How much is enough?

What your result means

The tool puts your usual week in a group from the study. Lifting 90 to 119 minutes a week went with the lowest risk of death, and more than that added nothing. If your walking is short of 150 brisk minutes, your next minutes do the most there, since enough walking went with a bigger drop than any amount of lifting alone. These were people who chose their own exercise, so the grid shows a dose to aim for and says nothing certain about your own risk.

If you lift less than an hour a week, add a second session from the strength protocol. If you lift enough and walk little, add walks before you add lifting. exercise.guide covers how much exercise you need in all.

The study behind it

Researchers at Harvard followed 147,374 US health professionals (31,540 men and 115,834 women) for up to 30 years, asking every few years how much time they spent on weights and on aerobic exercise. 35,798 died over that time. With aerobic exercise taken into account, lifting 90 to 119 minutes a week went with 13% lower risk of death than no lifting, and more than 120 minutes added nothing. Walking enough, 150 brisk minutes a week, went with a bigger drop than any amount of lifting alone, and the lowest risk of all was in people who did both.

Aerobic exercise is counted in MET-hours: a brisk-walking minute at 3 METs and a running minute at 6, CDC's lower bounds, so 150 minutes of brisk walking is exactly 7.5 MET-hours, the study's line for enough.

Read it the right way

These people chose their own exercise and reported it themselves, and they were mostly white, middle-aged and older health professionals. The grid shows what happened to groups, never your personal risk, and no number here adds years to a life. A 2022 review of 16 studies found the lowest risk near 40 minutes of lifting a week, still below no lifting up to about 140, so an hour a week to start and up to two is true to both.

More on the Harvard strength study