Heat exhaustion and heatstroke have similar warning signs, but heatstroke can be life-threatening and should be addressed immediately.
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Any person with exposure to extreme heat for a prolonged time is at risk of developing heat exhaustion and heatstroke.[1] Extreme heat kills around 1,000 people in the United States every year, according to the Centers for Disease Control and Prevention (CDC), and thousands more suffer from nonfatal heat-related illness, or hyperthermia.[2]
Summer days are already hot, and they’re getting hotter. The National Centers for Environmental Information confirmed that 2023 was the hottest year on record, with the 10 warmest years in 174 years of record-keeping all occurring between 2014 and 2023.[3] Hotter days, and more of them, mean it’s important to know about heat-related illnesses and their warning signs.
How Are Heatstroke and Heat Exhaustion Different?
Despite their similarities, heatstroke and heat exhaustion have different effects on the body. Heat exhaustion relates to dehydration and subsequent struggle of the heart to pump blood throughout the body. Heatstroke occurs when a person’s body temperature gets so dangerously high that it begins overheating the tissues and organs, says William Roberts, MD, a professor of family medicine and community health at the University of Minnesota in Minneapolis.
People can usually treat heat exhaustion with cold water, cool air, and rest. Heatstroke is an emergency medical condition that requires immediate care.
Although heatstroke might appear to progress from heat exhaustion, Dr. Roberts says that a person may not show signs of heat exhaustion before experiencing heatstroke. “You can go right there without the intervening step,” he says. In any instance, swift attention is key to avoiding complications of both heatstroke and heat exhaustion.
Research has shown that people who experience heat-related illnesses may be at a greater risk for eventually developing some cardiovascular diseases. According to a small study published in February 2019 in the journal PLoS One, people who had experienced heat-related illness previously were associated with a greater risk of having a heart attack, stroke, and chronic kidney disease.[4]
