Introduction
I'm 75 years old and I just started strength training several months ago. I’m not one that likes photos of myself. I should document my progress.
I should have done this decades earlier. I knew that then and I know that now. I can’t say why I couldn’t pull the trigger to begin. Some character flaw. Maybe it was realizing there are many areas of life where I haven’t completed my assignment on earth. To complete my assignment I need to get and stay healthy. Too many things to do. I write about that in the family section.
When I look at the research on sarcopenia—the age-related muscle loss that predicts falls, fractures, and loss of independence—the data is unambiguous. Strength training matters. It might be the single most important physical intervention for healthy aging.
But here I am with light dumbbells in my living room, doing bodyweight exercises and working through some knee-strengthening protocols, trying to figure out the smartest way to build strength when you're starting late and can't afford to waste time on the wrong approach.
The question that's been keeping me up at night: what KIND of strength training should I be doing?
Because the mainstream advice—"build as much muscle mass as possible to prevent sarcopenia"—runs headlong into something that disturbs me as a physician. The same cellular pathway that builds muscle, mTOR, is the exact pathway that rapamycin shuts down. And rapamycin is the most proven longevity drug we have. It extends lifespan in every organism tested.
So which is it? Do I want to maximize muscle growth, or maximize lifespan? The research suggests I might not be able to do both.
I started digging into this paradox, and what I found changed how I'm thinking about my own training protocol. It turns out there's a third option nobody talks about: you can build the strength and power you actually need for longevity without chronically activating the aging pathways that come with chasing muscle size.
The distinction matters more than I realized.
The Consensus Nobody Questions
The medical establishment has a clear position on resistance training for older adults. The CDC, WHO, and American College of Sports Medicine all say essentially the same thing: adults need muscle-strengthening activities on two or more days per week, working all major muscle groups.
The guidelines typically recommend 8 to 12 repetitions per exercise. That's the classic hypertrophy range—the rep scheme designed to maximize muscle size. The reasoning is straightforward: we lose muscle mass as we age (sarcopenia), muscle loss predicts frailty and mortality, therefore we need to build and maintain as much muscle as possible.
This makes intuitive sense. Muscle is our metabolic sink for glucose and lipids. More muscle means better insulin sensitivity. Muscle provides the physical capacity to recover from a stumble, to carry groceries, to get up from the floor. The "muscle as longevity organ" hypothesis has genuine support in the research.
A 2019 study in Scientific Reports found that among nonagenarians and centenarians—people in their 90s and 100s—low muscle mass predicted mortality in women. The frailest didn't survive. The ones with preserved muscle tissue lived longer.
The fear driving the guidelines is legitimate. Falls are deadly in older adults. Hip fractures carry a 20 to 30 percent mortality rate within a year for people over 75. If you don't have the strength to catch yourself, you're at serious risk.
So the consensus says: lift weights, build muscle, prevent sarcopenia. The more muscle mass you can maintain, the better your chances of staying independent and alive.
I understand this reasoning. I accepted it without question for most of my career.
Then I started looking at the other side of the equation.
The Trade-Off Nobody Discusses
After 40 years in medicine and years immersed in longevity research, one thing keeps bothering me—the mechanism that builds muscle is the same one that speeds up aging.
The pathway is called mTOR—mechanistic target of rapamycin. When you eat protein, when you lift weights, when you stimulate muscle growth, you're activating mTOR. This is how your cells know to build new tissue. mTOR tells cells to grow, to divide, to synthesize proteins.
That's wonderful when you're 15 and growing six inches in a year. It's more complicated when you're 75.
Rapamycin is a drug that inhibits mTOR. It was discovered in soil samples from Easter Island in the 1970s. Initially used to prevent organ rejection in transplant patients, researchers eventually tested it in aging studies. The results were remarkable. In mice, rapamycin extends lifespan by 9 to 26 percent depending on dose and timing. It works in yeast, worms, flies, and mammals. It's the closest thing we have to a validated anti-aging drug.
The mechanism is clear: rapamycin slows aging by shutting down the growth signal.
This creates a paradox. The fitness industry tells you to activate mTOR through protein and volume training. The longevity science tells you to inhibit mTOR to slow aging. Both can't be right.
A researcher named Mikhail Blagosklonny calls this the "hyperfunction theory" of aging. His argument: aging isn't wear and tear. It's runaway growth signaling. Cells that should stop dividing keep getting told to grow. This creates senescent "zombie" cells that secrete inflammatory molecules and drive age-related disease. When mTOR stays chronically elevated, you age faster.
