Objective: To evaluate the training effects of Chinese shadow boxing, Tai Chi Chuan (TCC), on the maintenance of cardiorespiratory function in older individuals.
Design: Prospective study of a cohort of TCC practitioners and a group of sedentary controls examined 2 years after initial examination.
Setting: Research project at a hospital-based exercise physiology laboratory.
Participants: Eighty-four community-dwelling older adults (mean age: 64 +/- 9 years) with no significant cardiovascular, pulmonary, and musculoskeletal disease completed this study. The TCC group, 23 male and 22 female subjects, had been practicing TCC regularly for 6.7 +/- 3.3 years. The control group included 21 male and 18 female sedentary subjects with age and body size matched to the TCC group.
Intervention: During the period of the study, the TCC practitioners practiced TCC 5.0 +/- 1.1 times per week. Each session included 20 minutes of warm up, 24 minutes of TCC training, and 10 minutes of cool down. The baseline cardiorespiratory function was recorded in the initial exercise test. The same measurements were repeated 2 years later to determine the rate of decline of cardiorespiratory function. Furthermore, heart rates (HR) were monitored in 18 men and 16 women during the performance of TCC to determine the exercise intensity of TCC.
Main outcome measure: The study measured 2-year trends of cardiorespiratory function in both groups.
Results: In the TCC group, the males showed a 2.8% decrease in maximal oxygen uptake (VO2max) from 31.6 +/- 7.6 mL x kg-1 x min-1 to 30.7 +/- 7.1 mL x kg-1 x min-1; the females showed a 2.9% decrease in VO2 max from 20.7 +/- 2.3 mL x kg-1 x min-1 to 20.1 +/- 2.5 mL x kg-1 x min-1. In contrast, the male control group showed a 6.6% decrease in VO2max from 24.4 +/- 4.4 mL x kg-1 x min-1 to 22.8 +/- 4.4 mL x kg-1 x min-1; the females showed a 7.4% decrease in VO2max from 16.2 +/- 2.3 mL x kg-1 x min-1 to 15.0 +/- 2.7 mL x kg-1 x min-1. At the ventilatory threshold (VeT), the sedentary group also showed a significant decrease in VO2. During the steady-state performance of TCC, subjects' mean HR was approximately the HR at the VeT (53-57% of HRmax reserve).
Conclusion: The data substantiate that practicing Tai Chi Chuan regularly may delay the decline of cardiorespiratory function in older individuals. In addition, TCC may be prescribed as a suitable aerobic exercise for older adults.