even a smart plan can turn into breakdown.
    Read: Recovery Is a Superpower — Module 7
    Also: 5 Things I Changed to Recover Better

Next Steps: The Midlife Athlete’s Playbook

If you want the full framework for how I think about training in midlife — including strength, aerobic health, power, recovery, programming, and how to adapt all of it to real life — start here: The Midlife Athlete’s Playbook. It is the best place to understand how I train, how I think, and how to build a body that keeps saying yes to life.

Stay strong,
Howard Luks, MD

They understand that strength matters, that an aerobic base is foundational, that intensity must be used carefully, and that recovery determines whether any of it actually leads to adaptation. The challenge is no longer knowledge. It is execution. This is a key variable. Executing on a well-conceived plan is where training can go off the rails. We still need to be able to read the signals… and we need to understand that what works for a few weeks might still lead to overtraining if we’re not staying vigilant. Let’s get into this…

This transition is where many people can begin to struggle. Not because they lack discipline… they made it this far. They’re disciplined. But the way they structure their training can create more stress than their system can consistently resolve. On paper, their week looks productive. In practice, it is not repeatable, and over time, that becomes the problem. As we have discussed, aging biology often dictates a larger recovery burden.

A training week only works if it can be repeated. We never want today’s workout to destroy tomorrow’s. That may sound obvious, but it is one of the most overlooked principles in how people approach exercise. It is easy to construct a demanding week. It is much harder to construct one that allows the system to return to baseline and be ready to do it again, not just once, but week after week without interruption.

When I look at a training week, I am not asking whether it is challenging. I am asking whether it is sustainable in the context of the person’s life and their current capacity. Can the system absorb the applied stress, resolve it, and return ready for the next exposure? If that cycle cannot be maintained, then the structure is flawed, regardless of how well-intentioned it may be. I run into this myself all the time. Especially at my age. I routinely need to dial back the effort or volume of a plan I roughed out 3 months ago. As midlife or master’s athletes, we’re rarely going to come across a plan that is repeatable week after week without some adjustment along the way.

Read more

This Module series is a step-by-step framework for building a system or body that performs well, progresses, and holds up over time. Each module covers one essential variable — tissue capacity, strength, aerobic fitness, intensity, recovery, load management, and progression — and explains not only what it is but also why it matters and how it interacts with the other variables. The series is written so that each module builds on the one before it, giving you a framework and the logic for thinking about training that goes far beyond individual exercises or workouts.

Whether you are starting from zero after years on the sideline or you just finished your second triathlon and want to keep improving without breaking down, the principles are the same. What changes is where you enter and how aggressively you load each variable. The modules give you the reasoning to make those decisions for yourself, rather than following a generic program that knows nothing about your life, your history, or your goals.

Subscribe now

This is not a series of specific training programs, but it is the logic behind every good one. If you understand how these variables connect and how to manage them across a week, a month, and a year, you will train smarter, recover better, and stay in the game far longer than people who just chase the next workout.

All the modules written so far are outlined below. They are meant to be read in order, since each variable is just as important as the one that precedes it or follows it.

1. Module 1: You Are Not Fragile: Fragility is not the default state of the human body. It is an acquired state. This module challenges one of the most damaging ideas in modern health: that your body needs to be protected from stress rather than prepared for it. We explore how beliefs about pain, aging, and injury shape behavior long before training begins, and why the absence of stress is not neutral. It is a biological signal to decline... or “narrow”.

2. Module 2: Why Impact Matters: Impact is not a dangerous force to be avoided. It is a biological signal that tells bones how dense to be, tendons how stiff to become, and the nervous system how to stabilize and coordinate motion under load. This module reframes impact as a spectrum, from stepping off a curb to changing direction quickly, and explains why removing it entirely is a problem. The risks of avoiding impact depend on the capacity of the system receiving the force.

Share

3. Module 3: Tendon and Tissue Capacity Most injuries do not happen because something suddenly breaks. They occur because your soft-tissue margins have quietly eroded. This module explains how tendons and connective tissues build or lose tolerance in response to the demands placed on them. Tendons are not fragile like glass. They manage the load and respond to the load they often see. Most tendon pain is not a sign of structural tearing. It is a sign of a mismatch between demand and capacity, and rest alone will not fix it.

4. Module 4: Strength for Longevity — How Much Is Enough? Strength in the context of longevity is not about performance ceilings. It is about margin: the delta between what your body is capable of and what life demands of it. This module walks through the dose-response relationship for resistance training, why the majority of health benefits occur at modest volumes, and why “enough” is actually enough. It is a strategy and explains why two to three modest sessions per week, maintained over years, outperform sporadic periods of high-intensity training followed by long injury-related or over-training-related layoffs.

5. Module 5: Building Your Aerobic Base: Your aerobic base is not built at the edge of challenge and difficulty. It is built well below it. This module explains why training below your first lactate threshold (easy pace) improves mitochondrial density, fat oxidation, and metabolic flexibility, thereby compounding the benefits over decades. Without a base, intensity becomes expensive. With a base, intensity becomes a tool. Aerobic base is your foundation, serving as the starting point for layering intensity. It determines how long you can tolerate life’s demands without systemic strain.

6. Module 6: Intensity and Locomotion: Intensity has a certain appeal. It feels productive and athletic. It also creates problems when it is introduced before the system is prepared for it. This module explains why the cardiovascular system adapts quickly to increased intensity, but connective tissue does not, and why most people need far less intensity than they think. We also discuss how locomotion exposes capacity gaps that can lead to injury. Intensity is not something to avoid. It is something to earn.

7. Module 7: Recovery Is a Superpower: There is a moment many people encounter where the same workout they have done for years no longer resolves the way it used to. That’s not due to a loss of fitness. It is a change in our recovery capacity. The biology of aging is real… and we can’t avoid it. This module covers how adaptation occurs during the recovery phase, and not during the session itself. It also explains why our recovery burden increases with age and how to read the signals your system provides. Recovery should not be an afterthought. It is the variable that makes consistency possible.

Refer a friend

8. Module 8: Load — Building a Week That Works: A training week only works if it can be repeated. This module shifts from understanding individual variables to assembling them into a sustainable structure. It covers why different types of training impose different physiologic costs, how to distribute stress across a week so each session sets up the next one, why life stress belongs in the same conversation as training stress, and how to respond when the system tells you something needs to change.

But… the stressors in your daily life don’t work that way. You step off a curb at an angle. You shuffle sideways to make room on a crowded sidewalk. You reach across your body to open a car door. You pivot in the kitchen, a heavy pot of water in hand. Every one of these movements is a test of rotational or lateral capacity, the strength and stability of the muscles that let you move confidently in the directions your life actually demands. And it’s not just strength… It’s power too. The ability to move laterally quickly and forcefully. Having this ability could save your life one day.

What Gets Stronger and Weaker

When you train only in the sagittal plane, you leave specific structures largely untrained. The gluteus medius is the muscle on the side of your hip, and it’s your primary stabilizer when you stand on one leg or shift weight laterally. Yes, some sagittal plane movements train it… But it trains it only in the sagittal plane. Squats or RDLs, for example

Every step you take is a brief single-leg stance that requires strong glutes. The gluteus medius keeps your pelvis level during that phase. A squat doesn’t load it that way. Neither does a deadlift. A person who deadlifts 400 pounds but has never trained laterally is strong in the gym but might be fragile in the world.

The lateral ankle stabilizers, particularly the peroneals on the outside of your lower leg, are responsible for keeping your ankle from rolling inward when the ground is uneven. That’s the capacity you need on an icy lot or when you misstep off a curb. But sagittal plane training mostly ignores them.

The trunk rotators and lateral flexors, the obliques, and the muscles deeper down your side control your body’s position when you rotate, lean, or shift laterally. These are involved in almost every real-world movement you do that isn’t a straight line, and they are minimally trained by the standard gym exercises that dominate most programs.

The connection to falls is there because life doesn’t stress you in the sagittal plane alone. A bump on the sidewalk, a misstep off a curb, a dog pulling on a leash. These are lateral perturbations, and each requires a fast and confident lateral corrective step. That corrective step requires the hip abductors (glutes) to fire quickly, the ankle stabilizers to engage instantly, and the trunk to shift laterally over a new base of support.

