Heat Stroke Symptoms, Treatment, Prevention and More - Dr. Axe

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7 Ways to Stay Cool & Prevent Heat Stroke Symptoms


Heat stroke - Dr. Axe

Heat stroke is a medical emergency that occurs when the body can no longer cool itself. The body suffers from dehydration because it can’t release internal heat into the environment, resulting in core temperatures of over 104 degrees Fahrenheit.

The scary part is that most people aren’t aware that they are in danger of heat stroke — the most severe heat-related illness — until it’s too late. By then, they have become confused and delirious as a result of nerve damage.

To ensure that your health is never put in harm’s way because of hot weather, take preventative measures to keep yourself cool and stay hydrated. It’s also important to avoid actions that increase your risk of developing heat stroke, like engaging in physical activity that ups your chances of heat illness, such as hot yoga and exercising in the direct sun.

Heat Stroke vs. Heat Exhaustion

Heat stroke occurs when your body’s natural processes to regulate your core temperature begin to fail as you become overheated. It is the most serious phase of heat illness, when you become at risk of life-threatening symptoms.

Heat exhaustion is the phase right before heat stroke, when you begin to feel signs of heat illness, such as muscle weakness and fatigue.


The body regulates core temperature to maintain a constant temperature of 98.6 degrees Fahrenheit — even in the hottest or coldest environmental conditions. For this to be possible, the thermoregulatory system uses different physiological mechanisms in order to balance the heat produced inside the body and the amount of heat lost to the environment. When these mechanisms break down, heat stroke symptoms occur.

How exactly do we fight heat illness? Here’s what occurs naturally to prevent life-threatening symptoms of heat stroke:

  • When the temperature outside becomes too high, temperature receptors in the skin send messages to the hypothalamus, which is the processing center in the brain.
  • When you become overheated, you release heat by sweating and activating the muscles in your skin. Your blood vessels also begin to swell or dilate, causing noticeable redness. More warm blood then flows close to the surface of your skin so heat is lost through the skin and into the air.
  • Muscles in your skin work to increase heat loss by causing hairs to lay down flat, as opposed to raising them up in order to trap more warmth. Your skin glands also secrete sweat onto the surface of your skin in order to increase heat loss by evaporation. Your body will keep sweating, releasing internal heat, until your body temperature returns to normal.

Once your body’s core temperature rises, all of your innate processes that are in place to regulate your internal temperature break down, creating serious, even life-threatening problems, like organ damage and loss of consciousness.

Heat Stroke Symptoms

Before heat stroke symptoms develop, you will experience a few warning signs. Generally, heat-related illnesses occur in four stages, beginning with muscle cramping, leading to heat exhaustion and ending with heat stroke.

The Centers for Disease Control and Prevention provides a breakdown of these four stages:

1. Heat Syncope (Fainting)

Heat syncope, or fainting, occurs when your body tries to cool itself, which causes your blood vessels to dilate so much that blood flow to your brain is reduced. This usually occurs when a person has been working outside or has been physically active in a hot environment.

Besides fainting, a person experiencing heat syncope may feel dizzy, restless and nauseous.

2. Heat Cramps

Heat cramps, also known as muscle cramping, are one of the first sign of heat-related illness. You may feel like you pulled a muscle, even though you weren’t doing anything strenuous.

Muscle aches and cramping are huge warning signs that you are dehydrated and need to get somewhere cool and drink water before your symptoms worsen.

3. Heat Exhaustion

Heat exhaustion happens when the heat begins to make you feel uncomfortable and ill, leading to symptoms, such as:

If left untreated, heat exhaustion can advance to heat stroke.

4. Heat Stroke

Heat stroke is the most serious of all heat-related illnesses. It is a medical emergency because it can lead to serious brain damage, organ failure and even death.

The most common heat stroke symptoms include:

  • body temperature above 103 degrees Fahrenheit
  • rapid and strong pulse
  • shallow breathing
  • hot, red, dry or moist skin
  • severe headache
  • fatigue
  • minimal or no sweating, despite the heat
  • nausea and vomiting
  • muscle weakness
  • muscle cramps
  • dark-colored urine (even rhabdomyolysis)
  • delirium
  • confusion
  • seizures
  • unconsciousness

Heat stroke is so serious because it can lead to organ failure and even death. It immediately affects your cognitive function and can lead to impairment.

In fact, research shows that approximately 20 percent of patients who suffer from heat stroke have long-term, irreversible brain damage as a result.


