I have become less interested in the question of how long a person can live.
A more practical question bothers me now: what will those extra years look like?
There is a large difference between reaching old age and reaching it with enough strength to climb stairs, carry groceries, remember appointments and get out of a chair without assistance. Medicine has become quite good at keeping people alive. The harder problem is preserving the body that has to live through those additional years.
Exercise sits right in the middle of that problem.
For years, we have been told that exercise “slows aging.” The phrase appears everywhere. It is attractive, but it can also mislead. Exercise does not freeze the biological clock. It does something more measurable and perhaps more valuable: it can reduce the risk of several diseases associated with aging and help preserve physical function. It is also associated with a lower risk of premature death.
The real story, then, is not eternal youth. It is healthspan.
Living Longer Is Not Quite the Same as Aging Better
I think this distinction gets lost whenever we discuss longevity.
Lifespan is simply how long we live. Healthspan refers more broadly to the years we spend in reasonably good health and functional independence. Exercise matters because its effects appear across many of the systems that determine whether later life remains active or becomes progressively restricted.
The evidence on mortality is substantial.
A major dose-response meta-analysis published in the British Journal of Sports Medicine examined 196 articles covering 94 prospective cohorts and more than 30 million participants. Researchers found that higher levels of non-occupational physical activity were associated with lower risks of all-cause mortality, cardiovascular disease and several cancers. Read the study.
One finding deserves more attention than it usually receives. People did not have to become athletes to benefit.
The relationship was nonlinear, which means some of the largest relative gains occurred when people moved from very little activity to modest amounts. The researchers estimated that appreciable population-level benefits could occur even at activity levels below the full recommended amount.
That changes the conversation. For a sedentary 60-year-old, the relevant question may not be whether he can run five kilometres. It may be whether he can start walking regularly and keep doing it.
Muscle May Be One of Our Most Important Retirement Assets
When people talk about aging, they usually notice grey hair and wrinkles first. Muscle is quieter.
We can lose muscle strength and physical capacity with age, and the consequences eventually appear in ordinary movements: getting out of a low chair, lifting something from the floor or recovering balance after a stumble.
This is why resistance training deserves a much larger place in discussions about healthy aging.
A 2025 systematic review and meta-analysis of randomized controlled trials involving older adults with sarcopenia found that resistance training improved measures of strength and physical performance. The effects on muscle-mass measurements were less consistent, an important correction to the popular idea that resistance exercise matters only because it makes muscles larger. See the PubMed record.
Function matters. A stronger older person may find it easier to rise from a chair, walk confidently and perform ordinary household tasks. Those abilities rarely appear in glamorous anti-aging advertisements, but they are central to independence.
The World Health Organization’s guidance reflects this. Older adults should combine aerobic activity and muscle strengthening with multicomponent activity that emphasizes functional balance and strength.
Aging well is not simply a cardiovascular project. It is also a strength and balance project.
The Heart Responds Too
The cardiovascular benefits are easier to measure.
Exercise training can lower resting blood pressure. A large network meta-analysis of 270 randomized controlled trials involving 15,827 participants found reductions in systolic and diastolic blood pressure across several forms of exercise, including aerobic and dynamic resistance training. See the analysis.
The exact response varies between people. Exercise does not replace prescribed treatment for hypertension or cardiovascular disease. But movement is not merely a tool for burning calories.
The CDC’s physical-activity guidance states that regular physical activity lowers the risk of heart disease, stroke and type 2 diabetes. For older adults, activity also supports bone health and physical function while reducing fall risk.
This is where the old obsession with body weight can distract us. A person can become fitter without producing a dramatic transformation on the bathroom scale. Exercise can still improve cardiovascular fitness, strength and metabolic health. The scale tells only part of the story.
What Happens to the Brain?
This part requires more caution.
It is common to read that exercise “grows new brain cells.” The claim comes partly from compelling experimental research, particularly animal studies, but directly demonstrating exercise-induced neurogenesis in living humans is much harder.
We do not need that claim to make a strong case for exercise.
A major 2025 umbrella review and meta-meta-analysis published in the British Journal of Sports Medicine examined 133 systematic reviews covering 2,724 randomized controlled trials and more than 258,000 participants. It found that exercise improved general cognition, memory and executive function across the populations studied. Read the review.
Interestingly, the review did not conclude that harder exercise was necessarily better for cognition. Benefits were also found with light and moderate-intensity interventions.
