Coping with Heat Stroke Risk in School Sports in Japan

Challenge

Rising summer temperatures in Japan are increasing heat stroke risk in educational settings, especially outdoor school sports.

Solution

Schools and sports organizations are reviewing and adjusting activity schedules, monitoring heat index, and promoting awareness campaigns to help protect students from heat stroke during sports.

Overview

Japan’s annual mean temperature is rising at a rate of 1.24°C per century, with higher temperatures particularly noticeable in the summer months (JMA, 2019). This temperature rise has resulted in increased health hazards from heat stroke, including in schools and educational settings. Summer temperatures in FY2023 were the highest in northern, eastern, and western Japan since the Japan Meteorological Agency (JMA) began recording statistics in 1946, and the number of emergency medical evacuations from heat stroke reached 91,467 nationwide (MEXT).

In Japan, club activities are regarded as an educational activity. Baseball and other sports involve long hours of daily outdoor practice and strenuous exercise. The risk of heat stroke is particularly high in the National High School Baseball Championship held every August, one of the hottest months. Heat stroke countermeasures are especially relevant for athletic teams that wear heavy uniforms.

Oyama et al. (2024) showed the importance of taking measures to reduce the risk of heat stroke according to the type of club activity, time of year, region, and location of the activity.

Heat index monitoring

Officials use the Wet Bulb Globe Temperature (WBGT) – a composite temperature that measures heat stress in direct sunlight by accounting for temperature, humidity, wind speed, and solar radiation – to evaluate conditions before an activity begins. If the index exceeds the standard value, it is advised to consider suspending or reducing the time of the activity (MoE and MEXT guidelines [in Japanese]).

Rescheduling and restructuring baseball games

The Japan High School Baseball Federation introduced a two-part system for the first three days of the August series. Matches are divided into morning and evening sessions to avoid high midday temperatures.

The Federation also has been working on measures to protect players from severe heat, including shortening games from nine to seven innings. A working group has been established to study this change, with discussions were set to be finalized in December 2024, and with a new meeting to discuss other issues in high school baseball.

Education and awareness

Non-profit organizations are also promoting educational activities for players and spectators, such as the distribution of heat stroke prevention leaflets and the airing of informational videos.

Outlook

Rising temperatures from climate change increase the risk of heat stroke in educational activities, especially those that require long hours of outdoor exercise. Although schools and organizations in Japan are currently implementing various measures, flexible responses to situations and continued awareness-raising will remain necessary.

Acknowledgements

This report is based on publicly available information from the sources listed below. Acknowledgement is given to the organizations and researchers that have made this knowledge accessible. Reported by IGES, edited and updated by AP-PLAT.

Related Information

Japan Meteorological Agency (JMA) (2019): Climate Change Monitoring Report 2019

Ministry of Education, Culture, Sport, Science and Technology (MEXT) Japan: Prevention of Heat Stroke Accidents in School Educational Activities (Request) (April 30, 2024, 6-Kyo Sangaku No. 5) (in Japanese)

Ministry of the Environment (MoE) and Ministry of Education, Culture, Sport, Science and Technology (MEXT) Japan: Guideline for the Preparation of Heat Stroke Prevention Guidelines for Schools (in Japanese)

Oyama, T., Honda, Y., Fujii, M., Nakajima, K., and Hijioka, Y. (2024). Proposing adjustments to heat safety thresholds for junior high and high school sports clubs in Japan, International Journal of Biometeorology, 10.1007/s00484-024-02812-4.