What Are Heat Stroke Symptoms? Recognize the Signs

Heat stroke is the most serious type of heat illness. It is a medical emergency. The main sign of heat stroke is a body temperature over 104°F (40°C).1 Other signs are feeling sick, having seizures, being confused, lost, or fainting. Sometimes, it can lead to coma.1 Without quick help, it can cause lasting harm or death.2 Acting fast is key – dial 911 and start cooling the person immediately.

Key Takeaways

  • Heat stroke is a life-threatening medical emergency requiring rapid cooling and emergency care.
  • The hallmark symptom is a core body temperature above 104°F (40°C).
  • Other common signs include nausea, confusion, altered sweating, and rapid breathing.
  • Heat stroke can result in permanent disability or death if not treated promptly.
  • Calling 911 and initiating first aid cooling measures are critical first steps.

Overview of Heat Stroke

Heat stroke is a severe, life-threatening condition from staying in high temperatures too long. It happens along with dehydration, which makes the body’s cooling system fail.1 It’s when your body’s core temperature goes above 104°F (40°C) and starts impacting the brain.1 You can get heat stroke from being in a hot place for a long time (classic heat stroke) or from working hard in the heat (exertional heat stroke).1

Definition and Causes

A sign of heatstroke is having a body temperature of 104 F (40 C) or higher.1 Doing lots of physical activity in hot weather can cause exertional heatstroke.1 Heatstroke usually happens after being in hot, humid weather for a while. It’s more common in older adults and those with long-term health issues.1

Risks and Complications

Some things that make you more at risk for heatstroke are being very young or over 65, doing hard activities in hot weather, and sudden very hot weather.1 If not treated, heatstroke can damage vital organs or be deadly.1 Staying safe from heatstroke means wearing light, loose clothes, drinking lots of water, avoiding sunburn, and never leaving people or pets in parked cars.1

What are Heat Stroke Symptoms?

The main sign of heat stroke is a body temperature over 104°F (40°C).1 This shows a person needs immediate help. Symptoms also include confusion, slurred speech, and seizures.3

Changes in Sweating

The body might stop sweating or only be a little wet.3 This change is a big warning that the body can’t cool itself.

Nausea and Vomiting

Feeling sick or throwing up is common in heat stroke.3 It makes dehydration worse and can affect your body’s salts a lot.

Flushed Skin

If someone has reddish skin, it could mean heat stroke. When the body can’t cool down, the skin gets red.

Rapid Breathing and Heart Rate

Fast breathing and heartbeat try to cool down the body.3 It’s a sign that the situation is serious and needs quick action.


One big headache often comes with heat stroke.3 This happens as blood pressure in the brain goes up with the heat.

Heat stroke is very serious and needs fast treatment.1 Acting quickly can save someone’s life.1

Types of Heat-Related Illnesses

Heat stroke is the most severe heat-related illness. But there are other conditions too. These include heat exhaustion, rhabdomyolysis, heat syncope, heat cramps, and heat rash. It’s important to know what each is. This knowledge helps prevent heat stroke from happening. Let’s look into each type and what makes them different.

Heat Exhaustion

Heat exhaustion happens when your body loses too much water and salt. This can occur after you’ve been in the heat for a long time. Symptoms are a headache, feeling sick, dizzy, and weak.4 It means your body can’t cool down well.


Rhabdomyolysis makes your muscles break down quickly. It’s a rare but serious problem. It can cause issues like an irregular heartbeat, seizures, and kidney damage.2

Heat Syncope

Heat syncope, or fainting, is pretty common in hot weather. It often happens after standing for a long time or getting up quickly. Dehydration and not being used to the heat can add to the risk.2

Heat Cramps

Heat cramps cause painful muscle spasms. They’re common in hot weather and happen when someone loses a lot of sweat. This can throw off the body’s balance of electrolytes.2

Heat Rash

Heat rash, also called prickly heat, results from too much sweating. It forms red bumps or tiny blisters, mainly in the neck, chest, and groin areas.2