So I would avoid promising that a daily walk will manufacture new neurons. There is already enough evidence to say something useful: regular movement supports brain health.
Can Exercise Really Make You Biologically Younger?
Now we reach the most intriguing part of the story.
Scientists increasingly distinguish chronological age from various measures of biological aging. Chronological age is simple. If you were born 65 years ago, you are 65.
Biological aging is harder to define. Researchers have developed biomarkers intended to capture aspects of the aging process. Among them are DNA-methylation or “epigenetic” clocks, which examine chemical modifications associated with patterns of aging.
A 2026 systematic review and meta-analysis published in The Lancet Healthy Longevity examined research on physical activity and biological age measured using DNA-methylation clocks. It found evidence linking physical activity with more favourable results on some measures of epigenetic aging. Read the review.
Exciting? Certainly. Proof that exercise makes you biologically younger? Not yet.
Different epigenetic clocks do not measure precisely the same thing. Much of the evidence in this field is observational, which creates another problem: people who exercise regularly may differ from inactive people in diet, smoking, income, underlying health and other characteristics.
Researchers try to adjust for such factors, but statistical adjustment cannot eliminate every source of confounding. Science has not established a reliable conversion in which a certain amount of exercise makes someone a specific number of years “younger.”
What we can say is more restrained and more interesting: physical activity may influence some biological processes associated with aging, and researchers are beginning to detect those relationships with molecular tools. The biological clock story is still being written.
You Do Not Need HIIT to Earn the Benefits
The fitness industry sometimes makes exercise unnecessarily intimidating.
HIIT has benefits. Running has benefits. Hard resistance training can have benefits. None of them is a compulsory entrance fee to healthy aging.
The WHO physical-activity guidelines recommend that adults accumulate 150 to 300 minutes of moderate-intensity aerobic activity each week, or 75 to 150 minutes of vigorous activity, or an equivalent combination. Adults should also perform muscle-strengthening activities involving the major muscle groups on at least two days each week.
For people aged 65 and above, WHO adds multicomponent activity emphasizing functional balance and strength on three or more days a week.
But targets should not become excuses.
Someone doing almost no exercise should not look at “300 minutes” and decide that anything less is pointless. The CDC makes the principle explicit: adults who sit less and perform any amount of moderate-to-vigorous physical activity gain some health benefits.
Start somewhere. Ten minutes can become twenty. A short walk can become a routine. Resistance training can begin with manageable movements rather than a gym full of intimidating equipment.
Consistency changes the equation.
Aging Well Requires More Than Cardio
If I were rewriting the usual anti-aging exercise formula, I would stop looking for one perfect workout.
Walking or another aerobic activity develops cardiorespiratory fitness. Resistance exercise protects strength and function. Balance work becomes increasingly important because a fall in later life can have consequences far beyond the initial injury.
The combination matters more than the fashionable label attached to a particular workout.
Older adults with medical conditions may need additional care. Someone with cardiovascular disease, significant mobility limitations, concerning symptoms or a long period of inactivity should discuss substantial increases in exercise intensity with an appropriate healthcare professional.
For most people, however, ordinary movement should not be treated as a dangerous medical procedure. Physical activity belongs in ordinary life.
The Anti-Aging Industry Sells the Wrong Dream
I understand why the phrase “reverse aging” attracts attention.
We can see aging in a mirror. We cannot see improved insulin sensitivity or better cardiorespiratory fitness so easily. Nobody wakes up excited because his gait speed has improved.
Yet those quieter changes may determine what old age actually feels like.
Can I walk through an airport without becoming exhausted?
Can I climb a flight of stairs? Can I carry my own shopping? If I lose my balance, do I have enough strength and coordination to recover?
These questions are less glamorous than asking for one’s “biological age.” They are also more useful.
Exercise cannot promise immortality. It cannot guarantee freedom from dementia, heart disease or disability. Genetics, disease, environment and chance do not disappear because someone takes a daily walk.
But the evidence now gives us something much firmer than the promise of eternal youth.
Regular physical activity is associated with a lower risk of premature death and major chronic diseases. Exercise training can improve cardiovascular health and cognition. Resistance training can help preserve strength and physical function as we grow older.
Perhaps we have been asking the wrong question.
The goal is not to make a 65-year-old body pretend that it is 35.
The more useful goal is to help that 65-year-old body keep walking, thinking and functioning for as long as possible.
That is not reversing age. It is aging better.