Hyperthermia: Symptoms, Treatment, and More (2023)

Hyperthermia vs. hypothermia

You may be familiar with the term hypothermia. This happens when your body’s temperature drops to dangerously low levels. The opposite can also occur. When your temperature climbs too high and threatens your health, it’s known as hyperthermia.

Hyperthermia is actually an umbrella term. It refers to several conditions that can occur when your body’s heat-regulation system can’t handle the heat in your environment.

You’re said to have severe hyperthermia if your body temperature is above 104°F (40°C). By comparison, a body temperature of 95°F (35°C) or lower is considered hypothermic. The average body temperature is 98.6°F (37°C).

Hyperthermia comes in many stages. Heat exhaustion, for example, is a common condition. But others, such as heat syncope, may be less familiar to you. The following is a list of hyperthermic conditions and other heat-related illnesses.

Heat stress

If your body temperature starts to climb and you’re unable to cool yourself through sweating, you’re experiencing heat stress. Heat stress can lead to serious complications, such as heat exhaustion and heat stroke.

In addition to feeling uncomfortably hot, you may also experience:

  • dizziness
  • weakness
  • nausea
  • thirst
  • a headache

If you’re feeling signs of heat stress, get to a cooler area and rest. Start drinking water or other fluids with electrolytes that will help restore hydration. Electrolytes are substances in the body, such as calcium, sodium, and potassium that keep you hydrated. They help regulate your heart rate, nerve function, and muscle health.

If your symptoms worsen, seek medical attention.

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Heat fatigue

If long hours in high heat are causing you physical discomfort and psychological stress, you may be dealing with heat fatigue. People who aren’t used to extremely hot weather or hot working conditions are especially vulnerable to heat fatigue.

In addition to simply feeling hot, thirsty, and tired, you may have difficulty concentrating on your work. You may even lose coordination.

If you notice a strain on your physical and mental well-being, get out of the heat and cool down with fluids.

Slowly adjusting to working or exercising in a hot environment can help prevent future heat fatigue.

Heat syncope

Syncope, also known as fainting, occurs when your blood pressure drops and blood flow to the brain is temporarily reduced.

It tends to happen if you’ve been exerting yourself in a hot environment. If you take a beta-blocker to lower your blood pressure, you’re at greater risk for heat syncope.

Fainting is often preceded by dizziness or lightheadedness. You may feel close to fainting, but if you relax and cool down quickly, you may prevent actually losing consciousness. Putting your legs up can help.

As with other heat-related illnesses, rehydrating is key. Any fluid will do, but water or electrolyte-filled sports drinks are best.

Learn more: What to expect during and after a syncopal episode »

Heat cramps

Heat cramps usually follow intense exertion or exercise in the heat. They’re usually the result of an electrolyte imbalance and are typically felt in the abdomen, leg, or arm muscles.

To help relieve heat cramps, rest in a cool place, and be sure to replenish the fluids and electrolytes that are lost when you sweat.

Heat edema

Heat edema can occur if you stand or sit for a long time in the heat and are not used to being in warmer temperatures. This can cause your hands, lower legs, or ankles to swell.

(Video) MALIGNANT HYPERTHERMIA, Causes, Signs and Symptoms, Diagnosis and Treatment.

This swelling is from fluid buildup in your extremities. This is possibly related to a response involving the aldosterone-stimulated reabsorption of sodium into the blood through the kidneys.

Usually heat edema spontaneously subsides over time once you become used to the warm environment. Cooling down and putting your feet up will also help, as will staying hydrated with adequate water and electrolyte intake.

Heat rash

Sometimes, being active in the heat for prolonged periods of time can cause red pimple-like bumps to appear on the skin. This usually develops underneath clothing that has become soaked with sweat.

Heat rash typically disappears on its own after you cool down or change clothes.

However, infection is possible if the skin isn’t allowed to cool soon after the rash has appeared.

Learn more: Types of heat rash »

Heat exhaustion

This is one of the most serious stages of hyperthermia. Heat exhaustion occurs when your body can’t cool itself any more.

