A little exercise better than none for heart health

By Dr. Ananya Mandal, MDAug 1 2011

According to a new study getting even a little exercise is better than getting none at all, and this may hold especially true for women.

The U.S government guidelines recommend getting 150 minutes of exercise a week, and the study showed that even people who exercised less than that had a lower risk of coronary heart disease than those who did not exercise. The study showed that people who did 150 minutes of moderate exercise weekly had a 14 percent lower risk of developing coronary heart disease than those who did no exercise. And those who did 300 minutes of exercise a week had 20 percent lower risk of developing coronary heart disease than those who did not exercise. At higher levels of activity, the risk became progressively lower.

“The biggest health benefits we saw were for those who went from doing nothing to those doing something small,” said Jacob Sattelmair, author of the new AHA study. “Even a little bit of activity makes a significant difference.” A little bit means 10 to 15 minutes a day. Sattelmair says the new findings are the first to make quantitative assessments of the amount of physical activity a person needs to reduce risk. “Early studies broke people into groups such as active and sedentary…More recent studies have begun to assess the actual amount of physical activity people are getting and how that relates to the risk of heart disease,” he said.

The study added that the association between more exercise and greater health benefits was stronger in women than it was in men, though it was unclear as to why. It could be that women have an overall lower risk of developing coronary heart disease than men do, so factors other than exercise that are difficult to measure precisely, such as diet, contributed to this effect.

“It's very clear that a little bit of exercise makes a big difference,” said Carol Ewing Garber, author of the ACSM's new guidelines and assistant professor of movement at Columbia University. “The recommendation to get 150 minutes a week of moderate-intensity exercise is still one of the goals, but the message needs to be heard that doing less is also helpful.” Garber says research shows that long durations of physical inactivity during the day raise your risk of developing heart disease, diabetes, cancer and obesity.

This study provides the first evidence supporting the 2008 Physical Activity Guidelines for Americans, issued by the U.S. Department of Health and Human Services, the researchers said. Previous research had shown that physical activity is associated with a 20 percent to 30 percent lower risk of coronary heart disease; however, it was not known how much exercise was needed to lower risks by this amount.

This study is a compilation of results of 33 previously conducted studies of physical activity and heart disease. About 17 million people in the United States had coronary heart disease in 2010, the researchers said.

The study was published today (Aug. 1) in the journal Circulation.