How much strength training do you need?
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Two sessions a week, about an hour in all to start and up to two hours. In 147,374 US adults, the risk of death was lowest at 90 to 119 minutes of lifting a week and stopped falling past two hours. A review of 16 studies found it lowest near 40 minutes. In both, walking enough did more than lifting alone.
The headlines don’t help. One study says 30 minutes a week, another says 90, and a university press release says “up to 45%” without mentioning that the 45% needed a lot of walking too. So people either think they need hours they don’t have, or that if some lifting is good, more must be better.
What we’d do
Lift twice a week for 30 to 45 minutes each time, every big muscle. That’s about an hour a week, the middle of what both big studies found. Go up to two hours if you love it. Past that, put the extra time into walking, since walking 150 minutes a week went with a bigger drop in deaths than any amount of lifting did on its own.
If you remember three things
- Two sessions a week is the US guideline, and only about one in three US adults does it (32.9% in 2024).
- The benefit flattens fast. 90 to 119 minutes a week went with 13% lower risk of death, and over two hours with 8%.
- Walking did more than lifting. Enough walking with no lifting went with 26% fewer deaths. Plenty of both went with about 45% fewer.
What does the US guideline say?
The Physical Activity Guidelines for Americans (2018) ask adults for muscle-strengthening activity of moderate or greater intensity, working all the major muscle groups, on 2 or more days a week. That’s on top of 150 to 300 minutes of moderate aerobic activity a week, like brisk walking, or 75 to 150 minutes of vigorous activity. Lifting weights and push-ups both count. In 2024, 32.9% of US adults met the strength part, up from 31.9% in 2020.
A picture from daily life
Sleep is a good way to think about it. Going from 4 hours a night to 7 changes your whole day. Going from 9 to 11 doesn’t make you feel any better, and you’ve lost two hours.
Lifting looks the same in the studies. The first hour a week does most of the good. The third hour adds little or nothing.
The Harvard study
In June 2026, researchers at Harvard published the biggest study yet of lifting and lifespan. They used three long-running US studies of nurses and other health professionals, 147,374 people (31,540 men and 115,834 women), who answered questions about their exercise every 2 to 4 years for up to 30 years. By the end, 35,798 had died. About 46% said they did some weight or resistance training.
After taking their walking and other aerobic exercise into account, this is how much lower their risk of death was than people who didn’t lift.
At 90 to 119 minutes a week, deaths from heart disease were 19% lower and deaths from diseases of the brain and nerves 27% lower. Cancer deaths were lower only at the smaller doses, under an hour a week. Past 120 minutes, the press release says, more lifting “did not appear to provide any additional benefit”. Put in your own minutes.
The surprise in the study is walking
The researchers also split people by lifting and by aerobic exercise at the same time. Aerobic exercise is counted in MET-hours, and 150 minutes of brisk walking a week is 7.5. This grid shows how much lower the risk of death was than for people who did neither (top left). Darker is lower.
| Aerobic MET-hours a week | No lifting | 1 to 59 min | 60 to 119 min | 120+ min |
|---|---|---|---|---|
| Under 7.5 | Compared with | 7% lower | 11% lower | 3% lower |
| 7.5 to 15 | 26% lower | 27% lower | 30% lower | 31% lower |
| 15 to 30 | 32% lower | 38% lower | 44% lower | 39% lower |
| 30 to 45 | 37% lower | 41% lower | 45% lower | 47% lower |
| 45 or more | 43% lower | 47% lower | 43% lower | 42% lower |
Look down the first column and then across the top row. Moving from almost no aerobic exercise to the guideline’s 150 to 300 minutes of walking, with no lifting at all, went with 26% fewer deaths. The best lifting cell in the top row, people who lifted but barely walked, went with 11% fewer. Walking enough did more than twice as much as lifting did alone.
The darkest cells are people who did plenty of both. Keep in mind how much aerobic exercise those rows are, though. 30 MET-hours a week is about 10 hours of brisk walking, or 5 of running.
The second opinion
A 2022 review pooled 16 studies that followed people over time. Any muscle-strengthening activity went with 15% lower risk of death from any cause, 17% lower from heart disease and 12% lower from cancer. The curve was J-shaped. The risk was lowest near 40 minutes a week (17% lower) and stayed below no lifting up to about 140 minutes. People who did both lifting and aerobic exercise had 40% lower risk than people who did neither.
The two biggest bodies of evidence agree on the shape and differ on where the bottom sits, somewhere between about 40 and 120 minutes a week. An hour a week to start, and two at most, fits both.
How many days?
Two is the guideline, and it’s plenty. A 2018 pooled analysis of 22 studies found that people who trained more days a week gained more strength, but only because they did more sets. When the total sets were the same, spreading them over more days made no difference. If two long sessions are hard to fit in, three shorter ones work just as well. How many days a week should I lift?
Is more than two hours bad for you?
The worry
The curve goes back up. In both studies the people who lifted the most had less benefit than people who lifted a moderate amount.
What the numbers say
They were still better off than people who didn’t lift. At 120 minutes or more, risk was 8% lower than no lifting, and in the review it stayed below no lifting up to about 140. Few people lift that much, so those estimates are less certain, and nobody knows yet why the curve bends. It’s no reason to stop lifting, only a sign that extra hours don’t buy more.
What these studies can’t tell you
People chose how much to lift, and people who lift tend to differ from people who don’t in ways a questionnaire can’t fully catch. The Harvard cohorts were mostly white, middle-aged and older health professionals, and their exercise was self-reported. The review’s authors rated their certainty for death from any cause as very low, which is the usual grade for studies that follow people instead of assigning them. None of this gives you a personal risk, and no study here adds a number of years to anyone’s life. What the trials do show is that lifting builds the strength and balance that go with a long life in these studies.
More detail: what a MET-hour is
A MET is how hard an activity is compared with sitting still. The CDC counts moderate activity, like walking at 2.5 miles an hour or faster, as 3 to 5.9 METs, and vigorous activity, like running, as 6 or more. Counting a moderate minute as 3 METs and a vigorous one as 6, 150 minutes of brisk walking comes to exactly 7.5 MET-hours a week, the line the Harvard team used for enough aerobic exercise.
Lifting is half of a good week. For the whole week, cardio included, see exercise.guide, and vo2max.guide for aerobic fitness.
8 sources
- Zhang Y and others, Long-term resistance training with all-cause and cause-specific mortality, British Journal of Sports Medicine, 2026pmc.ncbi.nlm.nih.gov
- Harvard T.H. Chan School of Public Health, Moderate amount of strength training each week could boost longevity, 2026hsph.harvard.edu
- Momma H and others, Muscle-strengthening activities are associated with lower risk and mortality in major non-communicable diseases, British Journal of Sports Medicine, 2022pmc.ncbi.nlm.nih.gov
- US Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition, executive summary, 2018odphp.health.gov
- US Department of Health and Human Services, Top 10 things to know about the second edition of the Physical Activity Guidelines for Americansodphp.health.gov
- Healthy People 2030, PA-04: adults who do enough muscle-strengthening activity (NHIS)odphp.health.gov
- Centers for Disease Control and Prevention, Measuring physical activity intensitycdc.gov
- Grgic J and others, Effect of resistance training frequency on gains in muscular strength, Sports Medicine, 2018europepmc.org
