Understanding Heatstroke: Symptoms, Diagnosis, and Treatment
Heatstroke: Symptoms, Diagnosis, and Treatment
What Is Heatstroke?
Heat exhaustion occurs when your body overheats due to prolonged exposure to high temperatures, often in combination with dehydration. This condition can impair the body's ability to cool itself and, if left untreated, can progress to heatstroke, which is a much more severe and life-threatening condition.
Heat exhaustion typically starts with symptoms like excessive sweating, dizziness, weakness, headache, and nausea. However, it can escalate quickly, leading to confusion, fainting, and rapid pulse. It is a sign that your body is struggling to regulate its temperature.
If you or someone else shows signs of heat exhaustion, it is important to cool down immediately by moving to a cooler environment, drinking fluids, and resting. If symptoms worsen or lead to heatstroke, seek emergency medical attention.
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| Heat Stroke Signs |
What causes heatstroke?
Heatstroke is caused by your body not being able to cool down effectively. Sweat is your body's way to cool you down. Your body usually keeps its normal temperature through the evaporation of sweat and by moving more blood towards your skin.
Difference between heat exhaustion and heatstroke
Heat exhaustion and heatstroke are both serious conditions caused by extreme heat, but they vary in severity. Heat exhaustion is less severe and typically presents with symptoms like heavy sweating, dizziness, nausea, weakness, and headaches. While it requires attention and rest, it isn't immediately life-threatening if treated properly. However, if left untreated, heat exhaustion can progress to heatstroke, which is far more dangerous and requires urgent medical care.
Heatstroke Symptoms
The hallmark symptom of heatstroke is a core body temperature above 104 F.
Other symptoms may include:
- Throbbing headache
- Dizziness and lightheadedness
- Lack of sweating despite the heat or excessive sweating
- Skin flushing
- Muscle weakness or cramps
- Nausea and vomiting
- Rapid heartbeat
- Rapid, shallow breathing
- Behavioral changes such as confusion, disorientation, or staggering
What's the difference between heat exhaustion, heat stress and heatstroke?
Heat stress happens when your body gets too hot and needs to cool down. You might feel thirsty, tired, and sweaty.
Heat exhaustion is more serious. You feel very weak, dizzy, and might have a headache or nausea. Your skin may be clammy. To treat heat exhaustion, you need first aid that includes rest, fluids and a cool environment.
Heatstroke is the most serious. Your body isn't able to cool itself anymore, and your temperature becomes dangerously high. You might:
- stop sweating
- feel confused
- lose consciousness
How do I know if I have heatstroke or heat exhaustion?
If you have heat exhaustion, you might have symptoms that are similar to heatstroke, but there are differences. In cases of heat exhaustion:
- Your body temperature will be normal or only slightly higher than usual.
- Your skin will be cool to touch, pale and clammy.
- Your body will continue to sweat, usually significantly.
Why is heatstroke an emergency?
Heatstroke can lead to permanent disability and death. It may trigger sudden events such as a heart attack or stroke and can worsen existing medical conditions.
Heatstroke needs immediate first aid to lower your body temperature as quickly as possible.
Types of heat stroke
There are two types of heat stroke:
- Classic (non-exertional) heat stroke. Heat in your environment (like a car, home or outdoor space) overwhelms your body’s ability to cool itself. Classic heat stroke typically affects children and adults over age 65. This is the type you hear about on the news during heat waves.
- Exertional heat stroke. You generate lots of heat through physical activity (metabolic heat), and it’s more than your body can handle. Exertional heat stroke often occurs when physical activity and hot weather mix, but it can also occur in normal temperatures. This type of heat stroke typically affects young, healthy adults.
What does heat stroke feel like?
Heat stroke involves physical symptoms like nausea, vomiting and dizziness. But it can also cause more than physical discomfort. You may feel confused or have trouble thinking clearly. Others may notice you’re not acting like your usual self. That’s because heat stroke (unlike milder forms of heat illness) affects your brain function, causing changes in your thinking and behavior.
What causes heat stroke?
Heat stroke happens when excess heat overwhelms your body’s built-in system for cooling itself. Excess heat can come from:
- Outside your body. This is environmental heat. Think of the hot, humid air that surrounds you on a summer’s day or the warm, stuffy air in an enclosed room.
- Inside your body. This is heat your metabolism generates during physical activity. It’s what you might call internal body heat.
These can occur at the same time. For example, you might go for a run on a hot day.
Normally, your body can get rid of excess heat — primarily through sweating — and restore a normal body temperature. When sweat evaporates from your skin, it cools your skin and the tissues underneath. This process is vital to thermoregulation, or your body’s ability to maintain a constant internal temperature that’s not too hot or too cold.
