More research shows that even small amounts of aerobic exercise help lower coronary heart disease risk, according to a review published Monday in Circulation, the journal of the American Heart Association.
The mega-study is part of a growing body of research showing that some physical activity provides health benefits -- even when levels fall below the recommended federal guidelines of 150 minutes of moderate-intensity physical activity a week. For the first time since 1998, the American College of Sports Medicine updated its exercise guidelines in June, including information on how little exercise is needed to achieve health benefits.
"The biggest health benefits we saw were for those who went from doing nothing to those doing something small," says Jacob Sattelmair, author of the new AHA study. "Even a little bit of activity makes a significant difference" -- and a little bit means 10 to 15 minutes a day.
Sattelmair says the findings are the first to make quantitative assessments of the amount of physical activity a person needs to reduce heart risk.
"Early studies broke people into groups such as active and sedentary," Sattelmair says. "More recent studies have begun to assess the actual amount of physical activity that people are getting and how that relates to the risk of heart disease."
The sports medicine college's guidelines also say that as little as half -- about 75 minutes a week -- can be helpful, while stressing that more is needed to maintain a healthy weight and achieve maximum benefits.
"It's very clear that a little bit of exercise makes a big difference," says Carol Ewing Garber, author of the 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."
The findings published Monday in Circulation do not list a percentage for the magnitude of lower heart disease risk for those who meet half the guideline because of the methodology used, Sattelmair says.
Also noted in the study:
People who do 150 minutes of moderate intensity (or 75 minutes of high intensity) exercise have a 14% lower risk of heart disease compared with sedentary people. "That's not as robust as people might expect, but it's still significant," Sattelmair says.
There's a progressive reduction of risk to heart health. If you do twice the guidelines (300 minutes), you lower your risk 20%. If you do 750 minutes, the risk drops to 25%. "It's feasible to rack up two hours of movement a day," Sattelmair says. "That's clearly what we're designed to do."
Women received more benefit from exercise. "We did not have a good explanation for why this is," Sattelmair says. He adds that more research is necessary.
Though it's not part of the new findings, breaking up the day with exercise is also key to establishing good health, Sattelmair says. Several studies have shown that meeting the guidelines of 150 minutes a week is not enough if you spend the rest of your time on the sofa or sitting at a computer.
To see more of USAToday.com, or to subscribe, go to http://www.usatoday.com
Copyright 2011 USA TODAY, a division of Gannett Co. Inc.