Falling is a major contributor to our morbidity and mortality…. Much larger than you might think. Start your fall prevention strategies now.

If any of those structures are too weak or too slow, the corrective action might fail. Falls to the side are a major cause of hip fractures, particularly in older adults. Building lateral stability is building hip fracture resilience.

Your Saturday Session

This session takes 20-30 minutes for the Enough and Better tiers. Do it once a week, or twice if you want faster progress. At the Optimal tier, expect 30-40 minutes, including rest. These sessions are built to scale. Start where you are, progress when you’re ready.

This Action Plan is for informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified healthcare provider before beginning any new exercise program, especially if you have any underlying medical conditions, injuries, or concerns. Participation is voluntary and at your own risk. If you feel unstable during these movements, have a partner nearby or a professional instruct you.

Exercise is the risk you take to avoid the complications of being still.

Lateral Band Walks

Place a resistance band around your legs just above your knees. Stand in a shallow squat position, feet hip-width apart. Step sideways, leading with one foot, and follow with the other. Keep the band taut throughout. You should feel tension in your outer hip. Walk 10 to 15 steps in each direction. That’s one set.

Enough: Light band, shallow squat, 2 sets. Use a band with tension you can feel, but not so much that the movement becomes difficult.

Better: Light band, deeper squat position, 3 sets of 10 steps each direction.

Optimal: Heavier band, deeper squat, 3 sets of 15 steps each direction.

This exercise trains the gluteus medius through the exact pattern it needs to function.

Lateral Lunges

From standing, step directly to the side with one foot. Bend the stepping knee while keeping the other leg straight. Feel your weight shift onto the stepping foot. Push off with the leg you step with, back to the center, and repeat on the other side.

Enough: Bodyweight, 2 sets of 8 per side. The higher rep count helps you learn the movement confidently.

Better: Hold a dumbbell or kettlebell at your chest (15-20 lbs), 3 sets of 8 reps per side.

Optimal: Heavier load (20 to 30 lbs), 3 sets of 10 per side, or add a 3-second pause at the bottom.

The lateral lunge trains hip abduction, hip adduction, and the lateral weight shift through a range of motion most people haven’t used in years.

Side Shuffles

Stand in an athletic stance, knees slightly bent, ready to move. Shuffle sideways for 10 to 15 yards, then shuffle back. Keep your feet from crossing. Stay low, controlled, moving with intent. This is the movement pattern you need in the crowded grocery aisle, on the playground with the grandchildren, in the moment when a lateral corrective step prevents a fall.

Enough: Shuffle 10 yards in each direction, moving slowly.

Better: Shuffle 15 yards in each direction, picked up to a moderate pace.

Optimal: Shuffle 20 yards in each direction, moving with speed, power, and control.

Read more

Rob is fifty-two and played basketball in high school. He kept playing pickup into his late twenties, then stopped, like many people do when work, kids, and the rest of life crowd it out.

Twenty-five years later, his 14-year-old son asked him to come shoot around in their driveway. Less than five minutes in, he had to sit down on the curb with his hands on his knees, breathing like he had run a fast mile. He sat there, looking at his son, and felt something he had not felt in years: the gap between the abilities he used to have and those he had now.

Subscribe now

Ann is forty-eight. She did not play organized sports as a kid, but she was active in other ways. She kept up with her friends on weekend hikes through her thirties; she could carry her own groceries and chase her kids around the yard without thinking about it. A few months ago, she went on a trip out west with a group of friends. The trip involved more hiking than she had done in fifteen years. The second day was hard. By the third day, she couldn’t go on, so she stayed back at the cabin while the others went up the trail. She told everyone she just needed a quiet day. She spent the day on the porch, but she did not feel quiet. She felt sidelined, and as she sat on that porch, she decided that something needed to change.

This guide is for both of them, and any of you who see your own life narrowing or are worried about your health fading.

Who This Is For, And Who It Isn’t

This is a guide for the reader who has been thinking about (re)starting, maybe for months or years, and has not yet found a starting point that feels right for them.

The fitness conversation online is loud, confusing, and crowded.

Most of what’s written online is not aimed at this audience either. Most of it is aimed at people who already train, who want to optimize, who already have a routine, and want a better one. The reader this guide is written for is somewhere upstream of all of that.

If you are that reader, I want you to know that this guide is not about suffering or challenge. It is not a twelve-week kick your ass program with before-and-after photographs of someone halfway through their journey. It is not a workout per se. It is the platform that comes before all of that, the foundation that makes everything else possible, and building the foundation is not as hard as you think it is.

The hard part is starting. Let’s do this…

Why So Much Starting-Over Content Misses The Point

The cultural conversation around starting a fitness program is structured in a way that is unhelpful for most of you.

The dominant narrative is the dramatic transformation. Before-and-after photographs. Couch to marathon in twelve months. These stories are almost always told from the other side of the gap. Implicitly, the message is that the way back is intense, performative, and visibly difficult, and that those who succeed are those who summon the willpower to endure long enough.

Share

Many look at me and ask how I can comment on what it means to start from zero. Well… I may be in the best shape of my life now, but it wasn’t always like this. My residency found me working 100+ hour weeks. Then, as a sports surgeon by day and trauma surgeon at night, while helping raise 3 children… well, it was hard to find time to exercise. I managed a few walks or runs… but nothing like what I used to do. Eventually, I found time and trained back. But then came a long post-viral syndrome, and then an unplanned surgery. Each time, I had to start from zero. This is my lane.

The first step from sedentary to any movement produces the largest single biological return in the entire fitness journey. The biggest benefits to your health occur on the left side of this curve. I’ll dive into this in detail in a bit.

The people who succeed in the long run are almost never the ones who summoned willpower for a six-week challenging sprint. I’ve seen many people grind out and train for a 5k. Only to stop training after they run it. The people who succeed are those who started with something so small they could not fail at it, and they let their successes accumulate.

I have spent thirty years watching patients (re)start. The ones who get there are not the ones who suffered the most at the beginning. They are the ones who started with something they could actually do, on a random Tuesday afternoon, with no special equipment, and who came back and did it again on Thursday.

A Brief Word On The Narrowing

I have written elsewhere about what I call the narrowing. It is the slow, quiet shrinking of a person’s physical capacity that happens across a decade or two. It happens slowly, so it’s mostly invisible, until it’s not. You stop carrying the heaviest groceries, then you stop carrying any. You stop taking the stairs, then you stop attempting them. You stop the activities you used to do without thinking, and the stopping happens so gradually that you do not notice it. You normalize these changes, and you attribute the changes to age, to busyness, to a hundred reasonable accommodations, and at some point you find yourself, like Rob, on a curb after five minutes of activity, or like Ann, on a cabin porch while your friends are on the trail.

I am not going to fully develop the narrowing narrative here. What I want you to understand is that the narrowing is real, and it is often reversible across a much wider range than you think.

Refer a friend

You Need Much Less Than You Think

This is the single most important section in the guide.

The biology of the first step from sedentary to any movement is not linear. It is curved, and the curve is steepest right at the beginning. The first ten minutes of walking per day produce more cardiovascular benefit than the next thirty. The first five repetitions of a basic strength movement produce more neural response than the next twenty will. The first session of any kind of movement, in a body that has been sedentary for years, produces measurable adaptations within the same week.

This matters because it inverts the assumption most starting-from-zero readers carry into the work. The assumption is that meaningful progress requires meaningful effort, and that the effort needed is far beyond where they currently are.

A ten-minute walk three times a week will produce measurable improvements in resting heart rate, blood pressure, and aerobic capacity within four to six weeks in a previously sedentary adult. Five wall push-ups twice a day will produce measurable improvements in upper-body strength within the same window. Standing on one foot while you brush your teeth will produce measurable improvements in balance within weeks. None of these is impressive, but they all count. More than you think.

The implication for you is simple. The first thing you do this week will be the most valuable single thing you have ever done for your body. Not because it will be impressive on paper, but because the slope of the response curve is steepest at the very beginning, and this is where you are at.