But if the air around you is very hot or your metabolism generates lots of heat, your body may struggle to keep up. Just like extreme heat can strain your home’s A/C unit, it can also overtax your body’s natural cooling system, leading to heat stroke.
Why is heatstroke an emergency?
Heatstroke can lead to permanent disability and death. It may trigger sudden events such as a heart attack or stroke and can worsen existing medical conditions.
Heatstroke needs immediate first aid to lower your body temperature as quickly as possible.
Why might I get heatstroke?
Heatstroke happens after prolonged exposure to heat. It can occur when your body absorbs more heat than it can get rid of by sweating. Excessive sweating can also lead to dehydration if you are not drinking enough water to replace the fluid loss.
Your body will also try to cool down by redirecting blood flow to the skin, which means that your heart must work harder. This may lead to heart problems, especially if you have a heart condition.
You can get heatstroke indoors or outdoors. You can get heatstroke if you work or exercise in hot conditions without good air flow and if you don't drink enough water.
Am I at risk of heatstroke?
You are at higher risk if you have certain health issues, for example, if you:
- Are affected by a chronic health condition or an infection
- Take medicines or drugs that cause dryness or make you sweat less
- Live with a chronic disease that affects how you sweat
- Need to restrict your fluid intake (for example, due to a medical condition or fasting) and are unable to drink when you're thirsty
Some groups of people are also at higher risk, for example, people who are:
- Very old or very young
- Pregnant or breastfeeding
- Living with overweight or obesity
- Not physically fit
- Homeless or isolated
Your work environment or living situation may put you at a higher risk of heatstroke. You are also more likely to suffer heat illnesses if you wear heavy, dark clothing on hot days.
Heatstroke First Aid
If you think that someone has heatstroke, immediately call 911 or take the person to a hospital. Any delay in seeking medical help can be fatal.
While waiting for the paramedics to arrive, begin first aid. Move the person to an air-conditioned environment or at least a cool, shady area, and remove any unnecessary clothing.
If possible, take the person's core body temperature and start first aid to cool it to 101-102 F. (If no thermometers are available, don't hesitate to begin first aid.)
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| Try to stay healthy in the heat |
Try these cooling strategies:
- Fan air over the person while wetting their skin with water from a sponge or garden hose.
- Apply ice packs to their armpits, groin, neck, and back.
- Put the person in a shower or tub of cool water.
- If the person loses consciousness and stops breathing, start cardiopulmonary resuscitation (CPR).
Heatstroke Prevention
Can heat stroke be prevented?
Yes, it’s often possible to prevent heat stroke. This can be harder to do if you have certain risk factors, but a little planning can go a long way. Here are some suggestions:
- Keep your home cool. Use fans and/or air conditioning. When the temperature is very high — especially above 99 degrees Fahrenheit (37.2 degrees Celsius) — fans won’t be enough.
- Develop a plan for hot days. If your home isn’t cool enough, identify places where you can go to cool down. These include community centers, shopping malls, movie theaters and loved ones’ homes.
- Stay hydrated. Drink plenty of water before, during and after physical activity in the heat. Make sure you also take in electrolytes — for example, by adding electrolyte powders or tablets to your water. It’s important to stay hydrated even if you’re taking it easy, too. Your healthcare provider can advise you on how much water to drink to support your body’s needs.
- Avoid or limit heat exposure. Try to schedule workouts at cooler times of the day (like early morning). On hot days, opt for an indoor workout in air conditioning. If you must exert yourself in the heat — for example, for work — talk to your employer about scheduled breaks and ways to lower the risk of heat-related illness.
- Acclimatize. This is a fancy word that simply means giving your body time to adjust to the heat. A coach or trainer can help you develop a plan that’s right for you. In general, you’ll start with shorter workouts in the heat and gradually make them longer and more intense.
Heatstroke Risk Factors
Heatstroke is most likely to affect older people who live in apartments or homes that don't have air conditioning or good airflow. Other high-risk groups include people of any age who don't drink enough water, have chronic diseases, or drink too much alcohol.
Heatstroke is strongly related to the heat index, which is a measurement of how hot you feel when relative humidity and air temperature are combined. A relative humidity of 60% or more slows sweat evaporation, making it harder for your body to cool itself.
The risk of heat-related illness dramatically increases when the heat index climbs to 90 degrees or more. So it's important, especially during heat waves, to pay attention to the reported heat index. Also, remember that exposure to full sunshine can increase the reported heat index by 15 degrees.
If you live in an urban area, you may be at a higher risk for heatstroke during a prolonged heat wave, particularly if there is stagnant air and poor air quality. In what is known as the "heat island effect," asphalt and concrete store heat during the day and only gradually release it at night, resulting in higher nighttime temperatures.
