If you're trying to get or stay in shape, you've probably heard that walking 10,000 steps a day can do the trick. But maybe you've found that the recommendation, which the American College of Sports Medicine promoted in the 1990s and has since been widely adopted by exercise-promotion campaigns, isn't doable in your busy life — or that it doesn’t raise your heart rate enough to reduce your risk of cardiovascular disease.

Today, you've got additional guidelines to go on that may make whatever walking you do more heart-healthy. Walking 3,000 steps over 30 minutes, five days a week — or 1,000 steps for 10 minutes a day — can get your heart pumping enough to cut your risk of heart disease, according to research in the May issue of the American Journal of Preventive Medicine.

"There's very little, if any evidence to say 10,000 steps is a magical number," says study co-author Simon Marshall, an associate professor of exercise and nutritional science at San Diego State University who developed the guidelines with a grant from the Centers for Disease Control and Prevention (CDC). "What it does is give people a way to know if they're being active at an intensity that’s going to be good for their health. That level is quite important because all the studies tell us that unless you're exercising in a way that stresses the cardiovascular system to a certain level, you're less likely to have a disease benefit. The best bang for your buck is something of moderate intensity."

Health officials will consider the findings when they draft future exercise recommendations, CDC spokesperson Karen Hunter says.

Marshall came up with the guidelines after putting 97 adults on a treadmill and measuring how many steps they had to take per minute to achieve a moderate level of physical activity, defined as consuming three times the amount of oxygen as a person would while sitting in a chair.

The recommendations don't mean you have to press any new buttons on your pedometer. But you might want to combine your pedometer with a watch: Instead of merely trying to rack up 10,000 steps a day, Marshall tells ScientificAmerican.com, think about building a heart-healthy level activity into your routine. Figure out a regular walking route during which you take 1,000 steps. Then, try to get through those steps in 10 minutes — and walk them every day.

"Walking 3,000 steps in 30 minutes could be more beneficial to your health than walking 10,000 steps, period," Marshall says. "You're guaranteeing walking at a pace that's beneficial to your heart."

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