You Cannot Fail At This If You Start Small Enough

The other thing I want you to understand before we get to the specific actions is that the people who (re)start successfully are almost always the people who chose a first action they could not fail at.

The first action has to be small enough that on the worst day you can imagine, in the busiest week, with the worst sleep, you can still do it. If your plan for Monday is a forty-five-minute run, you have a plan that will fail on the first hard week, and the failure will compound into a story you tell yourself about how you cannot do this. If your plan for Monday is a ten-minute walk, the worst day produces a five-minute walk, and the five-minute walk is still a success, and then those successes accumulate.

That is the whole game, in many ways, and everything else is downstream of it. Once you start, and once you start to build a habit, progression comes far more naturally for most of you.

Read more

Heat can be a very serious problem… We’ll get into that after we cover the process of heat acclimatization.

.

Every year, I see patients and fellow athletes go through this same cycle. All of us are frustrated by it, some are confused, and a few are concerned. They had a great spring, felt strong, and were hitting their numbers. Then the temperatures climb into the 80s, and suddenly everything comes off the rails. Many know it’s the heat, some misinterpret the signals… but most underestimate the time it takes to adapt. Some will continue to push despite the elevated effort and heart rate, some will head inside to a treadmill, and others will run before sunrise to avoid the heat altogether. Most also do not know the most common signs of heat illness. Being prepared to recognize it might save a life one day.

Encountering a physiological challenge that their body hasn’t adapted to yet isn’t easy— as a matter of fact, it’s humbling… but your body is remarkably good at adapting to heat… if you give it the chance. You simply can’t fight your physiology until it’s ready. And it only gets worse as we age. Let’s get into how to acclimatize to the heat.

Why Heat Is a Big Deal for Exercise… a bit of science.

When you exercise, your working muscles generate a lot of heat. At rest, your metabolic rate is fairly low, and heat dissipation isn’t a challenge. But during moderate to vigorous exercise, your body can produce 5 times as much heat as at rest. That heat has to go somewhere, and your body has only a limited number of ways to get rid of it: radiation, convection, and, most importantly, the evaporation of sweat from your skin.

When the air temperature is cool, the gradient between your skin and the environment is large enough that you can radiate and convect a lot of heat away passively. But when the ambient temperature approaches your skin temperature (around 91-93°F), those passive mechanisms become much less effective. You become almost entirely dependent on evaporative cooling, which is sweating. And when humidity is high, sweating becomes much less efficient because the sweat can’t evaporate as readily.

This also creates competition for blood flow within your body as it tries to rid itself of excess heat. Your working muscles need a lot of blood to deliver oxygen and fuel. Unlike in cooler months, your skin now needs blood to carry heat from the core to the surface for cooling. Your gut always needs blood to maintain function, and your brain is always hungry. At this stage of the acclimation process, there’s not enough blood to serve all of these purposes well.

Your heart has a finite cardiac output to distribute. In the heat, the cardiovascular and nervous systems are forced to make compromises. The nervous system, specifically the autonomic nervous system, helps modulate blood flow to various areas. Your blood vessels can constrict to nothing or expand dramatically. That’s how the body can shut down or increase blood flow to a region. All winter, the vessels in your skin have been constricted. Your body isn’t going to send a lot of blood to the skin if it’s cold out. That would cool your core temperature, and the body protects that at all costs. But now that it’s warm out, the body again needs to protect your core temperature from rising, so it dilates the vessels in your skin.

The problem is, your muscles need the same flow received all winter… but your vascular system doesn’t have enough blood to share. So it decreases muscle blood flow a bit, allowing it to shunt blood to the skin to dissipate heat. This is only one mechanism; we will discuss others in a minute, but….This is where the trouble starts.

What Actually Happens When Your Body Acclimates to Heat

Your body’s response to repeated heat exposure is one of the most robust and well-characterized adaptations in exercise physiology. Stay with me for a second because the physiology is worth understanding.

Over the course of about 10 to 14 days of regular heat exposure (exercising in the heat for 60 to 90 minutes per session), a cascade of adaptations occurs:

For Members, I walk you through 4 critical physiological changes that occur in our body during the first two weeks of heat exposure. You’ll learn how your plasma volume expands by 10-12% in the first five days, why your sweat rate can nearly double with full acclimation, and why sodium losses drop at the same time. I will cover the warning signs of heat exhaustion and what to do immediately if you or a friend believes it is happening. Heat illness can escalate into a deadly situation in as little as 15 minutes… You need to know what to do.

We’ll also cover cardiac drift, and what to do when your heart rate climbs mid-ride at the same effort, and why the acclimation timeline shifts after forty-five. We’ll close with the hydration, timing, and safety rules that will carry you through the first few hot weeks of the season without losing fitness or self-respect. Finally, we’ll discuss an amino acid that may help you withstand the heat.

I love physiology, but want you to exercise safely in the heat…Let’s get into this…

Read more

Master’s athletes need to understand the biology of aging and how it will impact their training. We cannot train the same way at 60 as we did at 35. We can have the same goals and compete at the same events, but getting to the start line requires a different approach. The athletes who ignore that reality are the ones I end up treating. The ones who respect it are the ones who keep showing up to compete

.

The physiology of aging is real. I’m not going to pretend otherwise. After 50, anabolic resistance makes it harder to build muscle. Satellite cell populations decline. Power drops roughly twice as fast as strength. Bone density falls, particularly in women post-menopause. VO2max declines about 10 percent per decade without deliberate training. Recovery takes longer. Protein requirements go up, not down.

All of that is true. And none of it means you should stop competing or accept the trajectory most people are on.

The problem isn’t aging. The problem is not adjusting for it.

Most athletes respond to the first signs of slowing down by either ignoring them, trying to push harder, or backing off entirely. Their knee hurts, so they stop squatting. Their back is stiff, so they skip the deadlift. They feel tired after a hard training block, so they cut the volume across the board… or push harder to try and get their energy back. These approaches don’t scale well.

I get it. First, it’s hard to recognize the signals, and then it's hard to interpret them. Training as we age can be messy. Many give in to the instinct to protect themselves, which makes sense. But our physiology runs in the other direction. The less you do, the faster every one of those capacities declines.

It’s possible to train despite the aging physiology we’re fighting.

The answer is rarely to train less. It’s to train differently. Smarter programming, better recovery management, and a clear understanding of which capacities decline fastest, how to address each one, and which new exercises to consider adding to your workouts.

How physical stressors actually occur

Before I get into the specifics, I want to explain why this guide is structured the way it is, because it’s different from most training advice you’ll find for master’s athletes.

Think about the moments that actually injure people. A slip on a wet trail where your foot goes sideways, and your body has to catch itself laterally. A twist during a transition or a sudden direction change. A stumble off a curb where you need to decelerate and redirect in a fraction of a second.

None of these happens in a straight line. None of them is slow. And none of them look anything like a controlled set of bicep curls or steady-state work on a trainer.

The physical demands of competition and daily life are multiplanar, unpredictable, and fast. They involve lateral force, rotational force, rapid deceleration, reactive balance, and the ability to produce power quickly enough to prevent a catastrophic outcome. A hip fracture after a fall in someone over 65 carries a 20 to 30 percent one-year mortality rate. Roughly half of survivors never walk independently again. The fall itself takes less than a second. The question is whether your body will have the capacity to respond in that fraction of a second.

It is not okay to be able to squat 300 pounds if you cannot broad jump two feet. Strength without power, without lateral quickness, without rotational capacity, and without reactive balance is incomplete. And this is where injuries live.

That is what shapes my approach. And it is why this guide covers what it covers.

What most training programs miss

Walk into any gym and watch the masters athletes. Most of them are doing sport-specific work and maybe some general strength training. Both are valuable. But most programs miss the capacities that actually determine whether you stay injury-resistant and competitive into your 60s, 70s, and beyond.

Most programs move in one plane of motion: forward. Life’s stressors, as well as competition doesn’t. You navigate uneven terrain. You absorb unexpected forces. You change direction under load. The physical stresses of real athletic activity almost always include a rotational or lateral component, and if your training never asks your body to produce or absorb force in those directions, you’re leaving the most common injury mechanisms completely unaddressed.

