Abstract
Physiological changes acquired in daily life in accordance with seasonal climate variations are referred to as seasonal acclimatization. This study examined the relationship between ambient temperature and physiological changes during daily life. From May to September 2024, subjects were conducted continuous exercise load experiments in a controlled climate chamber under a constant heat environment (32°C, 50% RH), measuring physiological responses to heat stress. Additionally, subjects carried temperature loggers to measure ambient temperatures during their daily activities. The ambient temperatures experienced by the subjects showed smaller variations compared to outdoor temperatures, with some days when the observed outdoor temperatures exceeded the subjects’ ambient temperatures by more than 6°C. Therefore, it was suggested that measuring ambient temperature is useful for assessing individual heat exposure. The results of the subject experiments indicated a negative correlation between ambient temperature and the increase in mean skin temperature and sweating rate, confirming the suppression of skin temperature rise and water loss as the hot season approached. It was also shown that subjects who regularly exercise exhibited a smaller increase in core body temperature, indicating superior heat tolerance.
