暑熱環境下で剣道具を着用して行う全力ペダリング運動間の手掌アイシングが深部体温ならびに発揮パワーに及ぼす影響

抄録

Kendo athletes, who wear kendo-gu, experience an impaired ability to dissipate body heat in a hot and humid environment during the summer, increasing the risk of heat stroke. Furthermore, excessive surges in core body temperature during exercise result in reduced exercise capacity. The hairless regions of the face, palms, and soles, especially the nasal area, have arteriovenous anastomoses, which are vascular structures specialized for heat dissipation. Therefore, applying ice in these areas may efficiently mitigate the increase in core body temperature and the decrease in exercise performance in a hot and humid environment. This study examined the effects of palmar cooling on core body temperature and exerted power through full-force pedaling exercises while wearing kendo-gu in a hot and humid environment. Eight male university kendo athletes participated in experiments conducted in a climate chamber with the wet-bulb globe temperature set at 28˚C. While wearing kendo-gu, the participants performed two 4-minute intermittent bicycle pedaling exercises, comprising eight sets of 20-second full-force pedaling and 10-second rest periods, with 15-minute rest periods in between exercises. Two experimental conditions were implemented, namely, a control condition, in which the participants remained at rest in a sitting position, and an ice application condition, in which their hand was immersed in cold water to cool their palm. External auricular temperature was used as the core body temperature. The results revealed an interaction between the two conditions when the external ear temperature changes during rest periods between exercises (P < 0.01). From the sixth minute of rest, outer ear temperature was significantly lower in the ice application condition than the control condition (P < 0.05). Moreover, the rate of decline in exerted power during the two full-force pedaling exercises was significantly smaller in the ice application condition than the control condition (P < 0.05). These results suggest that even when exercising in a hot and humid environment while wearing kendo-gu, individuals may lower their core body temperature and reduce their risk of heat stroke by cooling their palms between exercises. Furthermore, this method lessened the decline in exercise performance in a hot and humid environment.