Most programs also ignore power as a distinct training variable. They train strength, which is how much force you can produce, but they never deliberately train how fast you can produce it. Power is what determines whether you catch yourself from a fall, whether you can accelerate out of a turn, and whether you can respond to a sudden shift in terrain. It declines roughly 3 to 3.5 percent per year in older adults, compared to 1.5 to 2 percent for strength. It’s the capacity that disappears fastest, and almost nobody over 50 is training it well enough to prevent that loss.

Most programs underestimate what bones actually need to stimulate growth. Walking is 1.2 times body weight. Cycling provides almost no axial load at all. The threshold for a bone-building stimulus is roughly 3 to 4 times body weight in ground reaction force. That means heavy resistance training, impact loading, and jumping variations. Not 10-pound dumbbells or a vibration plate.

What I’ve learned from three decades of treating active adults

I’ve operated on thousands of knees, shoulders, and hips. I’ve rehabbed patients back from fractures, surgeries, and illnesses. And I’ve trained my own body through my 50s and 60s with all the wear, recovery challenges, and adaptation slowdowns that come with the territory.

The athletes who do best long-term are not always the ones with the best genetics or the least arthritis on imaging. They’re the ones who kept loading intelligently. They maintained their muscle mass, power, balance, and aerobic base. When something went wrong, they had reserves to draw on. When they needed surgery, they recovered faster because they went in stronger. When they stumbled on a trail, they caught themselves rather than falling because they still had the lateral quickness and reactive power to correct.

The athletes who struggle are those who either didn’t adjust their approach or stopped entirely. Usually, for understandable reasons. A scan that scared them. A doctor who told them to “take it easy.” Pain that they interpreted as damage rather than as a signal to modify and reload. The stopping is almost always more harmful than the original problem.

I also learned something important from my own training. At 62, I use my bike differently than I did at 40. It’s no longer about performance on the bike. It’s about aerobic volume with a low recovery burden. The bike builds and maintains my aerobic base without the joint stress and tissue fatigue that running accumulates at higher mileage. That frees up recovery capacity for the things cycling can’t provide: heavy lifting, impact loading, rotational power work, and lateral agility drills. The bike isn’t the program. It’s the platform that makes the rest of the program sustainable.

The capacities that actually matter for master’s athletes

If I had to distill 30 years of clinical and personal experience into a list, these are the training priorities for any master’s athlete who wants to keep competing and stay on start lines:

Muscle mass and strength. Resistance training with progressive overload, hitting compound movements at loads heavy enough to challenge you within 6 to 12 reps.

Power. Resistance training with explosive intent on the concentric phase. Moving a submaximal load as fast as you can.

Balance, quickness, and multiplanar movement. Lateral hops, rotational medicine ball work, agility drills, and single-leg stance with perturbation.

Aerobic fitness. Low heart rate training most days for base building. One to two sessions per week of higher-intensity intervals to maintain VO2max.

Bone density. Heavy resistance training plus impact loading. 40 to 50 high-impact reps per session, 2 to 3 times per week. Drop landings, jumping variations, and the lateral agility work from above all count toward this total.

Recovery. Sleep, protein timing, structured deload weeks, and rest days between heavy sessions. After 50, recovery is no longer something you can ignore. It’s the window where every adaptation actually happens, and it takes longer than it used to.

Protein. 1.2 to 1.6 g/kg/day, distributed across 3 to 4 meals with 30 to 40 grams per meal to reach the leucine threshold. Breakfast is where most people fall short. Your muscle is less responsive to protein than it was at 35, so you need more to trigger the same synthetic response.

None of these is complicated on its own. The challenge is fitting them all into a sustainable weekly structure alongside your sport-specific training that you can maintain for years, not weeks.

The Midlife Athlete’s Playbook: What the download contains

I’ve put together a comprehensive PDF guide that takes everything in this post and goes much deeper.

What’s inside the guide:

The guide opens with something most training programs ignore.

From there, it covers each training priority in detail with specific protocols, evidence-based targets, and my Enough/Better/Optimal framework applied to every variable. That includes force threshold tables for bone loading, the LIFTMOR exercise protocol, rep and set prescriptions for power training, a complete section on rotational and lateral movement training with specific exercises and progressions, aerobic programming with low heart rate training and VO2max interval protocols (including short sprint alternatives with lower injury risk), recovery variables with minimum and target thresholds, protein dosing tables with leucine content by food source, and three complete sample training weeks at the Enough, Better, and Optimal levels.

It also includes a section on imaging that I think is particularly valuable: a table of common MRI findings, their prevalence in pain-free adults, and a decision framework for when those findings should change your training versus when they should not.

The back half of the guide is a complete exercise reference you can take to the gym. Every exercise is organized two ways: first by movement pattern (hip hinge, squat, push, pull, rotation, lateral, power, impact, carry) so you can find what fits your program, and then by muscle group (glutes, quads, hamstrings, chest, shoulders, upper back, core, hip abductors/adductors, calves) so you can target specific weaknesses. Each exercise includes a key coaching cue, scaling options, and a note on which part of the guide it connects to.

The guide is fully referenced and formatted as a professional PDF you can save, print, or keep on your phone at the gym.

Download The Midlife Training Guide

Read more

This is a solid post… many of you have asked me to write more about recovery. Here is my attempt to address many of your fantastic questions.

That change that you feel is not a loss of fitness. It’s certainly not a signal to push harder. More often, it reflects a shift in your ability to recover from the work you are doing. The system is no longer resolving stress as efficiently as it once did, and the cost of each session is beginning to accumulate in subtle ways that become increasingly apparent over time. This is one of the most critical things to understand as an aging athlete.

Most people respond to this moment in one of two ways. They either push harder, assuming that more effort will restore what feels like it is slipping, or they retreat, attributing the change to aging and accepting it as inevitable. Neither response addresses the underlying issue.

Recovery is not a passive process that occurs simply because you stopped training. It is a physiologic capacity that determines how effectively your body can absorb stress, resolve it, and return to a state where adaptation is possible. Like strength, aerobic fitness, and tissue tolerance, this capacity can be developed, maintained, or allowed to decline. But the most important thing you need to do is… respect it. These can be subtle warning signs; you must be able to recognize them.

ICYMI

If you’re new here, this series walks through what it takes to maintain and build capacity as we age. We began by reframing fragility and fear, discussed the importance of impact, then moved through tendon and tissue capacity, strength, and the development of an aerobic base. In Module 6, we discussed intensity and why it must be layered onto a prepared system rather than used as the foundation.

Once you begin to view recovery this way, it becomes clear that it is not separate from training. It is the outcome of how well the system you are building is able to manage the stress you impose on it. Every session creates a disturbance—mechanical, metabolic, and neurologic—and the purpose of that disturbance is adaptation. But adaptation only occurs if the system can resolve what has been imposed.

If it cannot, the stress does not disappear. It accumulates.

That accumulation is rarely dramatic at first. It shows up as a slightly higher resting heart rate, a slower pace, a little more stiffness in the morning, a subtle change in mood, or a reduced willingness to train. These are easy signals to ignore because they do not stop you from continuing. In fact, most people continue to train through them without hesitation, because nothing has clearly “failed.”

In my office, this is the pattern I see most often. Patients rarely describe a single session that caused their problem. Instead, they describe a period of time where training felt just a bit harder to recover from, where something never quite returned to baseline, and where small signals were dismissed because they did not seem important. By the time they present, the system has already been operating outside its ability to adapt.

The injury, when it finally appears, feels sudden, but the process that led to it was not.

Recovery sits at the center of this process because it determines whether the stress you apply leads to adaptation or to accumulation. That distinction becomes more important with age, not because you lose the ability to improve, but because the margin for error narrows. The same mistake that would have resolved easily at 30 may persist at 50, and at 60 it may become the beginning of a longer interruption.

Read more

I met Milan a few weeks ago at the climbing gym. A robust 50 year old gentlemen there for an advanced climbing class. The issue was that he had trouble walking. Both of his achilles were on fire. It turns out he was a professional basketball player in his country 30 years ago. And last week his friends invited him to play. He hadn’t played in over a decade.

The achilles tendons of a 50-year-old can play basketball. Mine can still play at 62. His issue was that his achilles were not trained for that load or intensity. He learned an important lesson… but it will take him a few months to fully recover.

