"Even Homes Are at Risk During Heatwaves"... Indoor Heat-Related Illnesses Double When Temperatures Exceed 38 Degrees

Sharp Increase in Indoor Heat-Related Illnesses at Temperatures Above 38 Degrees
Government Urges Extra Caution for Seniors and Those With Chronic Illnesses

It has been found that even indoor environments can be dangerous during extreme heat, when temperatures exceed 38 degrees Celsius. This means that staying at home is not necessarily safe if proper cooling is not available, even if people refrain from going outside.

On August 1, the Ministry of the Interior and Safety made public the results of an analysis by the National Disaster Management Research Institute, which utilized data from the Korea Disease Control and Prevention Agency and the Korea Meteorological Administration. The ministry urged the public to actively use air conditioners and other cooling devices whenever a heatwave warning is in effect, and recommended that people visit designated cooling centers if cooling at home is not possible.

The institute analyzed heat-related illness cases from 2011 to 2025 and found that on days with a maximum temperature below 38 degrees, 6.2% (1,441 cases) of patients developed heat-related illnesses at home. However, on days when the maximum temperature reached 38 degrees or higher, the proportion rose to 12.8% (784 cases), showing a tendency to nearly double.

On the 31st of last month, when the midday temperature in Seoul rose to 34 degrees Celsius, citizens were enjoying water play at the fountain in Gwanghwamun Square, Jongno-gu, Seoul. Photo by Yonhap News Agency

Usually, most heat-related illnesses in Korea occur outdoors, such as in outdoor workplaces, fields, or on streets. Among the 1,701 reported cases of heat-related illnesses from May 15 to July 30 this year, the largest proportion (26.6%) happened at outdoor workplaces, followed by fields, streets, and parks. The figure for home settings was 5.9%. However, the research indicates that during periods of intense heatwaves, the number of patients indoors can also increase significantly.

Similar trends have been observed overseas. France recorded its hottest June on record this summer, with excess deaths between June 17 and July 2 exceeding the annual average by more than 36%. In particular, during the most severe heatwave from June 22 to 28, the number of deaths at home surged by 91% compared to the previous week. The French government is expanding direct support by offering assistance with the use of cooling facilities and deploying postal workers and neighbors to check on residents living alone and other vulnerable groups.

Japan also experienced a heatwave in July, with maximum temperatures surpassing 40 degrees for five consecutive days in some regions. During this period, 18,591 people were transported by ambulance for heat-related illnesses in one week, with homes being the most common location accounting for 40.9% of cases. Among 35 heat-related deaths investigated in Tokyo, 26 people either had no air conditioner installed or did not use one even if it was available. Consequently, the Japanese government is recommending the appropriate use of cooling devices even at night and is operating cooling centers across 1,255 local municipalities nationwide.

The government emphasized that people most vulnerable to the heat—such as seniors, those with chronic illnesses, people with disabilities, pregnant women, and children—should make active use of cooling devices and stay well-hydrated. Minister of the Interior and Safety, Ho Joong Yoon, stated, "As heatwaves worsen, there is a tendency for heat-related illnesses occurring at home to increase," and urged, "If cooling is difficult at home, please actively use nearby cooling centers and have family members and neighbors regularly check on the health status of vulnerable individuals."

This content was produced with the assistance of AI translation services.