The effect of exercise intensity on calf volume and thermoregulatory responses during upper body exercise

Abstract

During upper body exercise the vascular adaptations of the leg have been reported to play an important thermoregulatory role. This study examined the effect of exercise intensity on thermoregulation during upper body exercise. Nine healthy male participants undertook an incremental exercise test on an arm crank ergometer to determine peak power (Wpeak). The participants performed four experimental trials involving 5 minutes of arm exercise at either 45, 60, 75, or 90% Wpeak (70 rev.min-1) followed by 30 minutes of passive recovery. Aural and skin temperatures, upper arm and calf heat fl ow were recorded. Calf volume was measured during exercise using plethysmography. During exercise at 45, 60, 75 and 90% Wpeak calf volume decreased (P<0.05) by -0.7±0.8, -1.4±0.9, -1.2±0.6 and -1.6±0.7% respectively. Differences were observed between 45 and 60% Wpeak, and 45 and 90% Wpeak (P<0.05). The results of this study suggest a redistribution of blood from the relatively inactive lower body during arm exercise of intensities up to 60%Wpeak after which point calf volume does not significantly decrease further. Therefore, the redistribution of blood from the inactive lower body does not produce a similar intensity dependent response to visceral blood fl ow during lower body exercise. ABSTRACT FROM AUTHOR