Module 5 covered the rationale for building an aerobic base. Most people accept that aerobic health is important. Perhaps they know that cardiorespiratory fitness is a key variable for living longer. When people think about aerobic endurance training, they usually think about suffering. They picture hard intervals, breathlessness, burning legs, and sweat on the floor. They think about pushing. They assume aerobic fitness is built at the edge. That assumption is one of the most persistent training errors I see — especially in midlife athletes. And since most of us are training for life… and not an ultra, that module was relevant to all of us.

Welcome to module 6. Intensity has a certain appeal. It’s sexy. It feels productive. It feels athletic. It gives us the impression that something meaningful is happening. For many people, it is also the part of training they enjoy the most. Others, as I see in my office each week, loathe the thought of it.

Both reactions can create a problem.

Like Milan, most people reach for intensity before they have earned it. As I will explain in this module, intensity is not something to avoid, nor do I often do it. There is a goldilox zone. Very important adaptations occur in the intensity zone. Besides, how much intensity do we need? And for how long do we need it? I think you might be surprised… Let’s do this.

Read more

I have spent more than 25 years as an orthopedic surgeon watching what happens to people’s lives as they age. Not the dramatic events like fractures, surgery, or car accidents— but the quieter erosion we normalize so easily. The things people stop doing. The trips they can’t take. The grandchildren that they can’t keep up with. The hobbies that disappear, not because they chose to give them up, but because their bodies made the decision for them.

Background: The Narrowing

Most people’s lives narrow. Not all at once, instead… gradually, a little at a time, until the opportunities available to them are a fraction of what they once were. I’ve watched it happen to patients who were otherwise healthy, who thought they were doing fine, who didn’t realize the margin was shrinking until it was already gone.

Subscribe now

Long ago, I decided that mine wouldn’t.

That decision is the reason I train the way I do. Not to look a certain way and certainly not to compete or hit a particular number on my watch. I train for life. I train to keep my opportunities open — to hike, climb, play tennis, travel, and stay physically capable of doing the things that (for me) make a life worth living well into my seventies, eighties, and beyond. That’s the goal. Everything below is in service of that goal.

What follows is my typical training week, the reasoning behind each component, and how I think about the dose required to get the benefit. I’ll be direct about what the evidence supports and honest about what I find difficult. I pull it all together in the end with a weekly schedule. I’ll be honest… it’s a lot. In my enough, better and optimal framework, my week is squarely in the optimal range. You should not think that you need to do all of this. But my rationale for my approach might help you figure out what your week should look like.

To that end… I’ve included an Enough / Better / Optimal framework for each training domain so you can calibrate it to your own life. That’s important because biology doesn’t require you to do exactly what I do. It requires you to give it a meaningful signal. We're going to talk about the quality and quantity of that signal, and you’ll need to tailor it to your abilities and needs.

A downloadable weekly training guide with full workout details is available at the end of this article.

Training for Life, Not for a Goal

Most people, when they exercise, train what’s comfortable. They do the things they’re already decent at, in the planes of motion they’re familiar with, at intensities that feel manageable. That’s understandable, and It’s precisely why our functional capacity erodes. It’s okay to get comfortable being uncomfortable.

The body adapts to what you ask of it — and only to what you ask of it. If you never jump, you lose the neuromuscular wiring for jumping. If you never move laterally, your hip stabilizers weaken, and your balance in the frontal plane deteriorates. If you never train rotation, you lose the core strength and power to handle the rotational stressors that real life constantly delivers — the awkward lift, the sudden twist, shoveling snow, or trying to catch yourself from falling.

The body becomes very good at a narrower range of movements, and that narrowing mirrors the narrowing of life I’ve watched happen in my office for 25 years.

Training for life means deliberately resisting that narrowing. It means building and maintaining the full spectrum of physical capacity: aerobic base, strength, power, rotational core, lateral movement, balance, and landing mechanics. Not because any single component is the answer, but because they are all part of the same integrated system — and because aging degrades each of them through different mechanisms and at different rates. You cannot maintain one and ignore the others and expect the system to hold.

I also want to say something about myokines, because they also shape most everything I do. Skeletal muscle is the body’s largest endocrine organ. When you challenge it — aerobically and mechanically, with power and speed — it secretes signaling proteins that communicate with virtually every other organ system in the body. The training program I’m about to describe isn’t just about keeping your joints working and your balance intact. It is a continuously renewed pharmacological signal that reduces your risk of cardiovascular disease, metabolic disease, dementia, and cancer. That’s the molecular biology of what happens when you move. It’s also the basis for a book I’ve started to write.

Aerobic Base: The Daily Foundation

I run or ride six to seven days per week. Most mornings, before anything else happens, I am either on the road or on the bike. This is not negotiable for me, and it hasn’t been for years. The timing of these aerobic sessions are the one variable I fully control, and I protect it accordingly.

Here’s what a typical week looks like on the aerobic side. I run four to five miles three days per week at a conversational pace… low heart rate (~120-125 bpm), where I can speak in complete sentences without laboring. The other days I ride a stationary bike. During the week, those rides are typically an hour. Saturday is my long ride — two to three hours. Can’t ride for two hours? Can you sit on a couch and watch a movie for 2 hours? Well… do that on the bike. You don’t have to go hard.

Sunday is my longer run. For total-minute calculations, I also count hikes, walks with the dogs, and other active movement toward my aerobic minutes, because they should count—they are real cardiovascular and metabolic work.

Most weeks, I accumulate more than 600+ minutes of aerobic activity.

Thursday is my intensity day. I start with a three-mile easy run to warm up, then move into either hill repeats, sprints, or a fartlek — unstructured speed work where I push hard for varying durations based on how I feel. Occasionally, I’ll do an intensity session on the bike instead, but that’s the exception rather than the rule. Every other aerobic session stays at a conversational pace. One day of intensity. The rest is low-intensity volume.

That 600-minute target is not arbitrary. Arem et al. (JAMA Internal Medicine, 2015) found that exercising at three to five times the recommended public health minimum — roughly 450 to 750 minutes of moderate activity per week — was associated with a 39 percent lower all-cause mortality risk compared to inactive adults. The dose-response curve for aerobic activity doesn’t flatten the way most people assume. For the adaptations that matter most with aging — VO2 max preservation, mitochondrial density, sustained myokine secretion — more volume produces more benefit, and that relationship continues well beyond what public health guidelines recommend.

VO2 max is worth understanding because it’s a number I care about a lot. It’s your maximal oxygen uptake — the ceiling of your aerobic capacity — and it is among the strongest predictors of longevity in the medical literature. A landmark study by Mandsager et al. (JAMA Network Open, 2018) followed 122,000 patients for a median of 8.4 years and found that low cardiorespiratory fitness was associated with a higher mortality risk than smoking, diabetes, or end-stage renal disease.

You do not need a ton of intensity to raise your VO2max. My regimen keeps my VO2 max above 50… which is in the top 5% for my age. That’s enough. The intensity needed to boost it higher increases my injury risk and recovery burden. And consistency matters far more than intensity when training for life.

This is by far the longest and most comprehensive training guide that I have written. More science, lots of explanations, and as usual, a lot of videos.

The downloadable guide is available at the end for Members.

In addition, I have created a more in-depth Midlife Training Guide… Members can download that guide here. While Non-members can purchase the guide here.

Read more

Why I’m doing these modules

After decades in clinical practice and coaching many longevity clients, I’ve come to believe that many outcomes—good and bad—are determined long before training begins.

They’re shaped by beliefs about pain, aging, injury, and fragility. They’re shaped by fear on one end of the spectrum and excess on the other. I see this play out in patients who stop moving because they’re afraid to get hurt, and in people who train hard without restraint until something breaks.

Both paths limit long-term capacity.

These modules are meant to sit between those extremes. They’re not about telling people to do less or more. They’re about helping people make better decisions about stress, recovery, and progression over time.

ICMYI:

Module 4 was about strength… Most conversations about strength training begin in the wrong place. They begin with numbers. How much weight? How many sets? How many days per week? Somewhere along the way, strength became framed as a competitive endeavor rather than a biological need. It was always framed as something you chase, measure, and optimize, rather than something you build to protect yourself against loss.

