You probably have a vague sense that exercise is good for you—and you’ve probably heard that it’s “healthy for the heart.” But if you’re like most people, that’s not enough motivation to get you to break a sweat with any regularity. As I report in the TIME cover story, “The Exercise Cure,” only 20% of Americans get the recommended 150 minutes of strength and cardiovascular physical activity per week, more than half of all baby boomers report doing no exercise whatsoever, and 80.2 million Americans over age 6 are entirely inactive.
Whether we’re fully conscious of it or not, we’re always looking for how to be happy. And exercise is one of the most obvious steps to take, as it’s not a coincidence that you feel better after a good workout: It’s science. A Penn State University study found that people who exercised, whether it was a mild, moderate or vigorous workout, had more pleasant feelings than those who didn’t. (1)