Prof. Shōji Yokobori of Nippon Medical University is urging evacuees and recovery workers in Kumamoto Prefecture to prioritize hydration to prevent heat-stroke.
The warning comes as a severe summer heat wave persists three days after a major earthquake. This weather event, linked to a predicted “Super-El Niño,” creates a dangerous environment for people living in temporary shelters or performing reconstruction work.
Yokobori, an emergency-medicine professor, said that some people in evacuation shelters may avoid drinking water because they do not want to use the restroom. He said that individuals must stay hydrated before they even feel thirsty to avoid medical emergencies.
To maintain health during the heat wave, Yokobori recommended a specific intake schedule. He said that people should drink roughly half a cup of water, or approximately 120 ml [1], every hour. This amount is intended to replenish fluids lost through sweat and keep the throat moist.
"In evacuation centers, some people may hold back on using the toilet and avoid taking fluids, but I want them to take fluids frequently when they feel thirsty," Yokobori said. "For example, once an hour, even half a cup is fine; I want them to take fluids in a way that moistens the throat and replenishes what was lost through sweat."
The professor said that these measures are critical for both the displaced population and the teams working on the ground to restore infrastructure. The combination of physical exertion and extreme temperatures increases the risk of heat-related illness significantly.
“"I want them to take fluids frequently when they feel thirsty,"”
The intersection of a natural disaster and an extreme climate event creates a compounding crisis. In evacuation settings, psychological barriers—such as the reluctance to use shared restroom facilities—can lead to dehydration, making a vulnerable population more susceptible to heat-stroke during a Super-El Niño event.
