Effects of wearing a surgical mask on thermoregulation and respiratory parameters during exercise with hyperthermia-induced hyperventilation

Abstract

The increase in core temperature during exercise in a hot environment causes hyperventilation (hyperthermia-induced hyperventilation), which decreases the partial pressure of arterial blood carbon dioxide. However, the effects on the body of wearing a surgical mask during exercise that would cause hyperthermia-induced hyperventilation have not been clarified. Therefore, we investigated such effects. Ten healthy men participated in the study. A 44-minute steadystate load cycling exercise (55% of peak oxygen uptake) was performed under hot environmental conditions (30℃, 70% relative humidity). Two experimental conditions were set: exercising with surgical face mask (MASK) and without a surgical face mask (CON). The experiment was conducted as a randomized crossover design. Body temperatures, respiratory gas exchange, and subjective indices were measured during exercise. In terms of physiological indices, respiratory rate only revealed a main effect and was significantly lower in the MASK than in CON at 44 min of exercise (CON 41.0±19.2 breaths/min, MASK 35.6±11.2 breaths/min p=0.029). No significant differences were observed between conditions in other physiological parameters. As for the subjective indices, dyspnea showed a condition × time interaction (p=0.016), which was significantly higher in the MASK starting at 5 minutes through the end (CON 4.5±3.5 and MASK 8.5±2.1 at the end of exercise p=0.016). No significant differences were observed in other subjective measures. In conclusion, wearing a surgical face mask during moderate-intensity prolonged exercise under hot environmental conditions significantly worsened dyspnea, but no significant differences were observed in other physiological indices or subjective indices.

Effects of running with surgical masks on cardiopulmonary function in healthy male university students

“…However, no discernible difference was observed when compared with the Mask-off condition. This lack of difference is likely because sweating rather than respiration primarily influences evaporative heat loss during exercise, and wearing a surgical mask does not significantly impact thermoregulatory responses 15 ) . Wearing a mask during exercise has been suggested as a factor that could increase blood CO 2 levels because of the rebreathing of residual exhaled air within the mask, potentially exacerbating dyspnea 16 ) .…”