[Click! Health] Endless Heat... Beware of 'On-Yeol Disease'

Although summer is coming to an end, the temperature remains high, continuing the sweltering midsummer weather. With the ongoing heatwave, the risk of heat-related illnesses remains high. We explored ways to prevent heat-related illnesses with Professor Son Ki-young from the Department of Family Medicine at Seoul Asan Medical Center.

A farmer is wiping sweat while working in the field under the scorching sun in an agricultural field. [Image source=Yonhap News]

Heat-related illnesses refer to acute conditions caused by prolonged exposure to hot environments. They range from relatively mild heat exhaustion to potentially fatal heatstroke. According to the Korea Disease Control and Prevention Agency’s heat-related illness emergency room surveillance system, 674 cases were reported nationwide from May 20 to July 22. Among these, the majority, 368 cases (54.5%), occurred during daytime hours (12 PM to 5 PM). By age group, those aged 65 and older accounted for 30% of all patients. Regarding location, outdoor patients working in fields, farms, or by the roadside numbered 559 (82.9%), overwhelmingly more than indoor patients. As the heat intensifies, elderly people, children, and those with chronic illnesses who have difficulty coping on their own should be cautious, as they may be exposed to high temperatures without protection during outdoor activities.

Looking at the types, if exposed to heat for a long time without adequate hydration and electrolyte replenishment, heat exhaustion (heat syncope) can occur. Symptoms may include dizziness, fatigue, nausea, weakness, fever, sweating, flushing, tachycardia, vomiting, and confusion. In such cases, rest in a cool place and replenishment of water and electrolytes are necessary. If a high fever above 40 degrees Celsius or changes in consciousness are observed, active treatment such as rapid cooling therapy may be required.

If someone has been exposed to heat for a long time but is not sweating and shows symptoms such as nausea, vomiting, or altered consciousness, heatstroke should be suspected. It occurs when elderly people, heart patients, dementia patients, alcoholics, or psychiatric patients are exposed to hot and humid environments for extended periods. Although symptoms may appear similar to heat exhaustion, heatstroke is characterized by the absence of sweating, severe nausea and vomiting, and altered consciousness. Core body temperature can exceed 40 degrees Celsius. The patient should be immediately moved to the shade, loosened from clothing, wiped with cool wet towels, and 119 emergency services should be called promptly for hospital transfer. Giving the patient cold water to drink may help lower body temperature, but if the patient is unconscious, it could cause choking, so caution is necessary.

When exercising for a long time in the heat, sweating increases more than usual, making muscle cramps known as heat cramps more likely to occur. The exact cause is not clearly known, but it is believed to be related to electrolyte imbalance. When heat cramps appear, muscles should be stretched in a cool shaded area. It is important to avoid intense exercise for at least a few hours while resting, and replenishing electrolytes by drinking electrolyte-containing fluids aids recovery. If electrolyte drinks are unavailable, adding one or two teaspoons of salt to 1 liter of water can be used as a substitute.

Prevention of Heat-Related Illnesses
[Image Source=Seoul Asan Medical Center]

When elderly people or children are exposed to sweltering heat, heat syncope may occur as their bodies fail to adapt to the external temperature. This happens because blood volume decreases and peripheral blood vessels dilate. Simple heat syncope usually recovers easily with rest. Find a cool shaded area, monitor breathing and pulse, lower the head, and replenish fluids.

Prolonged exposure to strong sunlight can cause the skin to become red and painful. In severe cases, blisters may form, and the face and limbs may swell and feel hot. This is called sunburn. To prevent sunburn, avoid going outdoors between 11 AM and 3 PM on clear summer days without clouds, as this is when direct sunlight is strongest. At other times, cover exposed skin with thin outerwear or apply sunscreen thoroughly 30 minutes before going outside. If symptoms occur, apply cold compresses, and if pain is severe, it can be managed with analgesic anti-inflammatory medication.