GENDER DIFFERENCES IN ENERGY EXPENDED DURING ACTIVITIES AND IN DAILY ENERGY-EXPENDITURE OF ELDERLY PEOPLE

Gender effects on energy expended during light seated activities, walk ing, cycling, and sleep and their consequences on daily energy expendi ture (EE) were examined in 11 men and 15 women aged 66.4 +/- 7.1 yr. T wo open-circuit whole body calorimeters were used for EE measurements, except for cycling, during which EE was measured separately with the use of a face mask. Lean body mass (determined using (H2O)-O-18 diluti on method), fat mass, usual physical activity level, and activity inte nsity (e.g., walking speed and cycling power output) were taken as cov ariates in the analysis of EE variations before studying gender effect s. Sleeping metabolic rate (SMR) and daily EE, adjusted for difference s in all covariates, were 11.2 (P = 0.005) and 8.7% (P = 0.071) lower in women than in men, respectively. No gender-related differences were found in the various physical activity EEs above SMR (e.g., gross EE - SMR) [light seated activities (P = 0.790), walking(P = 0.263), and c ycling (P = 0.287)] and daily physical activity EE above SMR (P = 0.58 7) after adjustment for differences in all covariates. Therefore, the lower adjusted daily EE of women could be related to their lower SMR, the most reliable criterion of whole body metabolic rate.