Use fans only when temperatures stay below 40°C: WHO heat wave guidance

An air conditioner and electric fans are running inside a pig barn at Sinheung Farm in Jeonui-myeon, Sejong, July 29, as livestock deaths continue to rise nationwide amid the prolonged heat wave. Yonhap

As Korea logged its highest temperature on record, with Yangsan in South Gyeongsang Province reaching 42.5 degrees Celsius, the World Health Organization (WHO) has issued guidance to help reduce health risks during extreme heat.

According to WHO on Saturday (local time), its recommendations fall into four main categories: avoiding the heat, keeping homes cool, staying cool and hydrated and protecting infants and children.

To avoid heat-related illness, WHO advises people to stay indoors whenever possible. If going outside is unavoidable, remain in the shade as much as possible. Temperatures in areas direct sunlight can be 10 to 15 degrees higher than in shaded areas. Spending two to three hours a day in a cool place and regularly checking heat wave alerts are also recommended.

Children play in the water at Cheonggye Stream in Seoul's Jongno District, Aug. 3, as sweltering heat continues across the country. Korea Times photo by Shim Hyun-chul

Keeping homes cool is another key measure. During the day, blinds or curtains should be used to block direct sunlight, while windows should be opened at night once outdoor temperatures have dropped.

WHO also recommends using electric fans only when the air temperature is below 40 degrees. At temperatures above 40 degrees, fans may circulate extremely hot air, potentially raising body temperature instead of cooling it.

When using air conditioning, WHO advises setting the temperature to 27 degrees Celsius and running a fan at the same time. This combination can make a room feel about 4 degrees cooler while reducing cooling costs by up to 70 percent.

Vendors prepare onions while working beside electric fans at Garak Market in Seoul's Songpa District, July 28, as the heat wave continues. Yonhap

The agency also stresses the importance of staying hydrated, even before feeling thirsty. Adults are encouraged to drink water regularly and consume at least 2 to 3 liters of fluids per day. Cooling the skin with a damp cloth, a spray bottle or lightweight wet clothing can also help lower body temperatures.

Special care should be taken to protect infants and young children, who are particularly vulnerable to extreme heat. Children and animals should never be left unattended in parked vehicles, where temperatures can rise rapidly. During the hottest part of the day, children should stay indoors or in the shade and avoid direct sun exposure.

WHO also warns against covering strollers with dry cloth, as doing so can trap heat and raise the temperature inside. Instead, caregivers should use a thin, damp cloth, rewetting it periodically, and use a portable fan to enhance the cooling effect.

Between 2000 and 2019, heat waves were responsible for an estimated 489,000 deaths worldwide each year on average, according to WHO. The organization warned that extreme heat is not merely an inconvenience but a serious threat to human health.

An employee inspects ice blocks ready for shipment at an ice factory in Daegu's Buk District, Aug. 3. A factory official said production has increased by 20 percent compared with last summer as the heat wave continues. Yonhap

This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by a generative AI system and edited by The Korea Times.