What is Heat Stroke?

Heat stroke is a medical emergency condition that occurs when the body's core temperature increases above normal levels (usually above 104°F or 40°C) due to prolonged exposure to high temperatures or physical exertion in hot and humid conditions. Heat stroke is a severe form of heat-related illness and can cause damage to the brain, heart, kidneys, and other organs. Heat stroke can even be fatal if not treated promptly.


There are two types of heat stroke.

Exertional heat stroke

This is a condition in which the core body temperature rises as a result of vigorous physical exercise in hot conditions. Exertional heat stroke can happen to anyone who exercises or works in hot weather, but it's more likely to occur in individuals who aren't adapted to high temperatures.

Non-exertional heat stroke

This sort of heat stroke develops when exposed to hot, humid weather for an extended period. It is prevalent in older folks and those who have chronic conditions.


Common symptoms of heatstroke include

  • High body temperature greater than or equal to 104°F or 40°C
  • Altered mental state or confusion
  • Slurred speech
  • Seizures 
  • Profuse sweating 
  • Dry or hot skin
  • Nausea
  • Vomiting
  • Increased heart rate
  • Increased respiratory rate
  • Excessive thirst 
  • Headache 
  • Muscle cramps
  • Loss of consciousness

Symptoms of heatstroke can sometimes look similar to other conditions, like a heart attack. Also, some people feel mild signs of heat exhaustion before progressing to heat stroke.


Heatstroke occurs when the body can't cool itself down through its natural thermoregulatory system (hypothalamus) in response to hot temperatures. Typically hypothalamus sets your temperature at about 98.6 degrees Fahrenheit. But if the body takes in more heat than it releases, internal temperature rises above this set point causing heat stroke.

Risk factors

Some common risk factors for heat stroke include:

High temperatures

Exposure to high temperatures and humidity for extended periods is the primary risk factor for heat stroke.


Older adults and children are at higher risk of heat stroke because of their inability to regulate their body temperature effectively.

Health conditions

Certain medical conditions such as heart disease, lung disease,obesity, and diabetes can make it more difficult for the body to maintain its temperature.


Some medications, like antihistamines, diuretics, and beta-blockers, can interfere with the body's natural ability to regulate its temperature.


Lack of adequate fluid intake or excessive sweating can lead to dehydration, which increases the risk of heat stroke.

Wearing excess clothing

Over clothing prevents sweat from evaporating quickly and cooling the body.

Alcohol and drug use

Alcohol and drugs can impair judgment and interfere with the body's ability to regulate temperature, making individuals more susceptible to heat stroke.

Strenuous physical activity

Engaging in strenuous physical activity in humid and hot conditions can increase the risk of heat stroke.


Heat stroke can result in various complications, depending on how long the temperature rises. Severe complications of heat stroke include:

Vital organ damage

Without a quick response to reduce body temperature, heatstroke may trigger the brain and other vital organs to swell, possibly resulting in permanent damage.


Without prompt and adequate treatment, heatstroke can be fatal.


The diagnosis of heat stroke is usually based on a combination of clinical symptoms and physical findings. If you suspect that someone is experiencing heat stroke, it is essential to pursue medical attention immediately. A healthcare provider will typically perform the following assessments and tests:

Physical exam

The healthcare provider will perform a physical exam to check for signs of dehydration, heat exhaustion, and heat stroke.

Core body temperature

The healthcare provider may use a thermometer to check the person's core body temperature. A temperature of 104°F or higher usually indicates heat stroke.

Blood tests

Blood tests may be performed to check for electrolyte imbalances or other complications of heat stroke.

Urine tests

Urine tests may be performed to check for kidney damage or dehydration signs.

Imaging tests

Imaging tests, such as a chest X-ray and CT scan, may be performed to check for complications, such as pneumonia or brain swelling.

Other tests

Other tests, such as an electrocardiogram (ECG) or arterial blood gas test, may be performed to check for heart or lung complications.

First aid

Heat stroke is a severe condition that requires prompt treatment. Here are the steps to take if you suspect someone is experiencing heat stroke:

Move the person to a cooler place

If possible, move the person to a cooler environment, such as a shaded area or air-conditioned room.

Remove excess clothing

Remove any unnecessary clothing to help the body cool down.

Cool the person down

Use any available means to help cool the person's body, such as placing them in a cool bath or shower or using a spray bottle or fan to mist the skin with water.

Provide fluids

Offer the person cool water or other fluids to help them rehydrate.

Seek medical attention

Heat stroke sometimes is a medical emergency, and it is important to seek medical attention immediately. Call emergency services or take the person to the nearest hospital.

Monitor vital signs

While waiting for medical assistance, monitor the person's vital signs, including pulse and breathing rate.

It is important to note that early recognition and prompt treatment of heat stroke can greatly improve the prognosis and reduce the risk of complications.


The time it takes to recover from heat stroke varies from person to person. A person recovering from heat stroke usually spends one to two days in the hospital. If any vital organ is affected by heat stroke, the patient will need time to recover.

Precautions to be taken to prevent heat stroke

Stay hydrated

Drink plenty of fluids and water to keep your body hydrated. Avoid alcohol and caffeine, as they can cause dehydration.

Dress appropriately

Wear light-coloured, loose-fitting clothing that allows air to circulate freely around your body.

Avoid peak heat hours

Stay indoors or in the shade during peak heat hours, typically from 10 a.m. to 4 p.m.

Take frequent breaks

Take frequent breaks in cool or shaded areas to avoid overheating. Try to avoid strenuous activities during the hottest parts of the day

Use sunscreen

Apply sunscreen with a minimum of SPF 30 to protect the skin against the adverse effects of the sun.

Cool down

Take cool showers or baths, or use cold compresses to cool down your body temperature.

Check on others

Check on elderly or vulnerable individuals who may be more susceptible to heat stroke.

Following these precautions can help prevent heat stroke and stay safe during hot weather conditions.

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Frequently Asked Questions

1. Can heat stroke kill you?

Yes, heat stroke is fatal if left untreated immediately.

2. How long does heatstroke last?

When treated quickly, heat exhaustion symptoms usually last 30 minutes or less. However, it could take anywhere from 24 to 48 hours for you to fully recover.

3. What organs are affected by heat stroke?

Heat Stroke can damage internal organs like the brain, liver, kidney, heart, lungs, etc.

4. What is heatstroke prevention?

Take the following precautions to avoid heatstroke in hot weather: Wear light, loose-fitting clothing. Excessive clothing or clothing that is too tight will prevent your body from cooling adequately. Sunburn should be avoided at all costs.

5. How long does heatstroke last?

When treated quickly, heat exhaustion symptoms usually last 30 minutes or less. It could take anywhere from 24 to 48 hours for you to fully recover. Drink plenty of water and find a cool area to rest and recover if you're suffering from heat exhaustion.