Changes of the Autonomic Nerve Function during a Foot Bath and How Aging Influences the Change / 日本温泉気候物理医学会雑誌

ABSTRACT

  A foot bath is one of the partial baths which soaks a foot in hot water. The effect makes the blood circulation of the part of the warmed foot better, and is effective for fatigue, edema, poor circulation, and sleep. The purpose in this study is to examine how aging influences the change of the autonomic nerve during a foot bath. The subjects were nine elderly individuals (four men, five women, average age of 73.5 ± 8.4 years old), eight young individuals (all men, average age of 25.5 ± 3.4 years old), and for a 20-minute foot bath, when I touched the lower thigh to the 41°C bath in a seated position for rest ten minutes, performed rest after a foot bath for five minutes. Tympanic temperature with a thermistor, skin blood flow with a laser Doppler flowmeter, and blood pressure and heart rate with an automatic sphygmomanometer were measured. In the younger subjects, tympanic temperature was significantly increased compared to the elderly subjects, and skin blood flow was significantly increased during the foot bath in the lower thigh with both subjects, and the younger subjects were significantly increased compared to the elderly subjects. The femor-skin blood flow significantly increased only in the young subjects. The blood pressure did not change in the young subjects during the foot bath, but the elderly subjects’ pressure dropped. The heart rate increase was shown in the young subjects; however, it was not shown in the elderly subjects. It is thought that an increase of the quantity of fat and decrease of the muscle volume due to aging, a decline in the flexibility of the blood vessel, and attenuation of the sensitivity of the receptor affect the change of these autonomic nerve functions.