A study by Harvard researchers has clarified the relationship between different types of exercise and the decreased risk of coronary heart disease among men.

The School of Public Health (HSPH) study, whose results were published in yesterday’s Journal of the American Medical Association, assessed the impact of different forms of exercise on a pool of 44,452 healthy men and found that men who weight-train, run or walk briskly exhibit a significantly reduced risk of coronary heart disease compared to those who don’t.

According to Frank Hu, assistant professor of nutrition and epidemiology at HSPH and co-author of the study, the significance of the research stems from its focus on how exercise of different types and at different levels of intensity lowers men’s risk of heart disease.

“Everyone knows that exercise decreases the risk of heart disease,” he said. “But now, we have a clearer understanding of what types of exercise are better than others to reach that end.”

To determine the role that the type and intensity of exercise plays in reducing the risk of coronary heart disease, participants in the study were monitored via questionnaires every two years from 1986 to 1998.

The results indicated that men who trained with weights for 30 minutes or more per week lowered their risk of coronary heart disease by 23 percent.

This finding was one revolutionary aspect of the study, said HSPH spokesperson Kevin Myron.

“People have always thought that running and aerobic activity were good for your heart,” Myron said. “But now weight-lifting has proven beneficial to reduced risks as well.”

Hu and his research partner, Mihaela Tanasescu, a former HSPH graduate student, also determined that men who ran for an hour or more per week reduced their risk by 42 percent, while those who walked briskly for 30 minutes or more lowered their potential risks by 18 percent.

“Higher intensities of exercise are associated directly with decreased risks,” said Hu, who has spent years researching the connection between nutrition and exercise and the prevention of diabetes.

“The best way for men to reduce the risk of CHD is to increase the amount of the exercise, increase the intensity of the exercise and add weight-training to their exercise program,” he said.

The study, which also found that physically active men have lower body mass indexes, lower fat intake and lower incidences of smoking and high blood pressure, will likely continue with follow-up research to determine the impact of other types of exercise on men and women with preexisting medical conditions like diabetes.

“Intriguing studies usually breed other cohorts,” Myron said. “I wouldn’t be surprised to see further research at the HSPH that seek to pinpoint the impact of other specific forms of exercise on men and women.”