Your aerobic base will not be built at the edge. It will be well below it. A lot less stress and stuggle than you think.

Aerobic base is your body’s ability to produce energy efficiently using oxygen. It reflects mitochondrial density, capillary networks, fat oxidation capacity, lactate clearance, and autonomic balance. It determines how much work you can do before stress accumulates. It is not how hard you can go. It is how long you can go without breaking rhythm.

Most people run too fast on their easy days and too slow on hard days. They live in the middle. The middle feels productive. It produces sweat and fatigue. It also produces a kind of chronic metabolic strain that builds tolerance more than efficiency.

When you train below your first lactate threshold, a conversational pace with slow, sustainable breathing, you are teaching your body to prefer oxygen over urgency. You expand mitochondrial volume. You improve fat oxidation. You lower the cost of movement. You reduce sympathetic activation at submaximal workloads. You make recovery easier, not harder.

Now… I am NOT saying that we don’t need intensity, too. We do. Intensity has a role. But we build things on top of a foundation or base. And unless you have a strong fat oxidation engine, and most of you do not, then this should be your priority. The ability to oxidize fat is not only important in endurance sports. The physiology of fat oxidation differs significantly from that of glycolysis, or burning glucose for energy. The body prefers to burn fat during low-intensity exercise. You have an infinite supply of it. It’s also less “costly”, is more efficient, and produces fewer free oxygen radicals.

There is a need for, as well as a place for intensity… just not too much of it.

Aerobic base is not glamorous training. It can be downright boring, and when you first start, it can be mentally painful. It does not produce dramatic numbers on social media. Some feel that if you’re not sweating and hurting, then nothing beneficial is occurring. That thinking is understandable, but wrong. Addressing our aerobic base physiology will lead to healthier adaptations that compound over decades.

A large aerobic base lowers the heart rate required for a given pace. It increases stroke volume (intensity increases this more). It improves endothelial function. It enhances parasympathetic tone. It shifts your inflammatory profile toward a more favorable state. It makes higher intensities more accessible when you choose to use them.

Note to Members: The Clinician Sidebar discussion is back… thank you for all the nudges to continue with this series. I’m glad the technical nature of these sidebar summaries resonates with many of you.

Read more

Why I’m doing these modules

After decades in clinical practice and coaching many longevity clients, I’ve come to believe that many outcomes—good and bad—are determined long before training begins.

They’re shaped by beliefs about pain, aging, injury, and fragility. They’re shaped by fear on one end of the spectrum and excess on the other. I see this play out in patients who stop moving because they’re afraid to get hurt, and in people who train hard without restraint until something breaks.

Both paths limit long-term capacity.

These modules are meant to sit between those extremes. They’re not about telling people to do less or more. They’re about helping people make better decisions about stress, recovery, and progression over time.

ICYMI:

Earlier this week, I posted about managing the decline associated with aging. We can’t hide from the fact that these changes occur, but we shouldn’t attribute all the loss we see and feel solely to aging. This post is relevant to this current module, and you may wish to read it first.

The pursuit of longevity requires a reframing of these questions themselves. When the goal is not winning, but continuing, thriving, and remaining independent, the primary question is no longer how strong you can become. It becomes how strong do you need to be to preserve capacity, independence, and resilience over decades?

This is an important module. This is one of the reasons why I have changed the way I frame my training posts into Enough, Better, and Optimal. All of you know that you should be doing something. But you hate the gym, hate the idea of sweat and discomfort… i’ve heard this from you in my office for decades. The Enough section will work for you. Then there are those like me who thrive on the discomfort. I’ve gotten comfortable being uncomfortable. That’s why the Optimal guidance exists.

But as we pursue longevity… we need to understand that we do not need to be in the Optimal range to benefit from 90% of the longevity/healthspan upside. Enough or Better is, well, enough. But how much is enough?

That is the question this module is meant to answer.

Strength, in the context of longevity, is not about aesthetics or performance ceilings. It is about the margin. Margin is the space between what your body is capable of and what life demands of it. When that space is wide, unexpected stressors are absorbed. When it narrows, ordinary events begin to feel threatening. Illness lingers longer. Minor injuries cascade. Recovery slows, and confidence erodes. Worse… falls exacerbate weakness due to forced rest periods. Your world begins to narrow as your ability to navigate various landscapes erodes.

Read more

This isn’t a workout of the week. It isn’t a challenge. And it isn’t something you “complete.”

It’s a growing reference library designed so you can return to it as your body changes, your training evolves, and your priorities shift over time. That’s also why it will eventually live outside the Substack ecosystem.

Module 3

Most people think injuries happen because something suddenly breaks. A tendon snaps. A meniscus tears. A disc herniates. A bone fractures. It seems like it should be abrupt and dramatic, as if one wrong step or careless movement caused a failure that couldn’t have been predicted.

In practice, true sudden failure is uncommon. The vast majority of people in my office with joint or tendon pain never had a substantial injury. What usually fails is not a structure, but a margin. Let me explain.

Long before a tissue ever reaches a breaking point, its tolerance has quietly eroded. Not from a single event, but from a prolonged mismatch between what that tissue is capable of and what it is being asked to do. As that margin narrows, ordinary life begins to feel risky. Movements that were once unremarkable start to provoke pain. Activities that once felt safe begin to feel threatening. When the margin becomes small enough, even routine forces can exceed a tendon’s structural capacity.

Subscribe now

This is not a story about fragility. It is a story about capacity.

Capacity is not something the body preserves automatically. It is something it builds or loses in response to the environment it experiences. From an evolutionary perspective, our bodies will not invest time, energy, or material in maintaining the structural integrity of tissues that don’t require it. This is the foundation of fragility… or durabilty… and it is one of the key reasons our tendons and tissues thrive, or degrade and degenerate over time.

Our first module focused on the concept of fragility. When someone believes their body is fragile, every movement becomes cautious, every sensation feels threatening, and every progression begins to seem risky. That belief alone can limit adaptation. It shapes behavior, narrows what feels possible, and quietly constrains what the body is ever allowed to become.

Our second module focused on impact. For many people, impact has become synonymous with danger. Jumping is risky. Running is harmful. Landing is something to avoid. Even the word itself—impact—carries a sense of threat. And so, as people age, they are often advised to remove it entirely from their lives, as if it were an optional feature rather than a foundational one. We discussed why impact matters and how our fear often derails our anti-fragile goals before we even get started.

We often talk about tissues as if they are passive, fixed structures waiting to be injured or protected. In reality, muscle, tendon, bone, cartilage, and the nervous system are highly complex living systems. They are constantly remodeling and adjusting their structure and behavior in response to the stresses they encounter. This is basic evolutionary biology.

Share

When tissues are exposed to appropriate mechanical stress, they become more tolerant of that stress. Collagen reorganizes. Stiffness changes and coordination improves. When that stress disappears, tolerance and margin fade. It’s often quiet and gradual, until it’s not. You do not feel collagen turnover slowing. You do not feel fiber alignment changing. You do not feel the nervous system becoming more threat-sensitive. Until one day, you do.

Read more

If Module 1 challenged the idea that the human body is inherently fragile, today’s module takes that idea one step further. It examines one of the most misunderstood, avoided, and biologically necessary forms of stress: impact.

ICYMI:

1. Our first Module

2. I was a guest on the Science of Maximal Athletic Development Podcast the other day. I joined both and . I was honored to be their guest. This was a great conversation about healthspan and longevity in the athletic development space. Enjoy.

The Science of Maximal Athletic Development

MSMRL 11: Dr. Howard Luks - Why We Should Train for Life!

Train for Life, Not Just Performance…

Listen now

3 months ago · 20 likes · 2 comments · Alan Couzens, Iñaki de la Parra, and Howard Luks MD

For many people, impact has become synonymous with danger. Jumping is risky. Running is harmful. Landing is something to avoid. Even the word itself—impact—carries a sense of threat. And so, as people age, they are often advised to remove it entirely from their lives, as if it were an optional feature rather than a foundational one.

But that framing is not neutral. It changes how people move, how they train, and what their tissues are ever asked to tolerate.