These heat-related troubles are not as severe as heat stroke. But, they still need to be taken seriously. Knowing the signs and getting help fast can prevent worse problems.

types of heat related illnesses

When to Seek Medical Attention

If you think someone has heat stroke, it’s vital to get help fast by calling 911.1 Heat stroke is a serious situation that can harm organs or cause death.1 Before help arrives, start cooling them off. Move the person to a cooler area, take off extra clothing, use a fan, and add cold water or ice packs.1 Always remember, even if the signs are light, getting a doctor’s help is extremely important.1

Heat stroke needs quick medical care.1 If you or someone shows its signs, like high body temperature or mental changes, don’t wait.1 Call 911 and start first aid right away.1 Getting medical help fast can save a life when it comes to heat stroke.

Risk Factors for Heat Stroke

Several things can make you more likely to get heat stroke. Knowing these risk factors for heat stroke is key. It helps in preventing and treating this serious condition.


Both the very young and older adults can be at risk.1 It’s more common in older folks and those with chronic illnesses.1

Exertion in Hot Weather

Working hard in the heat can cause exertional heatstroke. This is true especially for those not used to hot weather.13

Sudden Exposure to Heat

Being suddenly hit by high temperatures can also raise your risk. This often happens in early summer heat waves.1

Lack of Air Conditioning

Not having AC can make it hard for your body to stay cool. This is a big risk factor.13

Medications and Substances

Some medicines and substances can also increase your risk. These include diuretics, beta blockers, and antidepressants. Using alcohol or drugs has the same effect.13

Health Conditions

If you have certain health problems, you are at a higher risk too. This includes conditions like heart, lung, or kidney diseases, obesity, high blood pressure, and diabetes.13

If you fit into any of these categories, take care. Stay cool and drink plenty of water in hot weather. This can save you from the danger of heat stroke.

Risk factors for heat stroke

Diagnosing Heat Stroke

To diagnose heat stroke, look for a body temperature over 104°F. Use a rectal thermometer for the most accurate result.5 Signs also include confusion, no sweating, fast heartbeat, and body organ issues.1 Doctors check medical history and what the person has been doing to confirm heat stroke.1 Quick diagnosis is vital for starting emergency care right away.

Diagnostic Criteria for Heat StrokeImportance
Core body temperature above 104°F (40°C)The sign that marks heat stroke, demanding specific and precise thermometer readings5
Altered mental stateGetting confused, acting out, or not making sense are possible symptoms of heat stroke1
Lack of sweatingIf someone stops sweating even when it’s hot, it’s a key signal of heat stroke over milder heat issues1
Rapid heart rateAn increased heart rate can show the body is trying hard to cool down in heat stroke1
Organ dysfunctionWithout quick treatment, heat stroke can harm the liver, kidneys, and other essential parts of the body2

Knowing the person’s health and activities is key to recognizing heat stroke.1 Fast diagnosis is crucial to start cooling and treating immediately. This helps prevent lasting damage or death.2

Treating Heat Stroke

If you think someone has heat stroke, act fast. Call 911 right away and start cooling them down.3

First Aid Measures

First, move them to a cool spot and take off extra clothes. Then, cool them quickly with cold water or ice. You can also use a fan to help. Keep checking their temperature and cooling them until it’s between 101-102°F (38-39°C).3

Emergency Medical Treatment

In the hospital, doctors will hydrate them and check their minerals. They might give drugs to lower fever and swelling.3 Fast cooling at this point is key to stop harm or death.1

Acting fast to cool the body saves lives. It also improves the chances of recovery.1

Preventing Heat Stroke

Heat stroke can be life-threatening but is preventable with the right steps. By taking precautions, you can lower your risk in hot weather.1

Clothing and Sun Protection

Dress to avoid heat stroke by choosing light, loose clothes in light colors. Protect your face and neck with a wide-brimmed hat from the sun. Also, use sunscreen with an SPF of 30 or more.1


Keep hydrated. Drink lots of water and drinks with electrolytes, especially when it’s hot or you’re active.1 Stay away from tea, coffee, and alcohol since they make you lose fluids.3

Activity Modification

Change or move hard activities to cooler parts of the day, like early morning or evening. Avoiding the midday sun can help a lot.1 If you have to be out in the heat, take breaks in the shade or somewhere cool often.

