What to know about Korea's life-threatening heat wave and how to stay safe

Visitors cool off at a splash pad in a park in Dong District, Daegu, Monday, as heat alerts remain in effect across the city. Yonhap

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The end of the monsoon season this week marked the beginning of a severe heat wave across Korea, with temperatures reaching life-threatening levels.

As of Monday, Seoul had experienced three consecutive tropical nights, during which temperatures remained above 25 degrees Celsius from 6 p.m. to 9 a.m. the following day. Feels-like temperatures have hovered around 38 to 39 degrees Celsius for days, placing children, older adults and outdoor workers at heightened risk of heat-related illness and death.

Weather patterns over the past decade suggest that, as the climate changes, extreme heat waves and mass outbreaks of heat-related illness are becoming the new normal for Korean summers. For those living in Korea, here are some tips for protecting your health and that of those around you.

Proper care for heat illness patients

Heat-related illness should not be taken lightly or managed alone. The U.S. Occupational Safety and Health Administration, a Labor Department agency that oversees workplace safety, advises that anyone showing symptoms of heat-related illness be cooled immediately with ice and taken to an emergency room, and most importantly, should not be left alone.

Heat-related illness largely falls into two categories: life-threatening heatstroke and heat exhaustion, which is usually treatable. Either condition requires immediate hospitalization and professional medical assistance, rather than self-diagnosis by the patient.

Distinguishing between heatstroke and heat exhaustion

The causes, symptoms and required responses for heatstroke and heat exhaustion differ, making it important to distinguish between them. Heatstroke occurs when the body’s temperature-regulation system fails and its temperature soars above 40 degrees Celsius. Patients often struggle to remain conscious or may fall into a coma or experience seizures.

Heatstroke is a life-threatening medical emergency, making immediate transport to an emergency room essential to lower the patient’s body temperature. Other symptoms include unstable breathing, a rapid pulse, vomiting or no sweating at all.

Heat exhaustion, meanwhile, occurs when the body loses too much water and sodium through excessive sweating. Symptoms include dizziness, headache and nausea. Unlike heatstroke, it does not generally cause a high body temperature, confusion, loss of consciousness or seizures. Patients can recover by resting in a cool place and replenishing fluids and electrolytes, but it is still important to seek medical attention to ensure their safety.

Korea’s heat warning system

The Korea Meteorological Administration (KMA) issues three levels of heat alerts based on forecast temperatures. A heat advisory is issued when the daily maximum feels-like temperature is expected to reach 33 degrees Celsius or higher for at least two consecutive days. A heat warning is issued when it is expected to reach 35 degrees or higher for the same period.

The highest-level alert, a severe heat warning, is issued when the daily maximum feels-like temperature is forecast to reach 38 degrees or higher, or the daily high is expected to reach 39 degrees or higher, for at least one day.

The KMA advises people to avoid prolonged outdoor activity between noon and 6 p.m. and drink plenty of fluids when a heat advisory is issued. When a heat warning is in effect, both outdoor work and nonessential outings should be kept to a minimum. Assuming that you will be fine simply because you are healthy or have endured similar heat before can put you at serious risk.

When a severe heat warning is issued, all outdoor activity should be suspended. People should move to a safe, air-conditioned place, such as their home or a designated cooling center, where they can protect themselves from the heat and avoid heat-related illness.

Older adults, children and others particularly vulnerable to heat should avoid outdoor activity whenever possible during hot weather, even when no official heat alert is in effect. Drinking plenty of fluids and using air conditioners and fans as needed at home or at work can be vital to protecting their health and lives.

People visit Banpo Hangang Park in Seoul on Wednesday, as heat warnings are in effect across the city’s southeastern, northeastern and southwestern areas. Yonhap

Older adults and rural residents most vulnerable to heat-related illness

Statistics from the Korea Disease Control and Prevention Agency (KDCA) show that people aged 65 and older are the group most vulnerable to heat waves. While they account for 21 percent of the total population, they made up 29.5 percent of all patients with heat-related illnesses, at 384. Those with underlying conditions such as high blood pressure or diabetes, or a history of cardiovascular disease such as heart attacks or angina, should take particular care by avoiding outings whenever possible and staying in air-conditioned places.

By location, workplaces recorded the highest number of cases at 346, accounting for 26.6 percent of all patients. They were followed by rice paddies and fields, with 203 patients, or 15.6 percent, and roadsides, which accounted for 13 percent. The breakdown suggests that many people develop heat-related illnesses while working, particularly at outdoor worksites in both urban and rural areas.

Considering that agricultural workers account for around 5 percent of the total population, the fact that 15.6 percent of patients were reported in rice paddies and fields is particularly significant. One possible explanation is that rural areas lack shade structures that offer protection from the sun, as well as working conditions that allow workers to adjust whether, when and how intensively they work according to the temperature. The fact that a majority of workers in the sector, 51.3 percent to be precise, are aged 65 or older is also a contributing factor.

Multiple heat-related deaths reported in fields amid extreme heat

According to the KDCA, more than 1,399 people visited emergency rooms with heat-related illnesses between May 1 and July 26. Eight of them died, with rural areas accounting for more than half of the deaths.

A closer look at some of the fatal cases documented in official data and reports shows the risks posed by the extreme heat.

On July 22, a 97-year-old woman collapsed while working inside a greenhouse in Goseong County, South Gyeongsang Province. She was taken to an emergency room, but later died. A heat advisory was in effect in the area that day, with the maximum feels-like temperature reaching 32.7 degrees Celsius.

On July 23, a 93-year-old man who had left his home in Sacheon, South Gyeongsang Province, was found unconscious in a nearby field and died two days later. A heat advisory was in effect on the day he was found, when the temperature peaked at 33.9 degrees and the maximum feels-like temperature reached 34 degrees. His cause of death was recorded as heat-related illness and multiple organ failure.

A Thai agricultural worker in his 30s also died after collapsing while returning to his accommodation from a field in Haenam County, South Jeolla Province, on Saturday. He had reportedly complained of dizziness before losing consciousness. A heat warning was in effect in Haenam that day, with the daytime high reaching 33.7 degrees Celsius.

On Sunday, a 100-year-old woman died from a heat-related illness while working in a field in Wanju County, North Jeolla Province, as the daytime high reached 34.7 degrees. Her body temperature was 42.2 degrees when she was found.

This article from Kormedi.com, Korea’s top health care and medical portal, is translated by a generative AI system and edited by The Korea Times.