This study aims to determine the relative exercise intensity of classical Yang Tai Chi Chuan (TCC) in different ages and gender. One hundred TCC practitioners (54 men and 46 women) aged 25 to 80 years participated in this investigation. Men and women were separated into three groups: young (25-44 y/o), middle-aged (45-64 y/o) and elderly (65-80 y/o). Heart rate (HR) responses during TCC practice were measured by using electrocardiographic telemetry. An exercise test with breath-by-breath measurements of cardiorespiratory function was also performed for each subject during the incremental exercise of leg cycling. Measurements obtained during the TCC practice and exercise testing were compared to determine the exercise intensity of TCC. While performing TCC, the mean HR of men was 141 +/- 12 bpm, 132 +/- 9 bpm and 120 +/- 10 bpm in the young, middle-aged and elderly groups, respectively. Men practiced TCC with mean HR corresponding to 57.8 +/- 3.7%, 56.6 +/- 3.4% and 55.1 +/- 3.1% of heart rate reserve (HRR) in the three groups. Meanwhile, the mean HR of women was 136 +/- 10 bpm, 126 +/- 11 bpm and 115 +/- 12 bpm in the young, middle-aged and elderly groups, respectively. Women practiced TCC with mean HR corresponding to 52.7 +/- 2.8%, 51.5 +/- 2.6% and 50.3 +/- 2.9% of HRR in the three age groups. The results demonstrate that classical Yang TCC is an exercise with moderate intensity, and its exercise intensity is similar across different ages in each gender. In conclusion, TCC is an aerobic exercise and suitable for participants of different ages and gender to improve their functional capacity.