In addition to sweating profusely, you may experience:

  • dizziness
  • weakness
  • thirst
  • coordination issues
  • trouble concentrating
  • skin that’s cool and clammy
  • rapid pulse

This is the last stage before heat stroke occurs, so it’s important that you rest and rehydrate as soon as you feel symptoms developing.

If you don’t feel your symptoms improving, seek immediate medical attention.

Keep reading: Do you have heat stroke or heat exhaustion? Learn the signs »

Hyperthermia’s most serious stage is heat stroke. It can be fatal. Other heat-related illnesses can lead to heat stroke if they aren’t treated effectively and quickly.

Heat stroke can occur when your body temperature reaches above 104°F (40°C). Fainting is often the first sign.

Other signs and symptoms include:

  • irritability
  • confusion
  • coordination issues
  • flushed skin
  • reduced sweating
  • weak or rapid pulse

When these signs start to emerge, you should:

  • Try to get to a cool location, preferably one with air conditioning.
  • Drink water or electrolyte-filled sports drinks.
  • Take a cool bath or shower to help speed up your recovery.
  • Place ice bags under your arms and around your groin area.

If your symptoms don’t improve when you try cooling off and rehydrating, or you see someone who appears to be having a heat stroke, call your local emergency services immediately.

(Video) What Hypothermia Does To Your Body And Brain

People who work in very hot environments or are exposed to high heat during the course of the job are at high risk for hyperthermia.

Construction workers, farmers, and others who put in long hours outside in the heat should take precautions against hyperthermia. The same is true for firefighters and people who work around large ovens or in indoor spaces that are poorly air-conditioned.

(Video) Hyperthermia - complications & treatment

Certain health conditions can also put you at higher risk for hyperthermia. Certain heart and blood pressure medications, such as diuretics, can reduce your ability to cool down through sweat. If you’re on a low-sodium diet to help manage high blood pressure, you may be quicker to develop hyperthermia.

Children and older adults are at increased risk as well. Many kids play hard in the hot outdoors without taking time to rest, cool off, and stay hydrated. Older adults tend to be less aware of temperatures changes, so they don’t often respond in time if their environment heats up. Older adults who live in a home without fans or air conditioning may also face hyperthermia in extremely hot weather.

Your body’s temperature is regulated by a part of the brain called the hypothalamus. It normally keeps your temperature at around 98.6°F (37°C), with slight variations throughout the day and night.

If your body senses an infection of a virus or bacteria, the hypothalamus may reset your body’s “thermostat” to make your body a hotter, less hospitable host for those infectious agents. In this case, fever occurs as part of the immune system reaction. As the infection disappears, your hypothalamus should reset your temperature back to its normal levels.

With hyperthermia from heat stroke, however, the body is responding to changes in your environment. The body’s natural cooling mechanisms, such as sweating, aren’t enough to overcome the heat of your surroundings. Your temperature climbs in response, causing you to experience some of the symptoms previously described.

Some over-the-counter medications, such as acetaminophen (Tylenol), can help bring down a fever. However, they would be ineffective in treating hyperthermia. Only a change in environment, rehydration, and external cooling efforts (such as cool water or ice packs on the skin) can reverse hyperthermia.

How to prevent hyperthermia

(Video) Hyperthermia - overview of causes

The first step in preventing hyperthermia is recognizing the risks in working or playing in extremely hot conditions. Being in the heat means taking the following precautions:

  • Take cool-down breaks in the shade or in an air-conditioned environment. If you don’t need to be outside in extreme heat, stay indoors.
  • Stay well hydrated. Drink water or drinks containing electrolytes, such as Gatorade or Powerade, every 15 to 20 minutes when you’re active in the heat.
  • Wear lightweight, light-colored clothing when outdoors.
  • If your home isn’t well air-conditioned, consider spending time in an air-conditioned mall, library, or other cool public place during hot spells.