There's even a natural experiment that supports this. A population in Ecuador called Laron dwarfs has a genetic mutation that makes them completely insensitive to growth hormone. They're short—about four feet tall—but they show near-complete protection from cancer and diabetes. Only one non-lethal cancer case has been documented in this population versus 17 percent cancer rates in their relatives. The trade-off between growth and longevity appears to be real.
So what's someone starting strength training at 75 supposed to do? I need the functional capacity that comes from strength. But I don't want to accelerate my biological clock by constantly activating the aging pathway.
This is where the research gets interesting.
What Actually Predicts Survival
I assumed the question was simple: more muscle mass equals better outcomes. But when I looked at the mortality data more carefully, a different pattern emerged.
It's not muscle mass that predicts who survives. It's not even strength, defined as how much force you can generate. It's something called relative muscle power.
A 2025 study published in Mayo Clinic Proceedings by Araújo and colleagues analyzed this question directly. The researchers followed adults over time and measured three things: muscle mass, muscle strength, and muscle power. Power is force multiplied by velocity—how quickly you can move a weight or your own body.
The findings: relative muscle power was the strongest predictor of mortality. Not mass. Not strength. Power.
What does "relative power" mean practically? It's the ability to move your own bodyweight quickly. Sit-to-stand velocity. How fast you can get up from a chair. How quickly you can step up onto a curb. Whether you can catch yourself when you trip.
This makes biological sense. The muscle fibers that produce power are the fast-twitch fibers, and these are the first to die with age. By age 70, you might have lost 25 to 35 percent of your fast-twitch fiber size, with more dramatic losses approaching 50 percent by the 80s and 90s. The slow-twitch endurance fibers stick around longer.
When someone falls and can't catch themselves, it's not because they lack muscle size. It's because they lack the explosive power to react quickly. The neural pathways that fire fast have degraded. The fast-twitch fibers have atrophied.
Another term researchers use is "dynapenia"—loss of strength and power independent of muscle mass. You can have reasonable muscle mass and still be weak. You can have low mass but high strength-to-weight ratio and be functionally capable.
A 2023 study put it bluntly: strength matters more than size. And power—the ability to generate force quickly—matters most of all.
This shifts the entire training question. Maybe I don't need to maximize muscle mass. Maybe I need to maximize power output relative to my bodyweight.
The Training Paradigm Shift
Understanding how to stimulate muscle adaptation without chronic mTOR activation requires looking at the different ways muscle responds to training stress.
Researchers have identified three primary mechanisms that drive muscle growth: mechanical tension (the primary driver), metabolic stress (a secondary contributor), and muscle damage. While these mechanisms interact and ultimately converge on similar growth outcomes, the key insight is that high mechanical tension—heavy loads or explosive movements—can drive adaptation without requiring the high-volume metabolic stress that keeps mTOR chronically elevated.
This distinction matters enormously. If I can build the strength and functional capacity I need through mechanical tension rather than metabolic stress, I might be able to preserve muscle function without paying the full mTOR cost.
There's even evidence that rapamycin and muscle growth aren't mutually exclusive if you time things correctly. Studies show that intermittent rapamycin dosing can inhibit the aging pathways without blocking the acute muscle adaptation to training. The drug prevents chronic mTOR hyperactivation while still allowing the pulsatile signaling that supports tissue maintenance.
I'm not suggesting everyone take rapamycin. I'm pointing out that the "you must choose between muscle and longevity" dichotomy might be false. You can choose between different types of training stimulus, and that choice has metabolic consequences.
What I'm Implementing Now
I'm not an experienced lifter. I'm a 75-year-old doctor who's been doing light dumbbell work and bodyweight exercises for a few months. I've been following some principles from the knees-over-toes training approach—focused on joint health and movement quality—because I can't afford injuries at this age.
But after reviewing this research, I'm shifting my focus. The question I'm asking isn't "how do I build muscle mass?" It's "how do I build power and preserve fast-twitch fibers while minimizing chronic mTOR activation?"
That changes everything about how I'm structuring my training.
1. Intensity over volume I'm not doing multiple sets to failure (not that I ever was). I'm not chasing the muscle burn or the pump. Instead, I'm focusing on moving whatever weight I'm using with maximal intent. If I'm doing a bodyweight squat, I'm thinking about exploding up from the bottom. If I'm using dumbbells, I'm lifting with speed and control. The goal isn't to accumulate fatigue. It's to send a mechanical signal.
