The metabolic syndrome is considered a way of identifying those at increased risk of developing Type 2 diabetes, coronary artery disease, and premature mortality. Previous studies have indicated physical activity to be an effective way to lower some of these risk factors individually, but this is believed to be the first study showing physical activity to simultaneously improve the cluster of factors. "The use of physical activity promotion to treat and prevent the primary risk factors for cardiovascular disease has the potential to have a great public health impact given the high prevalence of inactivity in North America," said Peter T. Katzmarzyk, Ph.D., FACSM, a researcher from Queen's University in Kingston, Ontario, Canada, and lead author of the study. "The results of our study suggest that exercise can be an effective component of lifestyle change that can reduce these dangers." The HERITAGE (Health, Risk Factors, Exercise Training, and Genetics) Family Study is a large multi-center trial conducted in Canada and the United States to study the effects of regular exercise training on risk factors for Type 2 diabetes and cardiovascular disease.

The trial was also designed to investigate the genetics of cardiovascular, metabolic, and hormonal responses to exercise training.

Researchers in the HERITAGE Family Study recruited 855 eligible adult volunteers to participate in a 20-week program of exercise training. Participants had to be sedentary but otherwise of good general health to qualify. The five factors that make up the metabolic syndrome were tested at the beginning and end of the 20-week program. The volunteers rode a stationary bicycle three times a week, and the duration and intensity of the exercise sessions increased as the trial progressed.

At the end of the program, 742 participants had completed the necessary training and 621 provided the necessary measurements for the metabolic syndrome. Of these, 105 were classified as having the metabolic syndrome at baseline. By the end of the program, 32 of these individuals had reduced their risk factors so that they no longer had the metabolic syndrome. Therefore, the overall prevalence of the metabolic syndrome decreased from 16.9 percent to 11.8 percent following training. Furthermore, exercise was an effective way to decrease the risk factors for the individuals in the study regardless of their race or gender.

"The volunteers we found to have the metabolic syndrome were at a high risk of future health problems," added Katzmarzyk. "This study suggests that exercise training represents an important aspect of the prevention of chronic disease."