Other risk factors associated with heat-related illness include:
Age. Infants and children up to age 4 and adults over age 65 are particularly vulnerable because they adjust to heat more slowly than other people.
Health conditions. These include heart, lung, or kidney disease, obesity or underweight, high blood pressure, diabetes, mental illness, sickle cell trait, alcoholism, sunburn, and any conditions that cause fever.
Medications. These include antihistamines, diet pills, diuretics, sedatives, tranquilizers, stimulants, seizure medications (anticonvulsants), heart and blood pressure medications such as beta-blockers and vasoconstrictors, and medications for psychiatric illnesses such as antidepressants and antipsychotics. Illegal drugs such as cocaine and methamphetamine also are associated with an increased risk of heatstroke.
Check with your doctor to see if your health conditions and medications are likely to affect your ability to deal with extreme heat and humidity.
When to see a doctor
If you think a person may be experiencing heatstroke, seek immediate medical help. Call 911 or your local emergency services number.
Take immediate action to cool the person with heatstroke while waiting for emergency treatment.
- Get the person into shade or indoors.
- Remove excess clothing.
- Cool the person with whatever means available — put in a cool tub of water or a cool shower, spray with a garden hose, sponge with cool water, fan while misting with cool water, or place ice packs or cold, wet towels on the person's head, neck, armpits and groin.
Diagnosis
Healthcare professionals can often diagnose heatstroke without testing. However, laboratory tests can confirm the diagnosis, rule out other causes for symptoms and find out if there is any organ damage. These tests include:
- Rectal temperature to check core body temperature. A rectal temperature is the most accurate way of determining core body temperature and is more accurate than mouth or forehead temperatures.
- A blood test to check blood sodium and potassium and the content of gases in blood to see if there's been damage to the central nervous system.
- A urine test to check the color of urine because it's usually darker if someone has a heat-related condition. A urine test also checks kidney function, which can be affected by heatstroke.
- Muscle damage tests to check for serious damage to the muscle tissue, known as rhabdomyolysis.
- X-rays and other imaging tests to check for damage to the internal organs.
Treatment
Heatstroke treatment centers on cooling the body to a standard temperature to prevent or reduce damage to the brain and vital organs. To do this, a healthcare professional may take these steps:
- Immersion in cold water. A bath of cold or ice water has been proved to be the most effective way of quickly lowering the core body temperature. The quicker someone with heatstroke receives cold water immersion, the less risk of death and organ damage.
- Use evaporation cooling techniques. If cold water immersion is not available, healthcare professionals may try to lower body temperature using an evaporation method. Cool water is misted on the body while warm air is fanned over the person, causing the water to evaporate and cool the skin.
- Packing with ice and cooling blankets. Another method is to wrap a person in a special cooling blanket and apply ice packs to the groin, neck, back and armpits to lower temperature.
- Give medicines to stop shivering. If treatments to lower body temperature make you shiver, your doctor may give you a muscle relaxant, such as a benzodiazepine. Shivering increases your body temperature, making treatment less effective.
Heatstroke Recovery
Recovering from heatstroke can take about a week or longer. It depends on your age, the severity of your heatstroke, and any medical conditions you may have. Try to avoid hot weather and heavy exercise until your doctor tells you that it's safe to resume your normal activities.
Takeaways
Heatstroke is a medical emergency that requires immediate treatment. Call 911 if you or someone you're with is showing signs of the illness, including headache, muscle weakness, dizziness, confusion, nausea and vomiting, and rapid breathing and heart rate. Heatstroke can be prevented by avoiding outdoor activity in hot weather, drinking plenty of fluids, staying in the shade, wearing sunscreen, and wearing light, breathable clothing.
Heatstroke FAQs
Can heatstroke be treated at home?
Heatstroke is a medical emergency that cannot be treated at home. Call 911 if you think you or someone else has heatstroke.
What food items can prevent heatstroke in summer?
Staying hydrated can help prevent heatstroke. Drinking plenty of water is key, but you can also eat water-rich foods to get the hydration and minerals your body needs. Some good foods include watermelon, cucumber, celery, and oranges.
How do you diagnose a heat stroke?
Diagnosing heat stroke involves recognizing symptoms like high body temperature, confusion, rapid pulse, hot, dry skin, and unconsciousness. Immediate medical help is crucial.
What are the symptoms and treatments to heat stroke?
Symptoms of heat stroke include high fever, confusion, rapid pulse, and dry skin. Treatment involves cooling the body, hydration, and immediate medical care.
What is the first aid treatment for heat stroke?
First aid for heat stroke includes cooling the person with ice packs, water, or a cool bath, and seeking emergency medical help immediately.
