Summer 2025 is already breaking heat records across the US, with temperatures climbing higher earlier than expected. If you’re spending time outdoors, whether for work or recreation, it’s critical to know the risks of heat-related illness. Heatstroke, the most dangerous of them, can set in quickly and become life-threatening without warning.
It doesn’t just happen to athletes or people doing intense physical activity. Classic heatstroke can occur simply by being in a hot environment for too long. According to the U.S. Department of Labor, people who work outside are especially vulnerable in the first few days of exposure, because the body needs time to adapt to rising temperatures. As the heat intensifies this summer, understanding how to spot and respond to heatstroke could be the most important safety step you take.
In addition to workers, heatstroke is especially common among the elderly, very young children, including babies, and in times “when we see these heat waves that go on for several days,” Dr. Korin Hudson, an emergency room physician with MedStar Health, told CNET last year.
People with certain medical conditions and those taking certain medications or drugs, including alcohol, may also have a higher risk of heatstroke.
Here’s what to know if you or someone near you starts experiencing symptoms of heatstroke.
Heatstroke symptoms
Sometimes, heatstroke can start with symptoms of heat exhaustion, which isn’t quite as serious as heatstroke but still requires someone to cool down as quickly as possible. If left untreated, heat exhaustion can progress to heatstroke, which is a medical emergency. If your symptoms worsen, last more than one hour or you start vomiting, call 911.
Symptoms of heatstroke, according to the Mayo Clinic and the US Centers for Disease Control and Prevention, include:
- Altered mental state, including confusion, agitation and slurred speech (this may also result in “odd” behavior)
- Headache
- Hot, flushed, usually dry skin (or, alternatively, heavy sweating — if brought on by exercise, heatstroke may include moist skin)
- Loss of consciousness
- Racing heartbeat
- Rapid breathing
- Seizures
- Very high body temperature
- Vomiting
Keeping hydrated by drinking enough water, both before you head outdoors and while you’re out in the heat, is an important step to warding off heat illness.
1. Call 911
Having heatstroke is a medical emergency that requires professional care.
If there’s more than one person around to aid the person suffering heatstroke, Hudson advised that one person call 911 while the other helps the person through the steps below.
2. Get to a cooler area immediately
If you’re around someone who has heatstroke, move them to a cooler area, such as a nearby air-conditioned room or into the shade.
Either way, “try to move them out of the heat as quickly as possible,” Hudson said. The goal is to cool down the body’s core temperature.
3. Take off excess clothing
Removing long-sleeve shirts, pants or other clothing will help a person cool down faster. Hudson said the goal is to reach “evaporative cooling,” and clothing can prevent evaporation.
(For people who choose to run in layers to “sweat off weight,” Hudson said, you probably shouldn’t. It’s dangerous and can lead to heatstroke. You may consider cooling clothes that work with your body to keep you cooler and more comfortable.)
4. Hold ice, cold towels or cool water to the skin
If you have something like a cold towel or a water bottle, put it on your or the other person’s neck, armpits or groin.
While you wait for help to arrive, you can even spray them down with cold water or put them in a cold shower — anything to cool them off. Cold water immersion or an ice bath is one treatment for heatstroke that doctors may use at the hospital.
Don’t force a drink on someone experiencing heatstroke, the CDC says. This is different advice than for someone who’s experiencing heat exhaustion, which typically comes before heatstroke. While someone with heat exhaustion may be given sips of water or sports drink, a person experiencing heatstroke may be confused, lose consciousness or have an altered state of consciousness.
“Because they have a depressed or altered level of consciousness, it may affect their ability to swallow safely so it’s probably better not to give them anything to eat or drink,” Hudson said.
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Before and after heatstroke: Check on your neighbors
Some people are more susceptible to heat illness and heatstroke, such as older adults, younger children, people with mobility issues, certain health conditions and those taking certain medications, including common drugs like blood pressure or antidepressant medications.
In case of a heat wave, be especially mindful to check in with your elderly neighbor down the hall or a friend who has trouble getting around, according to Hudson.
“This is the time that we really suggest people check on their neighbors,” she said. “Especially in places where people don’t have access to air conditioning or don’t have a way to get someplace cool.”
“They may be feeling poorly but can’t do anything about it,” Hudson added.
