THE EFFECTS OF ENDURANCE EXERCISE TRAINING ON RESTING METABOLIC RATE IN SEDENTARY, OVERWEIGHT PRE AND POSTMENOPAUSAL FEMALES.

Abstract

782 Five premenopausal (32 ± 10 yrs, 80 ± 11 kg, 41 ± 7% fat) and six postmenopausal women (60 ± 11 yrs, 89 ± 13 kg, 37± 5% fat) performed treadmill walking for forty minutes, three times per week for twelve weeks at 60 - 65% of their heart rate reserve. Four sedentary women (50 ± 12 yrs, 79 ± 14 kg, 39 ± 6% fat) served as control subjects. There were no significant differences in physical characteristics between the groups. Each subject underwent pre-training and post-training measurements of body weight, resting metabolic rate (RMR), body composition, VO2 max, resting plasma thyroid hormones and catecholamines, and seven-day dietary recall. Analysis of variance with repeated measures revealed significant increases in VO2 max (22.3 vs. 25.1 ml/kg/min, n=11, p<0.05) and total body water (29 ± 5 vs. 30 ± 6 L, p<0.05) with no significant changes in body weight, lean body mass or body fat percentage following training. No significant increases were seen in RMR for the training group (n = 11) (1.81 vs. 1.96 ml/kg/min, NS; 137 vs. 143 ml/min, NS; 66 vs. 69 kcal/min, NS) however, there were trends for time by group interactions for RMR in terms of ml/kg/min (p =.069), ml/min (p =.071) and kcal/min (p =.067). No significant changes in plasma catecholamines, thyroid hormones or dietary intake were seen following the training period. These data suggest that exercise training of greater duration and/or intensity may be necessary for the detection of significant changes in RMR and its related hormonal mechanisms in overweight, sedentary women.