A survey in Japan found that summer heat fatigue was a common issue for employees, leading to exhaustion, lack of motivation, and loss of appetite.
After Rainy Season, Heat Fatigue Season
In a survey conducted by Japanese human-resource service provider Mynavi of 20,000 full-time employees in their twenties to fifties, 38.1% of respondents said that they experienced summer heat fatigue (natsubate) in 2025. More than half (56.5%) said they had experienced it at some point in their lives. As extreme heat becomes an increasingly common phenomenon, heat fatigue is also becoming a familiar challenge for working people in summer.
In the survey, the most commonly reported symptoms of heat fatigue for last summer were “severe exhaustion” (51.0%), followed by “lack of motivation” (40.8%) and “loss of appetite” (39.3%).
Among those who experienced heat fatigue last summer, 64.4% said that it affected their work. Respondents reported lower productivity due to reduced concentration, decreased motivation caused by a loss of appetite, and a slower pace of work resulting from feeling unwell during their commute or at the workplace. The findings suggest that summer heat fatigue can have a considerable impact on daily life and job performance.
Among those who experienced heat fatigue last summer, 70.2% felt that they wanted to take time off work. However, only 38.1% of those who wanted to do so ended up actually taking time off.
It seems that even when workers are feeling unwell and have low motivation, they do not find it easy to take time off work due to heat fatigue.
Data Sources
(Translated from Japanese. Banner photo © Pixta.)