TL;DR
Heat stroke is much more than getting too hot; it’s a life-threatening emergency that can damage the brain and other organs within minutes. If someone becomes confused, faints, has a seizure, or loses consciousness in the heat, call 911 immediately and start cooling them right away. Knowing the difference between heat exhaustion and heat stroke, and acting fast, can save a life.
Hot weather can be uncomfortable and exhausting, but there’s a big difference between heat exhaustion and heat stroke. In fact, heat stroke is a severe medical emergency that can lead to organ damage. One reason it’s so dangerous is that it can happen quickly and unexpectedly, especially during heat waves, outdoor work, sports, crowded events, or in homes without air conditioning.
Many people confuse heat stroke with heat exhaustion. While both are caused by overheating, heat stroke is the more dangerous condition. Knowing the difference can save a life.
What Is Heat Stroke?
Heat stroke happens when the body can no longer maintain a safe internal temperature. Normally, the body cools itself by sweating and sending more blood to the skin. However, in extreme heat, high humidity, heavy exercise, dehydration, or poor ventilation, the body won’t be able to cool itself properly.
As a result, the body temperature rises to a dangerous level. A person may become confused, faint, stop responding normally, or even have a seizure. This is not something to “wait out.” Heat stroke requires emergency medical care.
A key warning sign is a change in mental state. Someone with heat stroke may seem:
- Confused
- Agitated
- Disoriented
- Dizzy or faint
- Unable to answer simple questions
- Unusually clumsy
- Very sleepy or hard to wake
- Unconscious
The skin may be hot, red, dry, or damp. Do not assume a person is safe just because they are still sweating, because heat stroke can occur with or without sweating.
Heat Exhaustion vs. Heat Stroke
While heat exhaustion is serious, it can be manageable if recognized and treated quickly. When someone is suffering from heat exhaustion, their body is under stress from the heat, but they have not lost their ability to regulate their body temperature.
Common signs of heat exhaustion include:
- Heavy sweating
- Weakness or tiredness
- Headache
- Dizziness
- Nausea or vomiting
- Muscle cramps
- Cool, pale, or clammy skin
- Fast pulse
- Intense thirst
In most cases, a person with heat exhaustion is still alert and able to talk clearly. While they may feel awful, they can usually follow instructions.
Heat stroke is different. It affects the brain and nervous system. The person may stop thinking clearly, act strangely, collapse, or lose consciousness.
Think of it this way:
- Heat exhaustion: The body is overheating and needs help cooling down.
- Heat stroke: The body’s cooling system is failing, and organs may be in danger.
If someone has symptoms of heat exhaustion and does not improve after cooling, or if they show confusion, fainting, seizure, or loss of consciousness, treat it as heat stroke.
Why Heat Stroke Is a Medical Emergency
Heat stroke is an emergency because high internal body temperature can lead to organ or cell damage. The longer the body stays overheated, the higher the risk of permanent damage or death.
Heat stroke can lead to:
- Brain swelling or injury
- Kidney failure
- Heart rhythm problems
- Muscle breakdown
- Shock
- Seizures
- Coma
- Death
This is why you should call emergency services immediately. Do not drive the person around looking for help unless emergency services are unavailable. Call 911 or your local emergency number and begin cooling the person right away.
Getting quick treatment can improve the outcome and prevent organ damage or death.
What To Do If You Suspect Heat Stroke
If you think someone has heat stroke, act immediately.
- Call 911 or local emergency services: Say that you suspect heat stroke. Give the person’s location and symptoms.
- Move them out of the heat: Get them into shade, air conditioning, or the coolest nearby place.
- Start cooling immediately: Do not wait for paramedics before taking action, and cool the person in whatever ways you can before they arrive.
- Remove extra clothing: Take off jackets, helmets, pads, or tight layers if you can do so safely.
- Keep them lying down: If they are confused, faint, or unconscious, keep them safe and monitor breathing.
- Do not give fluids if they are confused or unconscious: They could choke. Only give small sips of cool water if they are fully awake, alert, and able to swallow.
Effective Cooling Methods
The goal is to cool the body as quickly as possible. Use whatever safe method is available.
Good cooling methods include:
- Cold-water immersion: Place the person in a tub, kiddie pool, or large container of cold water if available and safe.
- Cool shower or hose: Spray or shower them with cool water.
- Wet cloths or towels: Place cool, wet towels on the body and replace them often.
- Ice packs: Place ice packs on the neck, armpits, and groin.
- Fan and mist: Wet the skin and fan the person to increase cooling.
- Remove heat-trapping gear: Take off sports equipment, work gear, or heavy clothing.
What NOT to do:
- Do not cover the person with dry blankets: You’ll trap heat.
- Do not give alcohol: Even if it’s cold, alcohol dilates blood vessels and accelerates dehydration.
- Do not give caffeine: Like alcohol, it’s a diuretic. It can also increase heart rate and metabolic heat production.
- Do not give fever-reducing medicine: Heat stroke is not the same as a fever from infection.
Who Is Most at Risk?
Heat stroke can happen to anyone, but some people are more vulnerable.
Higher-risk groups include:
- Older adults
- Babies and young children
- Outdoor workers
- Athletes
- People without air conditioning
- People with heart disease or chronic illness
- People taking certain medications
- People who are dehydrated
- People using alcohol or drugs
- Anyone left in a parked vehicle
Athletes and workers can develop heat stroke even if they are young and healthy. Exertional heat stroke can happen during intense activity, especially in hot or humid conditions.
Prevention Matters
The best treatment is prevention. During hot weather:
- Drink water regularly.
- Take breaks in shade or air conditioning.
- Wear light, loose clothing.
- Avoid hard activity during the hottest part of the day.
- Check on older adults, children, and neighbors.
- Never leave children, pets, or vulnerable adults in parked cars.
- Know the signs of heat illness before symptoms become severe.
The Bottom Line
Heat stroke is not “just overheating.” It is a medical emergency that can become deadly very quickly. Heat exhaustion may improve with rest, fluids, and cooling, but heat stroke requires emergency care. By completing a First Aid Course, you can learn the signs and symptoms of heat stroke and be prepared to respond confidently in an emergency.
When in doubt, treat it seriously. Call for help, move the person to a cooler place, and begin cooling immediately. Fast action can prevent organ damage and save a life.