Increased physical activity associated with lower CHD risk for overweight women

Increased physical activity reduced the risk for coronary heart disease in women who were overweight and obese but did not eliminate it, according to results from a new study.

Researchers from Beth Israel Deaconess Medical Center and other sites in Massachusetts studied the interaction between CHD and physical activity in 38,987 women who participated in the Women’s Health Study. The study began in 1992 and the researchers followed the participants for an average of 10.9 years. All women reported their height and weight, average time per week spent exercising, health habits and medical history at baseline and completed regular follow-up questionnaires about heart events and risk factors over the course of the study period.

At baseline, 34% of women were considered physically active based on the Surgeon General’s guidelines, 31% were considered overweight and 18% were considered obese. Over the course of the study period, 948 women developed CHD.

Physical activity and body mass index were both associated with increased risk for CHD. Active women of normal weight had the lowest risk, followed by inactive, women of normal weight. Inactive women who were overweight or obese had the highest risk.

“We postulate that the beneficial effect of physical activity may directly reduce and combat the ill effect of the prothrombotic factors released by adipocytes,” the researchers wrote.

Physical activity also may improve blood vessel function and reduce the risk for blood clots. However, physical activity did not eliminate the negative effects of being overweight.

“Even high quantities of physical activity are unlikely to reverse the risk for CHD in women who are overweight and obese without concurrent weight loss,” the researchers wrote, and they suggested counseling women to engage in regular physical activity and healthy habits to reduce their risk for CHD. – by Katie Kalvaitis

Arch Intern Med. 2008;168:884-890.