ENERGY EXPENDITURE, BODY COMPOSITION AND MAXIMAL OXYGEN UPTAKE IN MIDDLE-AGED JAPANESE WOMEN WHO HAVE LONG-TERM HABITS OF EXERCISING / 体力科学

ABSTRACT

The purpose of this study was to examine the effects of long-term habitual exercise on daily total energy expenditure (TEE) and its components, body composition and maximal oxygen uptake (VO₂max) in middle-aged Japanese women. Twenty-eight subjects aged 39 to 58 years were assigned either to a nonhabitual exercise group (Control ; n=12) or a habitual exercise group (Exercise ; n=16). TEE, physical activity level (PAL) and the daily physical activity energy expenditure (PAEE) were assessed by doubly labeled water (DLW) method. The exercise-induced energy expenditure (ExEE) and nonexercise-induced energy expenditure (NExEE) were evaluated based on the activity record investigation conducted simultaneously during the DLW measurement period. The result follows that TEE was significantly (p<0.01) higher in the Exercise group (2520 kcal · day^-1) than in the Control group (1921 kcal · day^-1). There was no significant difference in basal metabolic rate between the groups. PAEE and ExEE were significantly higher in the Exercise group than in the Control group (p<0.01). Habitual exercise induced an increase in TEE without resulting in a compensatory reduction of NExEE. The percentage body fat (fat%) was significantly lower in the Exercise group (25.5%) than in the Control group (30.9%). VO₂max was higher in the Exercise group (1788 ml · min^-1) than in the Control group (1417 ml. min^-1). After correction for body weight, fat% was negatively associated with TEE (p<0.01), PAEE (p<0.01) and ExEE (p=0.05), while VO₂max was positively associated with TEE (p<0.05), PAL (p<0.05), PAEE (p<0.05) and ExEE (p<0.01). These results suggest that habitual exercise is associated with the increase of TEE, the improvement of body composition and VO₂max. The improvement of VO₂max was mainly caused by the increase in ExEE, indicating that the exercise intensity is important to the improvement of cardiorespiratory endurance fitness.