Signs and Symptoms of Heat Stroke You Need to Know, According to Experts

The good news is that your body gives you *many* warning signs before you have a full-blown heat stroke.

We've all said it jokingly on a muggy summer day: "I'm going to have a heat stroke." But the truth is, heat stroke—and heat-related illnesses in general—can be a potentially dangerous part of spending time outside in the summer.

Heat stroke is a heat-related illness that occurs when the body can no longer regulate its temperature, according to the CDC—that means the body temperature rises rapidly, its sweating mechanism fails, and the body is ultimately unable to cool itself down. "I think of heat stroke as [an] extreme reaction to being exposed to very high temperatures," Jazmine Sutton-Oliver, MD, who works in hospital medicine at the Cleveland Clinic, tells Health. Of all heat-related illnesses, which occur on a spectrum, heat stroke is on the more dangerous and severe end. "Heat stroke is the end result on a spectrum that starts as heat exposure," says Eric Goldberg, MD, an internal medicine physician at NYU Langone Health. Some less severe heat-related illnesses include heat exhaustion and heat cramps—both of which, if left untreated, can progress to heat stroke.

When experiencing heat stroke, the body's temperature can rise to 106 degrees Fahrenheit or higher in as little as 10-15 minutes. But sometimes, according to Dr. Sutton-Oliver, it can take days of heat exposure for a person to have heat stroke (think: if you're on a long camping trip).

Due to its severity, heat stroke can cause death or permanent disability if emergency treatment isn't given at the onset of symptoms—and those symptoms progress quickly. "Usually symptoms start very mild, [then the illness] progresses," says Dr. Sutton-Oliver. "The progression is, essentially, determined by how long you're exposed to the heat." According to the CDC, the symptoms of heat stroke include:

  • Confusion, slurred speech, altered mental status
  • Hot, dry skin or profuse sweating
  • Loss of consciousness (coma)
  • Seizures
  • Very high body temperature

But remember: Heat stroke is the most severe heat-related illness, so the warning signs of other, lesser heat-related illnesses are important here as well. Those include heat exhaustion, the symptoms of which include nausea, headache, irritability, thirst, dizziness, and decreased urine output; heat cramps, which are essentially painful muscle spasms in the abdomen, arms, or legs; and heat rash, a skin irritation caused by excessive sweating and exposure to hot weather, per the CDC.

If you're around someone who seems to be experiencing heat stroke, it's important to call for emergency medical care immediately. While you wait for an ambulance to arrive, Dr. Sutton-Oliver advises to look for shade. "Try to bring down the body temperature as quickly as possible," she says. That means placing cold, wet cloths or ice to the person's head, neck, armpits, and groin; and circulating air around the ill person to speed cooling. In a hospital setting, Dr. Sutton-Oliver says doctors will treat heat stroke patients with an IV and cold compresses to bring the temperature down safely.

The good news: heat stroke is completely avoidable—but it takes being aware of your surroundings and listening to your body. When you're outside during the summer, remember to keep track of how long you've been in the sun, wear light-colored and loose clothing, drink ample amounts of water or sports drinks (especially if you're working out), and take multiple shaded or inside breaks throughout the day.

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