著者
Issei KATO Yuta MASUDA Kei NAGASHIMA
出版者
National Institute of Occupational Safety and Health
雑誌
Industrial Health (ISSN:00198366)
巻号頁・発行日
pp.2021-0072, (Released:2021-08-20)
被引用文献数
2

Surgical masks are widely used for the prevention of respiratory infections. However, the risk of heat stroke during intense work or exercise in hot and humid environments is a concern. This study aimed to examine whether wearing surgical masks increases the risk of heat stroke during mild exercise in such environments. Twelve participants conducted treadmill exercise for 30 min at 6 km/h, with 5% slope, 35°C ambient temperature, and 65% relative humidity, while wearing or not a surgical mask (mask and control trials, respectively). Rectal temperature (Trec), ear canal temperature (Tear), and mean skin temperature (mean Tskin) were assessed. Skin temperature and humidity of the perioral area of the face (Tface and RHface) were also estimated. Thermal sensation and discomfort, sensation of humidity, fatigue, and thirst were rated using the visual analogue scale. Trec, Tear, mean Tskin, and Tface increased during the exercise, without any difference between the two trials. RHface during the exercise was greater in the mask trial. The psychological ratings increased during the exercise, without any difference between the two trials. These results suggest that wearing surgical masks does not increase the risk of heat stroke during mild exercise in moist heat.
著者
Issei KATO Yuta MASUDA Kei NAGASHIMA
出版者
National Institute of Occupational Safety and Health
雑誌
Industrial Health (ISSN:00198366)
巻号頁・発行日
vol.59, no.5, pp.325-333, 2021-08-18 (Released:2021-10-05)
被引用文献数
2

Surgical masks are widely used for the prevention of respiratory infections. However, the risk of heat stroke during intense work or exercise in hot and humid environment is a concern. This study aimed to examine whether wearing a surgical mask increases the risk of heat stroke during mild exercise in such environment. Twelve participants conducted treadmill exercise for 30 min at 6 km/h, with 5% slope, 35°C ambient temperature, and 65% relative humidity, while wearing or not a surgical mask (mask and control trials, respectively). Rectal temperature (Trec), ear canal temperature (Tear), and mean skin temperature (mean Tskin) were assessed. Skin temperature and humidity of the perioral area of the face (Tface and RHface) were also estimated. Thermal sensation and discomfort, sensation of humidity, fatigue, and thirst were rated using the visual analogue scale. Trec, Tear, mean Tskin, and Tface increased during the exercise, without any difference between the two trials. RHface during the exercise was greater in the mask trial. Hot sensation was greater in the mask trial, but no influence on fatigue and thirst was found. These results suggest that wearing a surgical mask does not increase the risk of heat stroke during mild exercise in moist heat.
著者
Yuta Masuda Issei Kato Kei Nagashima
出版者
The Japanese Society of Physical Fitness and Sports Medicine
雑誌
The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)
巻号頁・発行日
vol.10, no.5, pp.243-253, 2021-09-25 (Released:2021-09-16)
参考文献数
37

The aim of the present study was to clarify the factors affecting an increase in core body temperature during 40°C water immersion to the subclavian level. Fifteen healthy males were immersed in water for 60 min. Rectal temperature (Trec) and skin temperature (Tsk) at four skin sites were determined. Minute ventilation (VE) was measured, and metabolic rate was determined by indirect calorimetry. Skin blood flow and sweat rate at the forehead were assessed using laser-Doppler flowmetry (%LDFhead) and dew hygrometry (SRhead), respectively. Hot feeling was assessed with a visual analog scale. When Trec reached 39°C or participants reported an extremely hot feeling, the experiment was ceased. Eleven participants were unable to complete the protocol (ten participants due to Trec > 39°C; and one due to excessive hot feeling). Trec increased with immersion period. Mean Tsk was unchanged from 20 min. VE and metabolic rate increased with immersion period. %LDFhead and SRhead increased after immersion and remained unchanged from 15 and 30 min, respectively. Change in Trec from the baseline at 15, 30, and 45 min was correlated to cumulative change in metabolic rate from the baseline at 0-15, 0-30, and 0-45 min. No correlations were observed between change in Trec and cumulative changes in VE, %LDFhead, and SRhead from baseline, hot feeling, body weight and body composition. Water immersion at 40°C induced a large difference in the increase of Trec, in which metabolic responses to heat stress may be involved. The relationship between heat tolerance and change in Trec is different among individuals.