Impact is not just a mechanical event. It is truly a fundamentally necessary biological signal.

It tells bones how dense they need to be.
It tells tendons how stiff and elastic they must become.
It tells muscles how quickly they must generate force.
It tells the nervous system how to coordinate and stabilize under load.

When that signal disappears, those systems do not remain unchanged. They adapt downward.

Subscribe now

What impact really is

Impact is not simply “hard landings” or “dangerous forces.” It is any rapid exchange of force between the body and the ground or an external object. It occurs when you step off a curb, descend stairs, catch yourself from a stumble, or change direction quickly. These are not athletic acts. They are acts of daily living. And you require training to withstand and tolerate these forces.

What makes them feel dangerous is not the presence of impact itself, but the absence of preparation for it!!

In physics, force is a product of mass and acceleration. In biology, force becomes meaningful only in relation to the tissue’s capacity to tolerate it. A force that is trivial for one person may be injurious for another—not because the force is inherently dangerous, but because the system receiving it is underprepared.

This is the part that is often missed. And this is a source of fear for far too many.

Risk is not absolute. It is relative.

A low-capacity system experiences everyday forces as high-stress events. A higher-capacity system experiences the same forces as a routine one. The difference is not bravery. It is biology.

Why bones, tendons, and cartilage need impact

Bone is not static. It is a metabolically active tissue that responds to mechanical strain. When exposed to dynamic loading—particularly loading that includes rapid changes in force—bone increases its mineral density and improves its structural architecture. This is why impact has such a strong effect on skeletal health, particularly in relation to osteoporosis and fracture risk.

When that loading disappears, bone does not maintain its structure out of loyalty. It downregulates. It becomes lighter, less dense, and less able to withstand force.

Tendons behave similarly. They are not just passive ropes connecting muscle to bone. They are viscoelastic tissues designed to store and release energy. That property—elasticity—is built and maintained through dynamic loading. Without it, tendons become “stiffer”, less tolerant of rapid force, and more vulnerable to injury when those forces inevitably appear.

Cartilage, too, depends on movement and cyclical loading to maintain its health. It has no direct blood supply. Its nutrition comes from compression and decompression, which drive fluid exchange. Removing dynamic load does not protect cartilage. It deprives it.

These systems do not deteriorate because people age. They deteriorate because they are underused.

Age modifies the rate of adaptation, not its existence. Yes, we adapt more slowly.

Read more

These modules are designed to help people build fitness, resilience, and long-term capacity. Strength, aerobic health, impact, and intensity all matter, and we will cover them all. But decades of clinical experience have taught me that outcomes are often decided long before any formal training ever begins—by beliefs.

When someone believes their body is fragile, every movement becomes cautious, every sensation feels threatening, and every progression begins to seem risky. That belief alone can limit adaptation. It shapes behavior, narrows what feels possible, and quietly constrains what the body is ever allowed to become.

That is why this series begins here.

One of the most damaging ideas in modern health and fitness is not that people should train harder. It is that they should train less because their bodies are fragile. Knees are framed as delicate. Backs are portrayed as inherently vulnerable. Tendons are treated as if they are easily damaged by normal use. Aging bodies, in particular, are often described as if they require protection from stress rather than preparation for it.

This belief rarely comes from malice. It usually comes from fear—fear of injury, fear of pain, fear of making something worse. Because that fear often wears the language of caution and responsibility, it spreads easily. It sounds reasonable. It feels protective. And over time, it causes real harm.

I have spent decades watching what happens when people are taught to avoid movement instead of adapt to it, and the pattern is remarkably consistent. As people do less, they become capable of less. Physical capacity gradually erodes, confidence diminishes, and stresses that were once trivial begin to feel disproportionately threatening. Over time, even ordinary movements can start to feel risky. What often begins as an attempt to be careful slowly becomes a path toward genuine fragility.

This post exists to interrupt that process.

Below the post will be a Clinician’s Sidebar. I have a fair number of healthcare members. These sidebars will be brief, but more technical. Please let me know your thoughts on this format/program as we begin our 6-month module series today.

The core idea

Fragility is not the default state of the human body. It is an acquired state.

Humans did not evolve to be protected from stress. We evolved to survive it.

Read more

Most people think of a warm-up as something you do to “get loose.” That’s not really the point. The real goal is to wake up the systems that control movement, coordination, and energy delivery before you ask them to perform.

You’ve felt this before… Think about a single-leg RDL or a balance drill. Your first set is a mess. You wobble, or you don’t feel as strong as you should. But the second set is better. By the third set, things feel smooth and controlled. That change didn’t happen because your muscles got stronger in five minutes… It happened because your nervous system woke up.

A proper warm-up is a neuromuscular system warm-up. You’re reminding your brain where your joints are in space. You’re increasing the speed and accuracy of motor unit recruitment. That’s where nerves attach to your muscles.

You’re improving the timing between stabilizers and prime movers. When I’m hopping in different directions, I’m not “doing cardio.” I’m teaching my nervous system how to accept load, redirect force, and respond quickly… basically the same skills running, lifting, and cycling demand.

This matters even more for endurance athletes. Before a run or ride, your muscles don’t instantly shift into efficient energy production. Mitochondria ramp up. Enzymes involved in fat oxidation and aerobic metabolism increase their activity. Blood flow redistributes. Oxygen delivery improves. Some proteins involved in energy transport and contraction are upregulated on demand. That process takes time. A warm-up primes that machinery so you don’t feel flat, heavy, or awkward in the first miles.

Skipping this step doesn’t just make things feel harder — it increases injury risk. Cold systems react slowly. Poor timing and delayed force absorption are how small stumbles turn into strains, tendon pain, or falls. Warming up is how you buy yourself margin.

That’s why these hopping drills matter. They prepare the systems that coordinate balance, coordination, and power. They prepare our connective tissues for impact… tendons enjoy the warm-up. These drills basically tell your brain, “We’re about to move — pay attention.” Whether you’re running, lifting, or cycling, the principle is the same: don’t go from zero to demand.

I do these in the same order that I present them. This only takes a few minutes. I usually walk for 5 minutes first, then do these hopping drills and take off on my run, a ride, or a tough day in the gym.

Forward Hop: 50’

Backward Hop: 50’

Subscribe now

Side Hop: Right and Left. 50’ in both directions:

Slalom Hop: Forward and Back- 50’

High Knees: 50’

Share

Single Leg: Both Directions- 50’

Side Hops: Two Legged- 50’

There are a few other variations that I could show you. But these will suffice for a solid warm-up. Now go out there and try them.

-Howard

Leave a comment

Share

As we age, the body still adapts beautifully to hard training - but it punishes poor load management with interest. One extra session, one impatient jump in volume, and you’re sidelined for weeks. Sometimes months. This is one of the most common reasons that I see people in my office. Their training was going well… until they abruptly changed something. Now they have a lingering overuse injury.

Many tendon or joint pains in older athletes are training errors. Understanding this and preventing them can go a long way toward enabling you to train longer and build more fitness before an injury rears its head and knocks you back.

I’ve changed my own training to match this reality. I still run fast, but usually once a week instead of twice. I still climb, but twice a week instead of three. The last time I tried pushing back to three climbing sessions, I tore a forearm muscle and earned myself a long stretch of forced rest.

Subscribe now

That’s the tax on overuse as we get older: conditioning takes months, sometimes years. Losing that conditioning takes days or weeks.

The research supports exactly what the body tells us. We don’t lose the ability to reach high intensity. We lose the tolerance for how often we can touch that intensity or volume.

What Actually Changes With Age

Older muscles recover more slowly from resistance exercise due to delayed, prolonged, and less efficient recovery. Contributing factors include anabolic resistance, extracellular matrix stiffening, mitochondrial dysfunction, unresolved inflammation, and alterations in satellite cell function [1,2].

In studies following older adults for up to 240 hours after exercise, full recovery of muscle strength was still not observed. This lack of complete recovery was consistent across almost every variable measured [2].

This isn’t about losing fitness. It’s about the fact that our biology is now working on a different timeline.

The cellular mechanisms that drive adaptation - satellite cell activation, extracellular matrix remodeling, resolution of inflammation, mitochondrial biogenesis - all proceed more slowly. The adequacy of recovery is impaired in older age, with recovery being delayed or attenuated following an acute exercise challenge [1].