2. Fewer sets, more recovery Right now I'm training maybe 2 to 3 times per week. I'm not grinding through hour-long sessions. I do 2 to 3 exercises focusing on fundamental movement patterns—squat, hinge, push, pull—and I'm done in 30 to 40 minutes. The research on power training in older adults shows that low volume, high intensity produces better strength gains and functional outcomes than high volume moderate intensity. You don't need to beat yourself up.
3. Prioritizing power movements (safely) This is the trickiest part at 75. "Lift explosively" sounds great in theory. In practice, explosive movements carry injury risk if your tendons and connective tissue aren't prepared. I'm starting conservatively. Medicine ball chest passes while seated. Step-ups where I focus on driving through the front leg quickly. Resistance band work where I can move fast without heavy loading. If I progress to kettlebell swings or jump training, it will be gradual and carefully monitored. The principle is velocity against resistance. Move something with intent to accelerate it. That's the signal that preserves fast-twitch capacity.
4. Tracking different outcomes I'm not measuring my bicep circumference. I'm tracking functional metrics that predict independence: How quickly can I stand from a chair without using my hands? Can I get up from the floor without assistance? How fast can I climb a flight of stairs? These are the movements that correlate with power and fast-twitch function. These are what the mortality studies show matter.
The Practical Boundaries
I need to be honest about the limitations here. I'm exploring an approach that contradicts mainstream guidelines, and there are legitimate concerns.
First, the safety issue. Explosive training in older adults carries real injury risk. You need adequate warm-up, progressive overload, and probably some coaching to learn proper technique. Telling a 75-year-old to "move the weight fast" without context could lead to tendon tears or joint damage.
I'm progressing slowly. I'm prioritizing movement quality over load. If something hurts beyond normal training discomfort, I back off. This isn't about ego or hitting numbers. It's about sustainable practice.
Second, the lower bound matters. You need sufficient muscle mass. The research on power training shows it preserves strength without requiring maximum hypertrophy, but that doesn't mean you can get away with minimal tissue. There's a threshold below which you're too frail to function.
The sweet spot appears to be: enough muscle mass to support daily activities and provide metabolic buffering, achieved through mechanical tension and power work rather than chronic volume accumulation. Not bodybuilder size. Not wasting-away frailty. Functional sufficiency.
Third, I'm not claiming this is proven. The research connecting training approaches to longevity outcomes is observational, not experimental. We don't have 10-year randomized controlled trials comparing "power-focused training" to "hypertrophy-focused training" in older adults.
I'm making an educated bet based on mechanism and correlational evidence. I could be wrong. That's why I'm tracking outcomes carefully and staying open to adjusting.
The Bottom Line
The "more muscle mass, more health" narrative isn't wrong. It's incomplete.
Muscle mass provides metabolic benefit and physical capacity. But the training approach that maximizes mass—high volume, metabolic stress, chronic mTOR activation—might come with aging costs that nobody's accounting for.
The emerging picture suggests a different optimization target: relative power. The ability to generate force quickly. The preservation of fast-twitch fibers. The functional capacity to catch yourself when you stumble.
This can be achieved through mechanical tension—heavy loads or explosive movements—without requiring the chronic growth signaling that comes with volume-focused hypertrophy training.
I'm 75 years old and I'm just starting to learn how to train intelligently. I wish I'd understood this 30 years ago. But the research gives me a framework for making smart decisions now.
I'm not training to look like I lift. I'm training to move like someone who can still catch himself when he trips at 90. I'm training for power, not size. For function, not appearance. For the capacity to stay independent as long as my biology will allow.
There’s other considerations I will address in another article. VO2 max is considered to be the measure of your cardiovascular health. It has long been a metric for ability to avoid cardiovascular death. It is all of that. Endurance cardiovascular work improves that metric. There is confounding research which demonstrates that gymnasts and martial art practitioners actually live longer than the endurance athletes. The presumed mechanism is that they have adapted and trained for complex movements. They don’t run or bike in a straight line. It is presumed that they have that power and muscle training to catch themselves when falling
The approach: lift heavy when appropriate, move with intent to accelerate, keep volume low enough to recover fully, and prioritize the fast-twitch fibers that are most vulnerable to aging. Develop balance training aspects with workouts. Add HIIT training (also to be addressed in another article).
It's not about choosing between muscle and longevity. It's about choosing the type of muscle stimulus that supports function without chronically activating the pathways that accelerate aging.
I'm on that path now. Based on what I'm learning, I think it's a better path than the one the mainstream guidelines would have put me on.