Temperature Up, Motivation Down: More Than Half of Japanese Workers Affected by Summer Heat Fatigue

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

• Data from survey on workers’ summer fatigue and job performance (Japanese) by Mynavi.

(Translated from Japanese. Banner photo © Pixta.)