Learn more about heat emergencies »


What is the best treatment for hyperthermia? ›

  • Immerse you in cold water. A bath of cold or ice water has been proved to be the most effective way of quickly lowering your core body temperature. ...
  • Use evaporation cooling techniques. ...
  • Pack you with ice and cooling blankets. ...
  • Give you medications to stop your shivering.
Jun 25, 2022

What are 4 symptoms of hyperthermia? ›

  • High body temperature (103°F or higher)
  • Hot, red, dry, or damp skin.
  • Fast, strong pulse.
  • Headache.
  • Dizziness.
  • Nausea.
  • Confusion.
  • Losing consciousness (passing out)

What are the common signs and symptoms of hyperthermia? ›

  • Confusion, altered mental status, slurred speech.
  • Loss of consciousness (coma)
  • Hot, dry skin or profuse sweating.
  • Seizures.
  • Very high body temperature.
  • Fatal if treatment delayed.

What are 4 treatments for hypothermia? ›

Hypothermia treatment may include warmed IV fluids, heated and humidified oxygen, peritoneal lavage (internal "washing" of the abdominal cavity), and other measures.

What 5 things help in the prevention of hyperthermia? ›

Take frequent breaks. Drink plenty of water. Wear cool clothing. Find a cool shady place to rest.

What is the best treatment or action for hypothermia? ›

Replace wet things with warm, dry coats or blankets. If further warming is needed, do so gradually. For example, apply warm, dry compresses to the center of the body — neck, chest and groin. The CDC says another option is using an electric blanket, if available.

What is the treatment or prevention of hyperthermia? ›

Only a change in environment, rehydration, and external cooling efforts (such as cool water or ice packs on the skin) can reverse hyperthermia.

When is hyperthermia treatment used? ›

Hyperthermia is a treatment that uses very high heat levels to kill small cancer tumors and lower heat levels to enhance the effectiveness of radiation and chemotherapy. It is especially useful for treating previously radiated cancers that have recurred.

How do nurses treat hyperthermia? ›

Provide hypothermia blankets or cooling blankets when necessary. Use cooling blankets that circulate water when the body temperature is needed to be cooled quickly. Set the temperature regulator to 1ºC below the client's current temperature to prevent shivering.

What medications treat hyperthermia? ›

Immediate treatment of malignant hyperthermia includes: Medication. A drug called dantrolene (Dantrium, Revonto, Ryanodex) is used to treat the reaction by stopping the release of calcium into muscles.

What are the 3 stages of hyperthermia in order? ›

Hyperthermia, which is when the body's core temperature begins to rise, occurs in three stages – heat cramps, heat exhaustion, and heat stroke – with the latter being the most serious.

What is hypothermia symptoms? ›

Signs and symptoms of hypothermia include: Shivering. Slurred speech or mumbling. Slow, shallow breathing.

What are the 3 main conditions hyperthermia causes? ›

Causes of hyperthermia include dehydration, use of certain medications, using cocaine and amphetamines or excessive alcohol use. Bodily temperatures greater than 37.5–38.3 °C (99.5-101.0 °F) can be diagnosed as a hyperthermic case.

What disease causes hyperthermia? ›

Malignant hyperthermia is a severe reaction to certain drugs used for anesthesia. This severe reaction typically includes a dangerously high body temperature, rigid muscles or spasms, a rapid heart rate, and other symptoms. Without prompt treatment, the complications caused by malignant hyperthermia can be fatal.

How do you detect hyperthermia? ›

Hyperthermia is confirmed through accurate core body temperature measurement. Core body temperature is most easily measured orally, rectally, or via tympanic membrane measurements.

What is the first stage of treatment for hypothermia? ›

Even the mild stage is an emergency, and a bystander should call 911 if they notice its signs. While waiting on help to arrive, first aid treatment entails getting the individual to a warm, dry place and removing any wet clothing. The underlying cause of hypothermia is prolonged exposure to cold.

Does Tylenol treat hyperthermia? ›

In some cases, anti-seizure or muscle-relaxing medications may be given to control convulsions and shivering. Aspirin and acetaminophen (Tylenol) do not help lower body temperature when a person has heat stroke, and these medications should be avoided if heat stroke is suspected.

What color is skin in hyperthermia? ›

In hyperthermia, hot and dry skin is typical manifestation, and sometimes the skin color turns red. On the other hand, the skin color can become pale in severe febrile convulsion.

What happens to your body during hyperthermia? ›

Heat stroke occurs when someone's body temperature increases significantly (generally above 104 degrees Fahrenheit) and has symptoms such as mental status changes (like confusion or combativeness), strong rapid pulse, lack of sweating, dry flushed skin, faintness, staggering, or coma.