That’s why some of the most common heat stroke symptoms are delirium and confusion. Your nerve cells are particularly vulnerable when the body becomes overheated, and your brain is made up of these nerve cells.

When you experience heat illness, the blood vessels dilate, and blood flow increases. This strains the heart as well.

Causes and Risk Factors

Data shows that when the heat index is higher than 95 degrees Fahrenheit, the number of deaths caused by heat illness increases. As you sweat in hot weather, you lose fluids and become dehydrated. If you aren’t drinking plenty of water to replace these fluids, you can develop heat stroke symptoms.

There are also factors that slow down the body’s ability to release heat into the environment in its attempt to regulate its core temperature. Aside from being in very high temperatures, wearing dark or heavy clothing, being in direct sunlight, and engaging in physical activity are all contributing factors.

Here are more risk factors:

  • People aged 65 years or older: Elderly people, aged 65 years or older, have a harder time sensing that their bodies are overheated, so they don’t respond quickly to signs of heat stroke. Older adults also have higher rates of medications that can increase the risk of heat-related illness because they interfere with the way the body reacts to stress and proper hydration.
  • Infants and children: Infants and children rely on adults to keep them cool and hydrated. Plus, they are more prone to heat stroke and other heat-related illnesses because of their greater surface area to body mass ratio. This allows for more heat transfer from the environment to the body. Researchers report that children can’t evaporate heat as well as adults because little ones have slower sweat rates, and it takes more time for them to start sweating. Children also have less of a thirst response so they may not realize that they are becoming dehydrated.
  • People with chronic medical conditions: Research indicates that prevalence of heat stroke and other heat illness is higher among people with ongoing medical conditions, including obesity, cardiovascular disease, diabetes and respiratory disease. These conditions don’t allow the body to adapt to changes in environmental conditions as easily or quickly. People with mental illness are also at a higher risk of heat stroke because they may not realize when the body is becoming overheated and dehydrated. Social isolation is associated with adverse health effects from heat so people who are often home alone may be more likely to develop heat stroke symptoms.
  • People without access to air conditioning: Research shows that associations between heat and mortality are reduced or even absent in communities with high access to, or use of, air conditioning. Data also shows that individuals who own air conditioners have a reduced risk of heat-related illness.
  • Athletes: The CDC reports that the leading cause of death or disability among athletes who train or compete in high temperatures during the late summer and early fall months is heat-related illness. Research suggests that the risk is particularly high in the month of August.
  • People who work outdoors: Heat stroke and illness caused by hot weather are very common among people who work outdoors in hot climates. An epidemiological review published by the National Institute of Occupational Safely and Health found that at-risk workers include fire fighters, construction workers, farmers, soldiers and manufacturing workers who work around process-generated heat.

Related: Tips for Working Out in the Heat Safely (Plus Its Benefits)

Prevent heat stroke symptoms - Dr. Axe

Diagnosis (When Is It an Emergency?)

If you’re with someone who is displaying signs and symptoms of heat stroke, such as trouble breathing, dry skin, fatigue, muscle weakness and delirium, call 911 immediately. Then move the person to a cool place.

Try to cool him down by applying a cold compress or ice pack to his forehead or even pouring cool water over his body. Then wait until medical professionals take over.

Don’t hesitate to call for help, as heat stroke is a serious medical emergency. Immediate treatment is vital.

Treatment and Prevention

Studies show that when cooling is quickly initiated, and both the body temperature and brain function return to normal within an hour of symptom onset, most patients recover fully.

For patients suffering from heat stroke, cold water immersion is one of the most common ways to cool the patient’s core temperature quickly. The patient must be exposed to cold temperatures immediately in order to prevent organ breakdown and death.

The patient also may be given intravenous (IV) hydration and be transported to a hospital if he’s not already at one. Intravenous hydration is continued for 24 to 72 hours. In severe cases, medical professionals will administer IV magnesium sulphate to relieve muscle cramping.

To prevent heat stroke, take the following precautions when exposed to hot temperatures:

1. Drink Plenty of Water

The most important thing you can do to avoid heat stroke is to drink more water than you usually do because you are losing fluids through sweat. Drink two to four cups every hour when you are outside or exercising.

Don’t wait until you are thirsty to start drinking fluids. By then, you are already becoming dehydrated and putting yourself at risk of heat stroke.

Also, make sure that your children and others at a higher risk of heat stroke drink enough water throughout the day.