But adaptation still happens. It just requires more patience.

The Recovery Timeline: What the Research Shows

After a challenging strength workout targeting large muscle groups, older adults likely need 48-72 hours before training those same muscles hard again, compared to shorter recovery windows for younger adults [3,4]. Recovery in your 60s and beyond can extend to 4-7 days, depending on workout intensity [4].

For high-intensity interval training specifically, the numbers are even more striking. Many older adults require nearly 5 days of recovery between HIIT sessions [5]. Not three days. Not four. Five. I didn’t write the article… Don’t shoot the messenger.

Recovery time depends on the intensity, duration, and type of exercise. High-intensity lifts that force muscles to work to failure require more recovery time regardless of age, but older athletes may need even more time [6].

This explains why my once-a-week sprint session works, but twice-a-week doesn’t anymore. The adaptation window hasn’t closed. It’s just gotten longer.

Share

What About Eccentric Loading?

Exercise with significant eccentric loading increases recovery time in older athletes compared with exercise with minimal eccentric loading, in which no difference exists between young and old [7].

Eccentric contractions - when muscles lengthen under load, like lowering a weight or running downhill - cause more muscle damage and require longer recovery windows. This has implications for how we structure training.

Downhill running, plyometrics, heavy negatives in the weight room - these create disproportionate recovery demands as we age. They’re not off-limits. They just can’t be frequent.

Intensity Remains Trainable

Higher-intensity, longer-duration exercise was inversely associated with cardiac aging and physical frailty risk in older adults [8]. High-intensity exercise in older adults enhances muscle strength, bone density, cardiovascular fitness, metabolic health, and cognitive function [9]. That’s good news :-).

Intensity isn’t the enemy. Frequency without adequate recovery is.

In contrast to the perception of slower recovery, repeated days of intense endurance cycling were similarly tolerated by young and veteran athletes in terms of performance. However, there was a greater change in perception of muscle soreness, and significant changes in fatigue and recovery were observed in veteran athletes [7].

Older athletes can handle the intensity. They feel it more and need more time between sessions.

The Conditioning-Deconditioning Paradox

Age-related muscle loss (sarcopenia), reduced circulation, and reduced tissue repair capacity all contribute to slower recovery [4]. But muscle mass continues to decline with age, and deconditioning happens quickly.

This creates a cruel paradox: It takes us longer to build fitness, but we lose it just as fast - maybe faster - when we stop. A few weeks off due to injury set you back months from where you were. Then you’re older than when you started, so rebuilding takes even longer.

This is why protecting training time matters more than maximizing training volume. An injury-free year of moderate training beats a year of aggressive training interrupted by three months of rehab. Every single time.

The Margin for Error Shrinks

When you’re 25, you can make mistakes and bounce back. Train too hard for a week? You’re tired for a few days, then fine. Ramp up volume too fast? Maybe some soreness, but it resolves.

At 45, 55, 65? That same mistake costs you weeks. Sometimes months. The system is less forgiving of impatience, less tolerant of poor spacing between hard efforts.

Research shows that older muscles recover more slowly, with recovery times extending from 24-48 hours in young adults to 48-72 hours in middle-aged and 4-7 days in older adults [3,4].

The adaptation you’re chasing - the strength gains, the cardiovascular improvements, the power development - still happens. Your mitochondria still multiply. Your muscle fibers still remodel. Your cardiovascular system still expands capacity.

It just takes longer to consolidate. Push that timeline, and you’re not training anymore. You’re accumulating damage.

Share

What This Looks Like in Practice

I run hard once a week. Zone 5, all-out effort. The rest of my runs are easy - Zone 2, conversational pace. One hard session is enough. Maybe more than enough. The adaptation happens in the 6 days between those efforts.

I climb twice a week with at least two full days between sessions. My forearms, fingers, and connective tissues need that time. Trying to climb three times a week was sustainable in my 30s. It’s not anymore. I learned that the hard way.

I lift three times a week, but I rotate muscle groups and movement patterns. I don’t hit the same muscles hard more than once every 3-5 days. The timeline has shifted.

I track how I feel more than I track metrics. If a workout that should feel routine feels hard, I back off. That’s not a weakness. That’s recognizing my system needs more time.

The Variables That Matter Most

Intensity, duration, and type of workout all affect recovery time. Long-duration efforts place more stress on the body than short, moderate sessions. High-intensity workouts, especially if unfamiliar, require more recovery time because they represent unaccustomed exercise [6].

Volume matters. Intensity matters. But frequency - how often you return to high-stress training - matters most as you age.

You can still do hard things. You just can’t do them as often.

For Members: Below, I provide detailed information on load management. I will also teach you how to recognize the warning signs of breakdown. They’re not as easy to identify as you might think.

Furthermore, I break down the specific training guidelines that have worked for thousands of athletes I’ve treated over 25 years - recovery windows for strength training, HIIT, and endurance work at different ages, how to structure your training week to maximize adaptation while minimizing injury risk, the warning signs that tell you when frequency is too high before you end up sidelined, how to practice load management using both subjective feel (RPE) and objective data from wearables (HRV, resting heart rate, sleep tracking), and how to integrate these tools.

Hence, you catch problems before they become injuries. This is the practical framework for keeping your athletic life intact as you age - not by backing off, but by training smarter and adjusting before you break.

Read more

Interestingly, intensity drives so many healthy adaptations, yet the brain resists it at every turn. It’s an interesting paradox. Why would the brain fight against strain that produces such dramatic healthy adaptations?

When effort rises, breathing quickens, and muscles start to burn, the brain interprets those sensations as danger. From an evolutionary perspective, it’s a survival mechanism that conserves energy and prevents harm. That made sense when food was scarce and survival depended on avoiding unnecessary exertion.

But that same circuitry now works against us. The discomfort that triggers the urge to stop is also what drives the most meaningful biological change. I further believe that the intensity level that triggers the brain's reaction is lower, and the fear many have about injury, etc, is worsening.

Subscribe now

Intense effort releases hundreds of myokines—molecules that reduce inflammation, improve insulin sensitivity, strengthen blood vessels, and enhance brain function. It’s how the body signals growth, repair, and adaptation.

The brain evolved to keep you safe in the moment. The body evolved to adapt over time. Training teaches the two to cooperate. The more you expose yourself to controlled intensity, the more the brain learns that effort isn’t danger.

Many of the things we need to age well — strength, endurance, better health, and confidence — live on the other side of discomfort.

Not necessarily pain, not injury (the risks are lower than you think), just that familiar edge where things stop feeling easy. Your brain is not often your ally here…

Many people spend their lives avoiding discomfort. The signal is too strong and too easy to obey. As we age, most people fear it. I see them and hear from them every day in my office. They fear activity, harm, discomfort... but not the structural/biological consequences that avoiding this domain brings.

They stop when the breathing gets heavy, when the muscles start to burn, when the brain whispers “enough.” But that edge is where adaptation happens. That’s where the body learns, and the mind toughens.

The brain can be taught to accept intensity. To accept discomfort.

You don’t need to chase suffering, but you do need to try to stop avoiding effort. Growth isn’t built in comfort. It’s built in the small, repeated moments when you choose to stay and work more intensively than you’re used to.

That’s why this long post is about what happens when you get comfortable being uncomfortable.

If you’ve followed my writing for a while, you know I talk a lot about the science of how movement and effort promote healing, resilience, healthy aging, and more. This isn’t just about mental toughness. The physiology of intensity runs deep. When you push into effort and approach that edge, numerous beneficial changes occur. Some are psychological, most are physiological.

For Members, I’ll dive into what’s actually happening under the hood: how the body interprets intensity, the signals it releases, and why this cascade is more potent—and more targeted—than anything you can buy in a vial. This is the fundamental biology of effort, and understanding it just might change how you approach training.

Read more

Too many people view fitness as a short-term endeavor: getting fit for summer, losing weight for a wedding, or preparing for an event. But what if we flipped the script? What if you thought of your muscle mass, bone density, VO2 max, and aerobic capacity like a retirement account?

As we age, we experienc…

Read more