What the New Study on Exercise and Longevity Really Tells Us

January 30, 2026

Harvard scientists find that exercise variety is good but not too much and only certain types. Take the findings with a grain of salt.

The study was very widely covered in the media and extensively discussed on social media. The main message, as highlighted in the accompanying press release from Harvard, where the researchers are based, is that doing a variety of different types of exercise is healthier than doing just one thing, regardless of how much you do. But commenters were also fascinated by a series of colorful graphs plotting dose-response curves for individual types of exercise, purporting to show that walking is the best, jogging is good but not too much, swimming is no good at all, and so on. And more generally, the results even hint that beyond a relatively modest amount of weekly exercise, doing more of anything doesn’t help you.

It’s worth taking a closer look at these results, because they convey some important lessons about what exercise does for us, what it doesn’t do, and why even massive, long-running studies can lead us astray if we don’t interpret them carefully. There are three key claims: that too much exercise is bad; that certain types of exercise are uniquely bad; and that doing a variety of exercises is best. Outside