Environmental Adjustments

When it’s really hot, go to places with air conditioning. Without it, open windows and use fans to cool down at home.3 Keep an eye on your fluid intake, urine color, and weight to see if you’re staying hydrated enough.1

Using these steps can lower your chance of getting heat stroke and keep you safe in hot weather. Knowing what to do and watching for warning signs make a big difference.132

Heat Stroke in Specific Populations

Older adults often have a hard time regulating their body temperature, putting them at risk for heat stroke. This risk is higher if they don’t have air conditioning.3 Infants, kids up to age 4, and adults over 65 are also more likely to suffer in the heat.3

Older Adults

Seniors without AC, whether living in apartments or houses, face a greater danger of heat stroke.3 They find it harder to stay cool, making them more prone to heat illnesses.1 This makes it crucial for them to avoid extreme heat, drink plenty of water, and find ways to stay cool.

Athletes and Workers

Athletes and those who work outside can get exertional heat stroke.1 This is more likely if they push themselves in the heat.1 Heat cramps are also common in people who do strenuous work and sweat a lot.2

People with Chronic Illnesses

If you have chronic conditions, like heart or lung problems, the risk goes up.3 Certain medicines, like diuretics, can make things worse.3 People in this situation should talk to their doctors about handling extreme heat.3

For these at-risk groups, being careful about the heat is super important. They should avoid the sun too much, drink plenty of water, and find ways to keep cool. Quick action at the earliest signs of heat problems can prevent more serious issues.

Heat Stroke and Heat Index

The risk of heat-related illness goes up a lot when it feels like 90°F (32°C) or more.3 High humidity slows down sweating, which cools us off. Yet, full sunshine can make it feel even hotter by 15°F (8°C). So, keeping an eye on the weather and health tips is crucial during hot spells, especially in cities where heat and pollution gather.3

Key Heat Stroke StatisticsImpact
Heat stroke is the most serious heat-related illness, with the body’s temperature rising rapidly to 106°F or higher within 10 to 15 minutes.2Heat stroke can cause permanent disability or death if emergency treatment is delayed.2
Risk of heat-related illness dramatically increases when the heat index climbs to 90 degrees or more.3People living in urban areas may be more prone to develop heat stroke during prolonged heat waves due to the heat island effect.3
Children up to age 4 and adults over age 65 are particularly vulnerable to heat-related illnesses.3Certain health conditions and medications increase the risk of heat stroke.3

Staying informed about the heat index and how to stay safe is key in preventing problems like heat stroke. It’s especially important for those most at risk. By understanding how the heat index affects health risks in hot weather, we can all be prepared.

Recovering from Heat Stroke

After a heat stroke, someone might not feel well in high temperatures for a week.3 They should avoid heat and hard workouts until a doctor says it’s okay. This gives the body time to get back its ability to handle heat.3 Drinking a lot, staying cool with air conditioning, and not spending too much time outside is important. It helps prevent another heat issue.3

Recommended Practices During Heat Stroke Recovery
  • Avoid hot and humid environments
  • Refrain from strenuous physical activity
  • Stay well-hydrated with water, fruit juice, or vegetable juice
  • Utilize air conditioning or seek cool, shaded areas
  • Consult a doctor before resuming normal activities

Listening to your body is key during recovery from heat stroke.3 Following the doctor’s advice helps ensure a complete and safe recovery.3 Avoiding too much heat or exercise is vital to reduce the risk of more harm.3 With care, you can heal, become stronger, and handle high temperatures better.


Heat stroke is very dangerous and needs quick cooling and medical help. Knowing the signs and symptoms is key. That means watching for a very high body temperature, acting differently, and not sweating right. Recognize these warnings to act fast. This is especially vital for the elderly, athletes, and those with long-term sicknesses.1It can often be stopped by drinking plenty of water, avoiding the heat, and using cool air.

