Effects of diet and exercise on energy expenditure in postmenopausal women

Abstract

The purpose of this study was to determine the effect of a 24-wk diet + exercise (DE) or diet-only program on basal metabolic rate (BMR), bone mineral density (BMD), energy expended during daily activities, muscle strength, and maximal oxygen consumption (VO2max) in 40 postmenopausal women. Daily energy need was determined by measuring BMR and assessing physical activity with 8-d self-reported activity records. The DE group consumed 2092 kJ/d less than the daily energy need and walked and performed strength-training exercises during which they expended an additional 837 kJ/d. The two diet-only groups consumed either 2092 kJ/d (D-2092) or 2929 kJ/d (D-2929) less than the daily energy need. BMD, BMR, muscle strength, VO2max, and energy expended during lying, sitting, standing, and walking were measured at baseline and after 12 and 24 wk of treatment. A significant decrease in BMR and energy expended during sitting and walking occurred in all groups, with no significant differences observed among groups. Although the declines in BMR were significant, they were small and may not have been physiologically relevant. No changes in BMD or VO2max occurred, whereas strength increased significantly in the DE group. The results showed that postmenopausal women significantly improved their body composition over a period of 6 mo without experiencing a large decline in BMR, BMD, or select components of energy expenditure.