Heat Illnesses Surge Amid Heatwave... Elevated Kidney Disease Risk for the Elderly

Acute Kidney Injury Cases Peak in July and August During Summer
Adequate Hydration and Indoor Temperature Control Are Essential
'Home' Also Poses Hidden Risks for Heat-Related Illnesses During Heatwaves

With record-breaking heatwaves pushing temperatures above 38 degrees Celsius for consecutive days, there are growing concerns about heat illnesses and dehydration-induced kidney disorders. Medical professionals emphasize that elderly individuals, whose ability to sense thirst is diminished, often fail to realize when they are dehydrated—greatly increasing the risk of acute kidney injury (acute renal failure).

According to the Korea Disease Control and Prevention Agency (KDCA) on August 1, a total of 72 people visited emergency rooms across more than 500 locations nationwide due to heat-related illnesses on the previous day. Between May 15 and July 31 of this year, there were 1,781 patients (including 13 fatalities) registered in the emergency room heat illness surveillance system. As of July 30, Seoul had slightly more cases, but within a single day, the numbers shifted: Gyeongnam reported 161 patients (with 3 deaths) and Seoul 158 patients (with 2 deaths).

Heat-related health risks do not occur outdoors only. According to an analysis by the National Disaster Management Research Institute at the Ministry of the Interior and Safety, which examined data from the KDCA and the Korea Meteorological Administration from 2011 to 2025, about 6% of all heat illnesses generally occurred at home. However, during heatwaves when the daily maximum temperature was at least 38 degrees Celsius, this proportion roughly doubled to 12%. Spending extended periods indoors without adequate cooling can result in severe dehydration, making it clear that staying at home is not necessarily safe.

In Japan, 40.9% of heat illness-related ambulance dispatches during the peak week of last month's heatwave took place at home. In France, a recent increase in heat-related deaths at home during heatwaves has prompted authorities to step up home-centered measures, such as checking on elderly individuals living alone and providing support for air conditioning facilities.

The ongoing extreme heat also necessitates heightened attention to acute kidney injury. Last year, July saw the highest number of patients seeking medical care for acute kidney injury, with 9,427 cases, while in August there were 9,119 cases. Excessive sweating during the summer without adequate replenishment of water and electrolytes can lead to dehydration. As blood flow to the kidneys decreases, the risk of acute kidney injury rises. Because the kidneys filter waste from the blood, their function can rapidly deteriorate if blood supply declines.

On the 29th of last month, when a heatwave warning was issued in the Seoul area, shimmering heat waves rose above the scorching hot asphalt on Yeouidaro, Yeongdeungpo-gu, Seoul. Photo by Jin-hyeong Kang

This risk is especially pronounced for the elderly, who experience a decrease in body water and a dulled sense of thirst due to aging, making dehydration more likely. Their ability to maintain kidney function in dehydrated states is also lower than that of younger individuals, so even mild dehydration can impact their health. Additionally, those with underlying conditions such as diabetes, hypertension, or heart failure may experience kidney stress from even mild dehydration.

Experts advise against waiting until you feel thirsty, recommending instead the habit of drinking small amounts of water regularly throughout the day. Generally, a daily intake of 1.5 to 2 liters is recommended for healthy individuals in stable condition. In contrast, patients with chronic kidney disease or those undergoing dialysis should consult their healthcare providers, as excessive fluid intake may lead to edema and other complications. They should adjust their fluid consumption according to their individual medical status under professional guidance.

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