2-YEAR TRENDS IN CARDIORESPIRATORY FUNCTION AMONG OLDER TAI-CHI-CHUANPRACTITIONERS AND SEDENTARY SUBJECTS

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 pra ctitioners and a group of sedentary controls examined 2 years after in itial examination. SETTING: Research project at a hospital-based exerc ise physiology laboratory. PARTICIPANTS: Eighty-four community-dwellin g older adults (mean age: 64 +/- 9 years) with no significant cardiova scular, pulmonary, and musculoskeletal disease completed this study. T he 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 an d 18 female sedentary subjects with age and body size matched to the T CC group. INTERVENTION: During the period of the study, the TCC practi tioners practiced TCC 5.0 +/- 1.1 times per week. Each session include d 20 minutes of warm up, 24 minutes of TCC training, and 10 minutes of cool down. The baseline cardiorespiratory function was recorded in th e initial exercise test. The same measurements were repeated 2 years l ater to determine the rate of decline of cardiorespiratory function. F urthermore, heart rates (HR) were monitored in 18 men and 16 women dur ing the performance of TCC to determine the exercise intensity of TCC. MAIN OUTCOME MEASURE: The study measured 2-year trends of cardiorespi ratory function in both groups. RESULTS: In the TCC group, the males s howed a 2.8% decrease in maximal oxygen uptake (VO(2)max) 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 VO(2)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 VO(2)max 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 fem ales showed a 7.4% decrease in VO(2)max 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 th reshold (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). CONCLUS ION: 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.