(CBS) A little exercise can do a lot for your heart. That's the message from Harvard researchers after a new study showed that as little as 2.5 hours of exercise a week can dramatically cut heart disease risk.
The U.S. Department of Health and Human Service recommends 2 hours 30 minutes of exercise per week. Researchers looked at 33 studies on exercise's benefits to see if working out for that amount of time reduced heart disease risk for the study published in the August 1 issue of Circulation. Their analysis found that 2 hours 30 minutes of exercise cut heart disease risk by 14 percent. Even people who exercised less than the recommended time allotment decreased their risk more than those that did nothing.
"The overall findings of the study corroborate federal guidelines - even a little bit of exercise is good, but more is better," Dr. Jacob Sattelmair, an epidemiologist at the Harvard School of Public Health, said in a written statement.
How much better? Exercising for 300 minutes a week decreased heart disease risk by 20 percent, 750 minutes cut the risk by 25 percent. The protective benefit was found to be even greater for women.
The authors say this is the first study to quantify how much exercise is needed to cut heart disease risk.
"The biggest bang for your buck is at the lower ends of physical activity," Sattelmair told HealthDay. "If you went from none to 2.5 hours a week, the relative benefit is more than if you went from, say, 5 to 7.5 hours a week.
Heart disease is the number one killer in the U.S. taking more than 631,000 lives each year -one in four deaths. It's caused by plaque buildup in the coronary arteries which impedes blood flow, resulting in a potentially deadly heart attack.
Besides exercise, maintaining a healthy weight, eating a low-salt diet that's rich in fruits and vegetables, and not smoking are ways to reduce heart disease risk.
WebMD has more on exercise and heart disease.