EFFECTS OF EXERCISE ON COLD-INDUCED VASODILATION IN YOUNG WOMEN / 体力科学

ABSTRACT

The effects of exercise on cold-induced vasodilation (CIVD) as an index of local cold tolerance caused by a shift in the core body temperature in the follicular and luteal phases to a lower level were evaluated in athletes and non-athletes. The subjects were healthy female students with a normal menstrual cycle, who consisted of 15 athletes and 9 non-athletes. The percent body fat was lower, and the maximal oxygen intake was significantly higher in the athletes than in the non-athletes. The difference in the basal body temperature between the follicular and luteal phases differed significantly (P<0.01) between the athletes (0.53±0.221) and the non-athletes (0.88± 0.26t) . CIVD was measured once in the late follicular phase and once in the midluteal phase in the spring of 2002. Finger skin temperature before ice water immersion did not differ between the follicular and luteal phases in the athletes or non-athletes. The mean finger skin temperature was higher in the luteal phase in both the athletes and non-athletes. Similarly, the temperature of the first rise was higher, and the time of temperature rise was shorter, in the luteal phase. The resistance index was 11.47±2.36 in the follicular phase and 13.40±1.45 in the luteal phase in the athletes, and 10.44±3.21 and 11.89±2.09, respectively, in the non-athletes. It was significantly higher in the luteal phase in the athletes but showed no significant difference in the non-athletes. In addition, it was significantly higher in the athletes than in the non-athletes in the luteal phase, but no difference was observed between the two groups in the follicular phase. These results suggest that the finger skin temperature during ice water immersion was maintained at a higher level in the athletes than in the non-athletes despite the greater reductions in the basal body temperature in the luteal phases in the athletes ; this is because of suppression of cutaneous vasoconstriction and an increase in collateral blood flow. Moreover, cutaneous vasodilation induced by the axon reflex of sensory nerves, release of histamine substances, reduction of vascular sensitivity to catecholamines, or release of vasodilators is considered to be a mechanism of the higher resistance index in the athletes.