Effects of circuit exercise and Tai Chi on body composition in middle-aged and older women.

AIM: To investigate the impact of circuit exercise and Tai Chi exercise on body composition in middle-aged and older women. METHODS: The present cohort study included 180 women (aged 45-75 years) who were divided into a circuit exercise group, Tai Chi group and control group. The exercise program consisted of 60 min of exercise three times per week for 12 weeks. The circuit exercises were carried out with intensity controlled by heart rate (60-80% of work). The Tai Chi group practiced Yang style with the same frequency, but with intensity of 50-60% of work. Blood pressure and body composition were assessed. The differences in all variables and the relative changes between baseline and 12 weeks' follow up were evaluated. RESULTS: The circuit exercise group showed a significant decrease in body mass index, systolic blood pressure and body fat mass, and an increase in total body muscle mass, lean body mass, bone mineral content and basal metabolic rate. The Tai Chi group showed a decrease in systolic blood pressure. Increases in the basal metabolic rate (1.3 ± 3.0%), total body muscle mass (1.8 ± 4.3%), lean body mass (1.9 ± 4.3%) and bone mineral content (1.8 ± 4.2%), and decreases in body mass index (-2.2 ± 7.8%), body fat (-6.5 ± 10.7%) and diastolic pressure (-1.2 ± 9.4%) were significantly greater in the circuit exercise group than in Tai Chi or control group. CONCLUSION: Circuit exercise for 12 weeks increases lean body mass and basal metabolic rate more effectively than Tai Chi exercise.