Just not down for that half-hour jog? No problem. Talk a walk instead. A surprising new study shows that brisk walking has the same heart-health benefits as running – as long as you hoof it twice as long. Researchers compared 33,000 runners and 15,000 walkers over six years and found that the same energy used for high-intensity running and moderate-intensity walking yielded similar decreases in high blood pressure, high cholesterol, diabetes, and heart disease risks.

Unlike previous studies that have compared running and walking by time, this trial measured energy exertion by distance traveled. In other words, running three miles was pitted against walking three miles. "You need to walk about 50 percent farther than you would run, and that takes twice as long, but for the same amount of energy expended, the heart benefits are the same," says Paul Williams, study coauthor and a researcher at Lawrence Berkeley National Laboratory in Berkeley, California.

So if you're tight on time in the morning or you want to bust out a quick workout before making dinner, stick with running. But when you have more time to kill, want to shake up your routine, or just give the knees and hips a break from pounding the pavement, by all means walk. Your heart won't mind.