What happens when you get hypothermia? ›

On the road to hypothermia, your body will often go through extremely cold temperatures. This can cause damage to tissues throughout the body. A few of the most common complications associated with hypothermia include: frostbite, or tissue destruction caused by tissues freezing.

What medications cause hypothermia? ›

Hypothermia may be related to drug administration; such medications include beta-blockers, clonidine, meperidine, neuroleptics, and general anesthetic agents. Ethanol, phenothiazines, and sedative-hypnotics also reduce the body's ability to respond to low ambient temperatures.

Who is most at risk of hyperthermia? ›

Those at greatest risk for heat-related illness include infants and children up to four years of age, people 65 years of age and older, people who are overweight, and people who are ill or on certain medications.

How does hyperthermia feel? ›

The body temperature may be over 105 F, a level that damages the brain and other organs. Other symptoms include muscle cramps, fatigue, dizziness, headache, nausea, vomiting, and weakness. The heart rate may be elevated, and the skin is reddened.

How long do the effects of hypothermia last? ›

How long it takes to die from hypothermia depends on several factors, including whether the cold exposure is in air or water, how cold the temperatures are, and the person's underlying health and age. Depending on the conditions, hypothermia can occur within minutes to hours, or slowly over days to weeks.

What are 3 treatment options for frostbite? ›

  • Rewarming of the skin. ...
  • Oral pain medicine. ...
  • Protecting the injury. ...
  • Removal of damaged tissue (debridement). ...
  • Whirlpool therapy or physical therapy. ...
  • Infection-fighting drugs. ...
  • Clot-busting drugs. ...
  • Wound care.
Apr 27, 2022

Are there 4 types of hypothermia? ›

One scale breaks cases into three categories of mild, moderate, and severe hypothermia, with core body temperature readings and symptoms being the differentiators between the three categories.

What are the 4 stages of hypothermia? ›

Each stage can also be differentiated by clinical findings in the field when core temperature reading may not be available.
  • HT I: Mild Hypothermia, 35-32 degrees. ...
  • HT II: Moderate Hypothermia, 32-28 degrees. ...
  • HT III: Severe Hypothermia, 24-28 degrees. ...
  • HT IV: Apparent Death, 15-24 degrees.

What is the first-aid for hypothermia and frostbite? ›

Handle the area gently; never rub the affected area. Warm gently by soaking the affected area in warm. water (100–105 degrees F) until it appears red and feels warm. Loosely bandage the area with dry, sterile dressings.

Is aspirin good for frostbite? ›

Some studies suggest that aspirin or other blood thinner meds may help restore blood flow in body parts with severe frostbite if your doctor gives you them within 24 hours of rewarming.

What is the correct treatment for shock? ›

Seek emergency medical care

Lay the person down and elevate the legs and feet slightly, unless you think this may cause pain or further injury. Keep the person still and don't move him or her unless necessary. Begin CPR if the person shows no signs of life, such as not breathing, coughing or moving.

Which organ controls body temperature? ›

The hypothalamus helps keep the body's internal functions in balance. It helps regulate: Appetite and weight. Body temperature.

What organs does hypothermia affect? ›

Hypothermia causes major dysfunction in vital organs such as the heart, leading to irregular heartbeat; the kidneys, leading to kidney failure; and the brain, leading to mental status changes such as confusion or loss of consciousness. Liver damage, bleeding disorders, and breakdown of muscle tissue can also occur.

What vitamin deficiency causes you to feel cold? ›

Lack of vitamin B12 and iron deficiency can cause anemia and lead you to feel cold.

What happens to body during hypothermia? ›

When exposed to cold temperatures, your body begins to lose heat faster than it's produced. Lengthy exposures will eventually use up your body's stored energy, which leads to lower body temperature. Body temperature that is too low affects the brain, making the victim unable to think clearly or move well.

What happens during hyperthermia? ›

Heat stroke occurs when someone's body temperature increases significantly (generally above 104 degrees Fahrenheit) and has symptoms such as mental status changes (like confusion or combativeness), strong rapid pulse, lack of sweating, dry flushed skin, faintness, staggering, or coma.


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