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

Even light exercise can be good for your heart and fitness, but the harder you work—within a low-intensity range—the more you’ll improve. There’s no ‘too easy’ when it comes to getting some benefit from light workouts.

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%.

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