In America, over 600 people die from heat stroke each year. The numbers have gone up from 1995 to 2015.6 While only a small amount of heat stroke from exercise leads to death, most other cases can be deadly. Even with care, up to 65% of these cases can end in death.6 Having the right knowledge on heat stroke can mean saving someone’s life when it’s really hot. Knowing the signs, how to treat it, and how to prevent it is very important.

When the body’s core temperature gets over 104°F (40°C), that’s a big warning for heat stroke.7 Get to a cooler place and use cold, wet cloths on the skin to cool down fast.7 If the signs keep getting worse or don’t go away, see a doctor right away. In some cases, heat stroke can get really serious and need immediate medical help.7


What are the symptoms of heat stroke?

When someone has a heat stroke, their body temperature goes above 104°F (40°C). They can act confused, or their speech might be mixed up. They might feel very angry or have trouble thinking clearly. Sometimes, they might not even be sweating. Other signs are feeling sick, throwing up, having red skin, fast breathing, and a quick heartbeat. They can also have a bad headache.

What are the different types of heat-related illnesses?

There are a few heat illnesses besides a heat stroke. Heat exhaustion, rhabdomyolysis, heat syncope, heat cramps, and heat rash are among them. These can happen before a heat stroke. It’s vital to spot the signs early and get medical help if needed.

When should I seek medical attention for heat stroke?

A: Heat stroke is very serious and needs quick medical treatment. If you think someone has it, call 911 right away. They should be checked by a doctor immediately. Even if the signs are not very severe, it could get bad quickly.

What are the risk factors for heat stroke?

Some things make people more likely to get a heat stroke. These include being very young or old, working hard in the heat, suddenly being in very hot weather, and not having air conditioning. Some medicines, health issues like heart or lung problems, being very overweight, and diabetes also raise the risk.

How is heat stroke diagnosed?

Doctors look for a high body temperature, above 104°F (40°C), to diagnose heat stroke. They use a thermometer placed in the rectum. They also ask about recent activities and health history to confirm it’s a heat stroke.

How is heat stroke treated?

Suspect a heat stroke – call 911 and start cooling off the person. Move them to a cool spot, take off extra clothes, fan them, and use cold water or ice packs. Doctors will give them fluids through an IV, balance their electrolytes, and possibly give them medications to reduce fever and swelling.

How can I prevent heat stroke?

To avoid a heat stroke, wear light clothing and protect your head from the sun. Drink lots of water, avoid the hottest times of the day, find cool places, and keep track of how much you drink and your urine color. This ensures you stay hydrated.

Who is at the highest risk for heat stroke?

The risk of heat stroke is highest for older people, athletes, and those working outdoors. It’s also greater for those with certain health problems. These include heart and lung diseases, obesity, and diabetes.

How does the heat index affect heat stroke risk?

When the heat index is over 90°F (32°C), the risk of heat stroke goes up a lot. It’s crucial to watch the heat index forecast and take steps to stay cool, especially when it’s very hot and humid.

What should I do after recovering from heat stroke?

After a heat stroke, avoid very hot weather and heavy exercise for about a week. A doctor should say it’s okay before you do these things. Your body needs time to recover and control its temperature well again.

Source Links

  1. https://www.mayoclinic.org/diseases-conditions/heat-stroke/symptoms-causes/syc-20353581
  2. https://www.cdc.gov/niosh/topics/heatstress/heatrelillness.html
  3. https://www.webmd.com/a-to-z-guides/heat-stroke-symptoms-and-treatment
  4. https://www.hopkinsmedicine.org/health/conditions-and-diseases/heatrelated-illnesses-heat-cramps-heat-exhaustion-heat-stroke
  5. https://www.mayoclinic.org/diseases-conditions/heat-stroke/diagnosis-treatment/drc-20353587
  6. https://en.wikipedia.org/wiki/Heat_stroke
  7. https://doctorondemand.com/blog/health/understanding-heat-stroke-symptoms-and-essential-solutions/