Heat-Related Deaths During School-Supervised Activities in Japan: A 19-Year Nationwide Study Using the Japan Sport...

Children and adolescents in school sports are vulnerable to exertional heat illness, but detailed information on fatal events under school supervision in Japan is limited. This study aimed to characterize the circumstances of fatal heat-related illness in this setting.

We conducted a nationwide retrospective observational study using the Japan Sport Council School Accident Search Database. We included deaths among preschool to high school students between April 2005 and March 2024 attributed to heat illness during school-supervised activities. Demographics, school type, setting, activity at collapse, and first aid at the scene were abstracted.

Of 1151 school-related deaths, 27 (2.3%) were attributed to heat illness. Median age was 16 years (interquartile range: 15-17); 25 students (93%) were male, and 19 (70%) were high school students. First-year high school students represented the largest subgroup (n = 8, 30%). Nineteen deaths (70%) occurred outdoors and eight (30%) indoors, most commonly in gymnasiums. Extracurricular sports accounted for 21 deaths (78%), including judo, soccer/futsal, rugby, and baseball. Running preceded collapse in 13 cases (48%). Witnesses were present in 21 cases (78%), yet cooling was documented in 9 cases (33%), while whether cooling was performed could not be determined in 12 cases (44%).

Fatal heat-related illness in Japanese schools predominantly affects first-year high school students engaged in strenuous conditioning during extracurricular sports and occurs in outdoor and indoor environments. Limited documentation of cooling despite witnesses indicates an urgent need to strengthen school-based prevention and emergency response systems, including preparedness for rapid on-site cooling.