Know the symptoms of heatstroke — and how to treat and prevent heat-related illness

• Heatstroke symptoms can include a core body temperature above 104 degrees Fahrenheit, mental confusion or slurred speech, flushed skin, rapid breathing and heart rate, and even unconsciousness.
• Heatstroke requires immediate medical attention, as it can cause damage to vital organs or death if left untreated —call 911 if you or someone else is experiencing these symptoms.
• To prevent heatstroke, it's important to stay cool, drink lots of water, and avoid exercise in the hottest parts of the day during the summer months.
• This article was medically reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.

Heatstroke can occur when your core body temperature reaches 104 degrees Fahrenheit or higher, and your body is unable to cool itself down.

"This is one of those rare, true athletic emergencies," says Joshua Scott, MD, primary care sports medicine physician at Cedars-Sinai Kerlin-Jobe Institute. "Heatstroke is like a heart attack. You have to treat it immediately."

Before someone experiences heatstroke, they will feel symptoms of heat exhaustion, such as heavy sweating and a rapid pulse. This often occurs when you're outside during hot and humid temperatures, and especially if you're working or exercising at that time.

If heat exhaustion escalates to heatstroke, here's how you can recognize the symptoms, and how to treat them.

Heatstroke symptoms

Along with a temperature above 104 degrees Fahrenheit, the major signs of heatstroke include:

• Mental confusion or slurred speech. When body temperature gets above 104 degrees Fahrenheit, proteins in the brain can start to break down, which can trigger changes in mental status. "They will be very confused and not be able to carry on a normal conversation with you," Scott says.
• Unconsciousness. Fainting can be a sign of heat exhaustion, but you should be able to wake someone with heat exhaustion fairly easily, Scott says. That isn't the case with heatstroke. "If they're passed out and not able to be awoken, if they're hot and their core temperature is elevated, then you should strongly consider heatstroke," he says.
• Rapid heart rate and trouble breathing. High heat puts stress on all of your bodily functions, and as a result, you may experience a racing heart rate along with shortness of breath, shallow breathing, or hyperventilating.
• Flushed skin. Your skin might appear red as your body heats up.

Treatment

While heat exhaustion can be treated at home by cooling yourself down, heatstroke always requires immediate medical treatment because it can cause brain damage, organ failure, and even death if not promptly treated.

If you are with someone who you think may be experiencing heatstroke, you should try to cool them down before they get to the hospital to slow down the potential destruction of organs, Scott says. Here's how:

• Submerge them in cool water, such as in a bathtub.
• Spray the person with water and then place them in front of a fan.
• Place cool cloths or ice packs on the neck, armpits, and groin.

In the hospital, heatstroke may require an IV to treat dehydration, and in severe cases, your doctor may need to manage multi-system organ failure.

Prevention

To prevent heat-related illnesses, it's always best to refrain from extended physical activity during the hottest parts of the day, between 3 p.m. and 4:30 p.m. If you have to be outside in hot and humid conditions, it's vital to stay hydrated and take frequent resting breaks.

If you notice symptoms of heat exhaustion, like heavy sweating, rapid pulse, fatigue, nausea, lightheadedness, or weakness, take them seriously and cool yourself down by:

• Moving to a shaded area or going indoors
• Removing unnecessary or tight clothing
• Taking a cool bath or shower
• Drinking fluids
• Placing cold, wet cloths on your head, neck, and armpits

The most at risk populations for heatstroke include children under four years of age and older people over 65.

A child's body can heat up three to five times faster than an adult's, so it's especially important to watch for signs of heat exhaustion in children.

In the summer, the inside of a car can heat up by 20 degrees Fahrenheit in just 10 minutes, and cracking a window is not a sufficient method of cooling, according to the American Academy of Pediatrics. A child should never be left in a hot car for any period of time.

Also check in on your older neighbors and loved ones during the hotter months to make sure they have what they need to stay cool and hydrated.

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