Resting metabolic rate and postprandial thermogenesis by level of aerobic fitness in young women

Abstract:

Resting metabolic rate (RMR) and the thermic effect of a meal (TEM) were compared among women of three levels of aerobic fitness. Twenty-three euthyroid, eumenorrheic women (aged 18-35 years) were divided into three groups based on VO2 max standardized for fat-free weight (FFW), as determined from a graded exercise test: High Fit (HF): n = 7, VO2 max > 70 ml(*)kg FFW(-1*)min-1; Moderately Fit (MF): n = 8, VO2 max = 55-70ml(*)kg FFW(-1*)min-1; and Low Fit (LF): n = 8, VO2 max < 55ml(*)kg FFW(-1*)min-1). At 0700h RMR was measured for 1h by indirect calorimetry with subjects in a fasted, preovulatory state, having refrained from exercise on the preceding day. The subject then consumed a liquid meal (12 kcal(*)kg FFW-1) and indirect calorimetry was continued for 3 h to determine the TEM. RMR adjusted for FFW using analysis of covariance was significantly higher (P < 0.05) in the HF group (X ± SEM = 1.08 ± 0.03 kcal(*)min-1) compared to the MF (0.99 ± 0.04) and LF (0.90 ± 0.04) groups. Group differences in the thermic response did not reach statistical significance, although there was a trend for a high TEM in the HF group. There was a positive relationship between RMR and energy flux (average daily kcalorie intake + daily kcaloric expenditure in physical activity). These results suggest that women who exhibit high levels of exercise and aerobic fitness may be less energy efficient during the non-exercise portion of the day then their less active counterparts.

Año de publicación:

1993

Keywords:

Fuente:

scopus