Athlete For Life
Can You Lower Your Biological Age?
by Jeremy Hudson, Athlete For Life
We’ve always trained with one assumption: fitness slows aging. Slowing the decline was the best we could hope for — it doesn’t reverse it.
And honestly, why would we think otherwise? There hadn’t been a single published study showing biological age could move backward.
Even Steve Horvath — the scientist who invented the ‘epigenetic clock’ used to measure biological age — didn’t expect it could run backward.
Then, in 2019, a small trial produced results that forced the question.
Horvath ran the analysis himself. He’d expected, at best, to see the clock slow down. Instead, it ran backward. His word for it: “futuristic.”
Since then, the evidence has been stacking up fast. And for anyone who used to be an athlete — anyone who remembers what it felt like to move well — this research should change how you think about your next few decades.
First — what is biological age?
Your chronological age is your birthday. Your biological age is how old your body actually is at the cellular level — and the two can be very different.
The most established way to measure it looks at your epigenetics: chemical tags that sit on top of your DNA and switch genes on and off. As we age, the pattern of those tags changes in a predictable way.
Researchers built algorithms — “epigenetic clocks” — that read the pattern from a blood or saliva sample and estimate your body’s true age. And it’s a better predictor than your birthday: a clock like this can forecast your health — and how long you’ll live.
And of course, everyone assumed this clock works just like the calendar one. Your chronological age only runs one direction — your birthday never moves backward — so why would your biological age be any different?
The evidence
And that assumption is exactly why you don’t believe you can get your body back. Somewhere along the way you concluded that the stiffness, the lost spring, the slowing down — that’s just what aging is.
And why wouldn’t you? There was no evidence to suggest otherwise.
Until now.
Here’s what changed.
Drugs (2019). The TRIIM trial gave nine middle-aged men a cocktail of growth hormone and two diabetes medications for a year. Biological age dropped by about 2.5 years. It was small and preliminary — but it was the first crack in the “one direction only” assumption, and it surprised the researchers themselves.
Diet and lifestyle (2021). Dr. Kara Fitzgerald’s team published the first randomized controlled trial in the journal Aging. Forty-three healthy men, ages 50–72. Eight weeks of a diet, sleep, exercise, and stress-management program. No drugs.
The results, in plain terms: the treatment group finished the program about two years biologically younger than when they started. The control group, who changed nothing, drifted about a year older on the clock.
Put the two groups side by side and the gap was 3.23 years after just eight weeks — and that difference was statistically significant. That’s the real headline: the difference between doing something and doing nothing.
Training (2020s). In a separate trial, women in midlife who had been sedentary took up eight weeks of combined aerobic and strength training — and their epigenetic clocks read two years younger afterward.
A 2025 research review in Aging pulled together the studies on exercise and biological aging and concluded that structured training can shift the body toward a younger molecular profile — and that structured training outperforms casual activity.
Any former athlete already knows the difference: there’s activity, and then there’s training. One fills time. The other has a purpose.
Muscle tissue itself. A meta-analysis of over 3,000 human muscle samples found that people with higher measured aerobic fitness carry younger molecular profiles in their muscle, and that training shifts those profiles toward a younger state.
But the same study showed the reverse is also true: by not training, you accelerate the aging process of your muscles. Your body responds to inactivity the same way it responds to training: it adapts. Just in the wrong direction.
Your body is always adapting — that never switches off. Training pushes your biological age down and not training pushes it up. So if you competed for years and then stopped, you didn’t hit pause. You changed direction.
But there’s something in that list you shouldn’t miss. The drug trial and the lifestyle trials landed in roughly the same place — around two to three years of reversal. A pharmaceutical cocktail got matched by four behaviors: how the participants trained, ate, slept, and managed stress. Three drugs, likely with side effects, versus four simple habits — and the habits held their own.
There’s an entire industry betting you’ll pay for the drug version when the behavior version is free.
So what actually moved the clock?
Every successful intervention above was built from the same short list. No exotic protocols. No thousand-dollar supplements.
The studies keep pointing at:
Training — and the dose is smaller than you think. A 2022 meta-analysis found resistance training cut the risk of dying from any cause by 15%, with the biggest benefit at around just 60 minutes per week. Follow-up research put the sweet spot at 60–120 minutes weekly.
Combine that with regular aerobic work and one large analysis found mortality risk dropped by 45%. Two to three structured sessions a week, with progression built in — remember, structured training outperforms casual activity.
That’s the evidence-based dose — and only about 5% of adults are getting it.
Whole foods, mostly plants. When Fitzgerald’s team dug into which part of their program did the heavy lifting, it was foods that were polyphenol-dense — the deeply colored plants: leafy greens, berries, herbs, and the like. Real food, not extracts.
Sleep. The successful protocols treated sleep as a pillar, not an afterthought. Research links short sleep and poor sleep quality to faster-running clocks.
Stress management. Chronic stress shows up on the clocks too — largely because it drives the behaviors that age us: worse sleep, worse food, less movement.
Now read that list again. Train consistently, with intent. Eat to fuel and recover. Sleep because that’s when the body adapts. Manage stress so recovery actually happens.
That’s not a longevity protocol. That’s just how an athlete lives.
When you were competing, nobody had to sell you on any of this. You trained with a purpose. You ate to perform. You protected your sleep before a big game. Recovery wasn’t a wellness trend — it was part of the job.
The researchers studying biological age essentially rediscovered the athlete’s lifestyle and measured what it does to the clock.
That’s the whole idea behind being an Athlete for Life. It’s not about reliving your glory days. It’s a mindset — treating your body the way you did when performance mattered, because it still does. The sport changed. The stakes got higher. What you’re training for now is the next thirty years.
The honest caveat
These are early studies — small groups, short durations. And numbers like two years or 3.23 years are group averages: some participants moved a lot, some barely at all.
But here’s what held up: as a group, the people who took action got younger on the clock, and the group that did nothing drifted the other way. Your exact number will be your own — everyone’s is — but which way you’re likely to move isn’t a coin flip. It follows what you do.
One more thing worth noticing: every one of those studies ran on lab testing — blood samples, algorithms, epigenetic clocks. But reading through what actually moved the clock, you probably already have a sense of what you need to work on. You don’t need a lab for that.
But the question this article asked was: can you lower your biological age? And the honest answer, based on the current evidence, is yes — and the best part is that the things that lower it are things you control.
Eight weeks. Now imagine a decade.
Here’s the thought I can’t shake. The Fitzgerald study created a 3.23-year gap between the group that acted and the group that didn’t — in only eight weeks.
So what’s the gap after a year of living like an athlete again? After five years? After a decade?
Nobody has run that study yet. But the two lines are moving in opposite directions — and if eight weeks can create a three-year gap, I can’t help imagining what’s possible in a decade of living this way.
If you want to know where you stand right now, take the Athletic Edge Scorecard. It’s a brief self-assessment — your own perception, so it’s a starting point rather than a verdict. But it starts the process.
Because before you can rewind it, you have to measure it.
Stay athletic,
Jeremy
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Jeremy Hudson is a strength and conditioning coach (NSCA-CSCS) with 27 years in the field. He runs Athlete for Life in London, training adults in their 30s through 60s to move like athletes again. Curious how you’re actually holding up? Find your Athletic Age in three minutes: athleteforlife.ca