If you’re not a fan of drinking water all day, there are other beverages that will help you to stay hydrated, such as fruit smoothies, veggie juice, seltzer, lemon or lime water, and kombucha.

2. Eat Hydrating Foods

In order to avoid dehydration and the possibility of heat stroke, eat fruits and vegetables that are hydrating. They have a high water content and contain valuable electrolytes, which help you maintain fluid balance, keep blood pressure levels stable and help with nerve signaling, just to name a few roles of these vital nutrients.

Some of the best hydrating foods to beat heat stroke symptoms include:

  • coconut water
  • watermelon
  • oranges
  • grapefruits
  • pineapple
  • berries
  • bananas
  • grapes
  • kiwi
  • cucumber
  • bell peppers
  • carrots
  • zucchini
  • avocado
  • tomatoes
  • radishes
  • iceberg lettuce
  • broccoli

3. Avoid Sugary Drinks, Alcohol and Caffeine

It’s important to prevent dehydration by avoiding the consumption of sugary, sweetened drinks, alcohol and caffeine. All of these dehydrating beverages cause increased urination and electrolyte loss.

Plus, consuming too much sugar can lead to inflammation. This makes the symptoms of heat stroke even worse.

Although sports drinks are marketed to keep you hydrated during physical activity, many of these products contain a ton of added sugars and synthetic flavorings, so opt for natural electrolytes instead.

4. Avoid Direct Sunlight

To avoid developing heat stroke or other heat-related illnesses, limit your time outdoors on those hot days, especially midday when the sun is at its hottest. If you’re outside on a very hot day, stay in the shade. If you’re in an open space, bring an umbrella for protection.

For athletes who train outdoors, schedule your workouts earlier or later in the day when there are cooler temperatures.

5. Stay in an Air-Conditioned Building

You have to keep your body temperature cool during times of extreme heat. Using a fan alone as your cooling device isn’t going to be enough on those really hot days. You are going to need to stay in an air-conditioned home or building for as long as possible.

If you don’t have access to an air conditioner in your home, find an air-conditioned shelter in your community, and get some relief there for a few hours. Examples include shopping malls, movie theaters, local libraries, community centers and restaurants.

Studies also show that opening windows and using fans at the same time can offer protection against heat stroke during a heat wave. Just make sure you aren’t just circulating hot air, which can be dangerous.

Other ways to reduce your body temperature include:

  • taking a cool shower or bath
  • applying a cool compress to your head or the back of your neck
  • wearing lightweight and light-colored clothing
  • avoiding strenuous activity

6. Check your Medications

Some medications can increase your risk of heat stroke because they affect how your body reacts to the heat or they interfere with your salt and water balance. Medications that may alter your ability to deal with high temperatures include:

  • antibiotics
  • antidepressants
  • antipsychotics
  • antihistamines
  • drugs for heart disease, blood pressure and cholesterol
  • laxatives
  • diuretics
  • medications for seizures

If you’re taking any of these kinds of medications, talk to your doctor about your increased risk of heat stroke.

7. Check on Those at Risk

On those really hot days, make sure to check on people who are at a greater risk of developing heat stroke symptoms. These include people over the age of 65, people with chronic medical conditions, infants and children, and people who don’t have air conditioning in their homes.

Research also shows that social isolation is associated with an increased risk of heat-related illness. This includes people who are unmarried or widowed, living alone, or those who tend to stay home all day.

Make sure your loved ones have access to a cool place and that they’re drinking enough hydrating fluids. Never leave infants or children in a parked car. Also, make sure to dress them in loose, light clothes.

Don’t forget your pets, too! They can develop heat-related illnesses from being left outside in the heat for too long and not having access to liquids.


  • Heat stroke is a medical emergency that occurs when the body’s core temperature reaches above 103 degrees Fahrenheit and puts you at risk of organ failure and death.
  • The four stages of heat illness are heat syncope, heat cramps, heat exhaustion and, the most severe stage, heat stroke.
  • The people at the greatest risk of developing heat stroke include the elderly, infants and children, people with chronic medical conditions, people without access to air conditioning, athletes, and people who work outdoors.
  • When someone suffers from heat stroke, her body temperature most be reduced immediately, and she must be hydrated intravenously until her fluid levels return to normal.
  • To prevent heat stroke naturally, drink plenty of water throughout the day, avoid dehydrating beverages, stay in an air-conditioned place, wear loose and light clothing, avoid direct sunlight, check that your medications aren’t interfering with your hydration, and check on loved ones who are at risk of heat-related illness.

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