METHODS: Twenty Tai Chi practitioners and 20 normal controls were included in this study. The stationary state spectral heart rate variability (HRV) measures between Tai Chi practitioners and normal controls, and the sequential changes in HRV measures after classical Yang\'s Tai Chi were compared. RESULTS: The total power, very low-frequency power, low-frequency power, normalized low-frequency power, and low-/high-frequency power ratios in Tai Chi practitioners were all significantly higher than those of normal controls, whereas the heart rate and systolic and diastolic blood pressures were not different between these two groups of subjects. After Tai Chi, the normalized high-frequency power increased significantly from 23 to 28 30 min after Tai Chi and to 31 60 min after Tai Chi. In contrast, the low-/high-frequency power ratio decreased significantly from 3 before Tai Chi to 2 30 min after Tai Chi and to 2 60 min after Tai Chi. The heart rate, systolic blood pressure, diastolic blood pressure, mean arterial blood pressure, and pulse pressure also decreased sequentially after Tai Chi. The short-term effect of Tai Chi was to enhance the vagal modulation and tilt the sympathovagal balance toward deceased sympathetic modulation in older persons. Tai Chi might be good health-promoting calisthenics for older persons.

The effect of Tai Chi Chuan on the autonomic nervous modulation in older persons