Doing short bursts of intense exercise might boost heart fitness more than steady, moderate workouts for people with heart disease — on average by a small but measurable amount.

For people with heart disease, short bursts of intense exercise don’t seem to work much better than steady, moderate exercise when both burn the same number of calories — both help a bit, but the difference between them is tiny.

Doing steady, moderate exercise regularly can noticeably boost your fitness level — especially if you're out of shape or older — with real improvements in how well your body uses oxygen after just a few weeks.

Doing short bursts of intense exercise for 12 weeks doesn't improve the maximum oxygen your body can use during exercise in people with excess body fat, even though they can exercise longer before getting tired.

Doing steady, moderate workouts might boost your heart and lung fitness more than super intense but short sprints, even though the moderate workouts take longer.

Doing light, steady exercise like brisk walking regularly can significantly boost your heart and lung fitness—even if you're just starting out. That kind of improvement could lower your risk of dying from any cause by over 10%.