Physiologic correlates of t'ai chi chuan.

BACKGROUND: T'ai chi chuan, the ancient Chinese martial art, is practiced by millions of people worldwide and is an activity of moderate intensity that involves slow, circular movements. Evidence of substantial health benefits of t'ai chi chuan is emerging, however, the physiologic mechanisms are not well-understood. T'ai chi chuan masters routinely report sensing qi or internal energy flow, particularly in the hands. The purpose of this case study was to determine whether physiologic responses normally associated with thermoregulation are activated during a basic t'ai chi chuan exercise.
METHODS: Trials consisted of three focus periods and one withdraw period (during which the subject withdrew internal energy in the hands), each followed by a rest period. Measurements included infrared-thermography (IR), thermocoupled temperature measures, and laser Doppler flowmetry.
RESULTS: Substantial increases in local palmar and face surface temperatures were observed with IR thermography during focus periods and substantial decreases were observed during the withdraw period. Fingertip surface baseline temperatures were 31.1°C for one trial, increased by 1.8°C during the focus period, and then decreased by 4.9°C during the withdraw period. A twofold increase in blood flow through fingertip regions paralleled changes in fingertip surface temperatures during focus periods.
CONCLUSIONS: Changes in regional blood flow and surface temperatures closely paralleled onsets of focus, rest, and withdraw periods and appear to be volitional activations of known vasomotor mechanisms underlying non-hairy skin regions such as the hands and face. Changes in blood flow through these vascular structures are generally autonomic thermoregulatory responses, not normally under voluntary control, but may also represent a relaxation response.