Construction worker at risk of heatstroke wiping sweat off their forehead on a hot day


Heatstroke: Symptoms, causes and treatment

  • More than 600 people in the U.S. are killed by extreme heat every year, according to the CDC.

Many want to get the most out of the Minnesota summer weather while it lasts. But as temperatures rise, so does the risk of developing heatstroke. Recognizing the early warning signs of heatstroke in yourself and others can save lives.

What is heatstroke?

Heatstroke, also known as sunstroke or hyperthermia, occurs when your body overheats to 104°F or higher and can’t cool down. Heatstroke is caused by exposure to hot weather and usually starts with heat exhaustion.

Heat exhaustion vs. heatstroke

These two heat-related illnesses are often mixed up because of similar symptoms and since heat exhaustion is an early warning sign of heatstroke. One of the most significant differences is that a heatstroke is an emergency that requires immediate medical attention.

Symptoms unique to heat exhaustion include:

  • excessive sweating
  • muscle weakness or heat cramps
  • cold, pale and moist skin
  • a weak pulse
  • a body temperature of 100.4° to 103° F

Symptoms of heatstroke 

Heatstroke can happen quickly, sometimes without any symptoms or warning signs. Symptoms are often difficult to recognize in yourself because heatstroke often causes confusion.

Warning signs and symptoms to monitor in yourself and others include:


  • Head discomfort. Exposure to heat may cause lightheadedness, a throbbing headache or fainting. Fainting is a common warning sign of heatstroke.
  • Rapid and shallow breathing. During a heatstroke, your body works harder to supply the brain with oxygen. A lack of oxygen can cause fainting.
  • Lack of sweat. Often caused by dehydration, one of the most detectable signs of heatstroke is the absence of sweat. Without sweat, your body loses a vital cooling mechanism to regulate temperature.
  • High body temperature. Seek medical attention if your body temperature is 103° F or higher.
  • Sudden behavioral changes. Slurred speech, agitation, confusion, difficulty concentrating, irritability, changed mental status and seizures are common warning signs of heatstroke.
  • Increased heart rate. Your heart works harder to fight heat stress and keep your body cool, causing your pulse to surge.

How to treat heatstroke 

Heatstroke is a medical emergency that can be fatal or cause permanent damage to the brain and other vital organs when medical help is delayed. That’s why it’s critical to get immediate medical attention if you or someone nearby is experiencing a heatstroke.

During a heatstroke, call 911 and use these strategies to lower body temperature until paramedics arrive:

  • Move to a cooler place such as an air-conditioned or shady area.
  • Place a cool cloth on their forehead.
  • Apply ice packs to their neck, cheeks, hands, back, soles of the feet, armpits and groin.
  • Cover them in cool (not too cold) water using a bath, shower, garden hose or a sponge.
  • Give them enough cool water to rehydrate. Avoid alcoholic, caffeinated and sugary beverages.

Continue first aid until medical help arrives or their body temperature is below 102°F.

Risk factors and causes of heatstroke

Heatstroke can happen to anyone, but some factors can put you more at risk. Risk factors include:

  • Humidity. You’ve heard people say, “It’s not the heat, it’s the humidity.” That’s because humidity makes you feel hotter than the actual temperature. When extreme temperatures and humidity combine, chances of experiencing heatstroke escalate.
  • Exposure to hot temperatures. In Minnesota, the dramatic temperature shift from winter to spring can be shocking. If you decide to brave the heat, limit physical exertion and exposure to extreme temperatures until your body is acclimated.
  • Age. Children 4 and younger and adults 65 and older are more at risk of heatstroke. Babies, toddlers and older adults don’t lose heat as easily or produce enough sweat to cool down.
  • Access to air conditioning. A lack of air conditioning can dramatically increase heatstroke risk, especially among adults 65 and older.
  • Your medications. Some medications impact how your body regulates temperature and stays hydrated.
  • Your occupation. Pace yourself and know your limits if you work outside. Spend time in an air-conditioned vehicle or nearby facility during your breaks.
  • Existing health conditions. Heart disease, mental illness, obesity and other conditions can increase the risk of heatstroke. A history of heat-related illnesses or a previous heatstroke also increases your risk.

Talk with your provider about managing health conditions and medications to decrease heatstroke risk.

How to prevent heatstroke

  • Limit alcohol. Overconsuming your favorite adult beverages could lead to dehydration, a hangover or a heat-related illness. That’s because drinking alcohol makes it more difficult to control your body temperature.
  • Stay hydrated. Drinking enough water helps your body stay hydrated and produce enough sweat. Think of water as the fuel for your sweat. Despite its bad reputation for being “gross” and “smelly,” sweat deserves more credit for regulating your body temperature.
  • Stay inside with air conditioning if possible. Turn on your air conditioner or sit by a fan to cool down. If your home isn’t air-conditioned, spend time in public spaces with air conditioning during the hottest times of the day.
  • Slow and steady beats the heat. Physical activity is good for your overall health. Exercise and hot weather combined can also increase your chances of heatstroke. Lighten up your routine or move your workout indoors to avoid heat-related risks.
  • What to wear. Wear loose, lightweight, breathable and light-colored clothing to prevent heat-related illnesses.
  • Don’t forget the sunscreen. Sunburn makes it challenging for your body to stay cool.



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