5th IOC World Congress on Sport Sciences 1999

5th IOC World Congress on Sport Sciences
with the Annual Conference of Science and Medicine in Sport 1999

Sydney 31 October -5 November 1999

Influence of Tai Chi Chuan on autonomic control of heart rate

T. Kuo*¹, G. Huang¹, J. Chen¹, C. Yang², S. Chang³ & C. Lee³
¹Department of Pharmacology, National Yang-Ming University, Taipei
²Department of Physiology, Tzu Chi College of Medicine and Humanities, Hualien
³Subcommittee of Sport Medicine, Chinese Taipei Olympic Committee

The function of the autonomic nervous system (ANS) is the main determinant of heart rate variability (HRV), which tends to decline with age. Tai Chi Chuan is a traditional Chinese shadow boxing that has been known as a feat of arms promoting health. The purpose of this study was to measure and compare the ANS function between the elderly Tai Chi Chuan exercisers (TA) and non-exercisers of similar age group from the general population (GE) [1].

The study group comprised 14 elderly Tai Chi Chuan exercisers aged 59-77 years, with a mean age (± SD) of 67.7 ± 5.4 years. They have practiced Tai Chi Chuan at least 1 hour per day, 3 times per week for 3.5-15 years. A 5-min precordial resting ECGs was performed on each subject at daytime in the supine position. Frequency-domain analysis was performed to stratify stationary RR intervals into variance, high frequency power (HF, 0.15 to 0.40Hz) and normalized low-frequency power (LF%, 0.04 to 0.15Hz). Natural logarithm transform (Ln) was applied to variance and HF to correct the skewness.

The comparison of HRV relevant parameters (RR interval, variance, HF and LF%) on groups TA and GE is listed below:

	RR interval (ms)	Ln(variance) [Ln(ms²)]	Ln(HF) [Ln(ms²)]	LF% (nu)
TA (67.7± 5.4years)	939± 28	6.8± 0.2	4.4± 0.3	60± 6
GE (65 years)	815± 8	6.4± 0.1	3.9± 0.1	47± 2
a	P<0.05	P<0.05	P<0.05	P<0.05

TA group had significantly higher RR interval, variance, HF and LF% than did the GE group.

The study indicates that Tai Chi Chuan exercisers have better control of vagal and sympathetic functions over the elderly from the general population. Tai Chi Chuan exercise, an endurance exercise that emphasizes slow and deep breathing, may have effects on the prevention of degrading of the ANS function.

References

Kuo Terry B-J, Lin T, Yang Cheryl C-H, Li C-L, Chen C-F, Chou P. (1999) Effect of aging on gender differences in the neural control of HR. Am J Physiol (Revised).