Somewhere around the two-hour mark, the benefit simply stops climbing. Spend 90 minutes to two hours a week lifting weights, doing press-ups, sinking into squats, and your risk of dying from any cause over the following decades drops by about 13 percent. Push past that, grind out a third or fourth hour, and the curve goes flat. The body, it seems, has heard enough.
That is the headline finding from one of the longest looks yet at resistance training and how long people live. Researchers tracked 147,374 people, most of them American nurses and health professionals, for up to 30 years, and watched what happened.
The benefits of aerobic exercise, the running and brisk walking and cycling that gets you puffed, have been nailed down for decades. Lifting weights has been murkier. We knew muscle-strengthening work was good for you in a general way, which is why the guidelines have long nudged us towards it at least twice a week, but the precise dose, how much actually buys you the most life, stayed fuzzy. Most earlier studies measured people’s habits just once, at the start, then waited to see who died. People change, though. A snapshot misses that.
So the team, led from the Harvard T.H. Chan School of Public Health, did something more painstaking. Every two years, they asked the same people the same questions about their exercise, then averaged it all out across the decades.
The numbers that emerged are oddly specific. At 90 to 119 minutes a week of strength work, the risk of dying from cardiovascular disease fell by 19 percent, and the risk of death from neurological disease, the dementias and their kin, by a striking 27 percent. Both reductions held even after the researchers stripped out the effect of aerobic exercise, smoking, diet and the rest. And then, above two hours, nothing more.
Cancer threw up the strangest pattern of the lot. There, the protection showed up only at the low end, a modest dollop of strength work, under an hour a week, and vanished at higher volumes.
Why a ceiling, and why such a low one? Nobody is entirely sure, and the researchers are careful not to overclaim. For the heart, the likeliest story involves arterial stiffness, the gradual hardening of the body’s plumbing that predicts cardiac trouble. A single hard lifting session can stiffen arteries briefly; sustained, regular training over years seems to do the opposite and loosen them, especially when paired with aerobic work, which is itself a known softener of arteries. For the cancer oddity, attention falls on insulin-like growth factor 1, or IGF-1, a hormone that helps muscle grow but which, at higher circulating levels, has been tied to colorectal, prostate and breast cancers. More lifting, more IGF-1, and the benefit may quietly cancel itself out. That, at least, is the working hunch.
It is worth pausing on what this study cannot do. It is observational: it watches, it does not intervene, so it can show association but never quite prove that the dumbbell caused the longer life. People who lift, the data show, also tend to be younger, leaner, less likely to smoke. The exercise was self-reported, which is to say remembered, which is to say imperfect. And the participants were overwhelmingly white health professionals, hardly a cross-section of humanity.
The neurological result, in particular, deserves a raised eyebrow. Dementia takes decades to develop, and people in its long shadow often slow down years before any diagnosis, which could make exercise look protective when the arrow really points the other way. The researchers checked for this, lagging the data by eight years and more, and the link held. Still, dementia on a death certificate is notoriously under-recorded. Caution, then.
What the study does do, rather elegantly, is map how lifting and aerobic exercise stack. Aerobic activity remained the bigger lever by far, cutting death risk by anywhere from a quarter to nearly half on its own. But strength work piled on extra protection at almost every level of aerobic fitness, right up until the very fittest, the ones already clocking enormous aerobic totals, for whom adding weights moved the needle no further. As the authors put it, the pattern “supports current recommendations encouraging both types of activity to maximise mortality benefits.”
For anyone who has eyed the squat rack with suspicion, or assumed that more punishment must mean more reward, there is something almost freeing in all this. The dose that appears to matter most is small, achievable, roughly twenty minutes a day. You do not have to live in the gym. You just, perhaps, have to turn up.
DOI / Source: British Journal of Sports Medicine, 10.1136/bjsports-2025-110503
Frequently Asked Questions
Why is more strength training not always better for living longer?
The study found the protective effect on overall death risk flattened out at around two hours a week, with no further gain above that. For cancer specifically, the benefit appeared only at low volumes and disappeared at higher ones, possibly because heavy training raises levels of a growth hormone linked to certain cancers. The relationship is not a simple “more is better” line, which is partly what makes the finding so interesting.
How much strength training actually makes a difference?
The sweet spot was 90 to 119 minutes a week, roughly twenty minutes a day, which was tied to a 13 percent lower risk of death from any cause. That is a fairly modest, achievable amount rather than punishing daily gym sessions. The detail of how the benefit splits across heart and brain disease is where it gets surprising.
Is lifting weights as good for you as cardio?
Not quite, according to this research. Aerobic exercise remained the stronger protector, cutting death risk by up to nearly half on its own, while strength training added a smaller bonus on top. The lowest risk of all came from doing both, suggesting they work best as a pair rather than rivals.
Can this study prove that lifting weights makes you live longer?
No, and the researchers are upfront about it. This was an observational study that watched people’s habits over decades, so it can show a strong association but cannot rule out that healthier people simply tend to lift more. Confirming cause and effect would need a different kind of trial, which is harder to run over a 30-year span.
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