Exercise Without Weight Loss Can Reduce Cardiovascular Risk

Moderate exercise can significantly lower the risk of heart disease in overweight and mildly obese adults, even if the physical activity does not lead to weight loss, according to a pilot study conducted at the Duke University Medical Center in Durham, North Carolina. Study participants saw a reduction in low density lipoprotein (LDL) cholesterol—the so-called “bad” cholesterol—and an increase in high density lipoprotein (HDL) cholesterol —“good” cholesterol—after 3 months of a controlled exercise program. They also saw a decrease in percent body fat, even as their weight remained unchanged.

The pilot study, led by Duke cardiologist William Kraus, M.D., showed that exercise alone can significantly improve risk factors for cardiovascular disease. “We now have the data for physicians who can tell their patients that they shouldn’t focus so much on the scale,” Dr. Kraus said. “These patients should not become discouraged and give up exercising, because our study shows that these patients are getting healthier even if they don’t lose any weight.”

Three women and four men aged 40 to 55 participated in the study. Aside from elevated cholesterol and body mass indexes of 25 to 35 indicating overweight to obesity, the participants were in good health, were non-smokers, and did not have clinical histories of heart disease. For 3 months, these previously inactive adults exercised for 1 hour 4 days per week, expending about 2000 calories per week. Their weight and diets were monitored to prevent weight loss or gain.

By the end of the study, participants showed a 4.34 percent decrease in body fat, which the researchers believe was converted to lean muscle mass. LDL cholesterol levels decreased in six of the seven participants on average from 122 mg/dl to 104 mg/dl, while HDL cholesterol increased from 32 mg/dl to 37 mg/dl. Despite the small number of study participants, the consistent results across all participants make these findings statistically significant.

“This pilot study was a first attempt to isolate the effects of exercise from weight loss in a controlled fashion,” Dr. Kraus said. “We designed the trial such that we can attribute all the beneficial effects to exercise alone.” The results of the study provide the scientific basis for a larger trial, Studies of Targeted Risk Reduction Interventions through Defined Exercise (STRRIDE), which is being conducted with a $4.3 million grant from the National Heart, Lung, and Blood Institute.

The published study is in the February 2000 issue of the journal Clinical Exercise Physiology, and can be ordered online at www.hkusa.com or by telephone at 1-800-747-4457. s