MONDAY, Oct. 5, 2015 (HealthDay News) -- When it comes to preventing heart failure, the more exercise, the better.

How much more? A new study suggests maybe as much as two to four times the U.S. minimum recommended levels of 150 minutes of moderate physical activity a week.

The researchers reviewed 12 studies from the United States and Europe that included more than 370,000 people who were followed for an average of 15 years.

People who did two to four times more exercise than the U.S. minimum activity recommendations lowered their risk of heart failure by 20 percent and 35 percent, respectively, the researchers found.

The U.S. recommended minimum levels of exercise were associated with only a slight decrease in heart failure risk, the researchers found.

The study was published Oct. 5 in the journal Circulation.

"Walking 30 minutes a day as recommended in the U.S. physical activity guidelines may not be good enough -- significantly more physical activity may be necessary to reduce the risk of heart failure," said senior study author Dr. Jarett Berry. He is an associate professor of internal medicine and clinical sciences at the University of Texas Southwestern Medical School in Dallas.

Overall, the more people exercised, the lower their risk of heart failure.

"Future physical activity guidelines should take these findings into consideration, and potentially provide stronger recommendations regarding the value of higher amounts of physical activity for the prevention of heart failure," study lead author Dr. Ambarish Pandey, a cardiology fellow at University of Texas Southwestern Medical School, said in a journal news release.

Berry added: "If you look at the general population, we've had tremendous success in reducing coronary heart disease over the last 30 years. But heart failure rates have not declined enough. The findings from the present study suggest that higher levels of physical activity may help combat this growing burden of heart failure."

In heart failure, the heart cannot supply adequate amounts of blood to the rest of body, resulting in shortness of breath and reduced ability to exercise, the researchers explained.

More information

The U.S. National Heart, Lung, and Blood Institute has more about heart failure prevention.