Pounding away for hours on the treadmill is good for you, but it doesn’t give your heart a thorough workout—quick, high-intensity sessions do that best. Exercise is good for us because it puts a strain on the body, prompting it to toughen up for the next punishment. A violinist knows that the skin on their fingertips gets thicker and tougher after several weeks’ practice, and so it is with exercise—the heart beats harder, lungs inflate more, and blood flows more smoothly around the body.

Cardio (short for “cardiovascular”) exercise specifically targets these body systems. What you might think of as cardio exercises—running or swimming—certainly get your heart pounding and lungs working, but this kind of activity is actually better at strengthening your endurance muscles so they can work for longer.

Instead, what’s best for your heart is short bursts of very vigorous, gasping-with-all-you’ve-got exercise, such as high-intensity interval training (HIIT). Putting your heart and lungs under blasts of intense strain, as if you were a cheetah suddenly chasing a gazelle after a day lounging in the sun, heightens the body’s repairing and strengthening responses. These exercises will lower levels of artery-clogging cholesterol and protect you against diabetes, and you’ll receive a particularly huge splurge of the feel-good, mind-enhancing protein BDNF (brain-derived neurotrophic factor) to boot.

Here's a YouTube video.