Lori B. Aiken

Effects of the Amount of Exercise on Body Weight, Body Composition, and Measures of Central Obesity STRRIDE—A Randomized Controlled Study

Background Obesity is a major health problem due, in part, to physical inactivity. The amount of activity needed to prevent weight gain is unknown. Objective To determine the effects of different amounts and intensities of exercise training. Design Randomized controlled trial (February 1999–July 2002). Setting and Participants Sedentary, overweight men and women (aged 40-65 years) with mild to moderate dyslipidemia were recruited from Durham, NC, and surrounding communities. Interventions Eight-month exercise program with 3 groups: (1) high amount/vigorous intensity (calorically equivalent to approximately 20 miles [32.0 km] of jogging per week at 65%-80% peak oxygen consumption); (2) low amount/vigorous intensity (equivalent to approximately 12 miles [19.2 km] of jogging per week at 65%-80%), and (3) low amount/moderate intensity (equivalent to approximately 12 miles [19.2 km] of walking per week at 40%-55%). Subjects were counseled not to change their diet and were encouraged to maintain body weight. Main Outcome Measures Body weight, body composition (via skinfolds), and waist circumference. Results Of 302 subjects screened, 182 met criteria and were randomized and 120 completed the study. There was a significant ( P Conclusions In nondieting, overweight subjects, the controls gained weight, both low-amount exercise groups lost weight and fat, and the high-amount group lost more of each in a dose-response manner. These findings strongly suggest that, absent changes in diet, a higher amount of activity is necessary for weight maintenance and that the positive caloric imbalance observed in the overweight controls is small and can be reversed by a modest amount of exercise. Most individuals can accomplish this by walking 30 minutes every day.

Minimal versus umbilical waist circumference measures as indicators of cardiovascular disease risk.

Objective: Measures of central obesity are strongly correlated with cardiovascular disease (CVD) risk. Although waist circumference (WC) is a commonly used measure of central obesity, there is no standard measurement location. We examined two WC locations to determine which was more highly correlated with CVD risk factors and metabolic syndrome (MS).