Hyperthermia: Symptoms, Types, Causes, Treatments and Risk Factors

It refers to a group of conditions associated with heat, characterized by an abnormally high body temperature, in other words, the opposite of hypothermia.

The condition occurs when the body’s heat regulation system is overwhelmed by external factors, which causes a person’s internal temperature to rise.

Hyperthermia is considered separate from the conditions in which the internal sources of the body, such as infection, problems with heat regulation, and adverse drug reactions or overdose, cause a high body temperature.

In humans, core body temperature ranges from 95.9 ° F to 99.5 ° F during the day, or 35.5 ° C to 37.5 ° C. In contrast, people with some hyperthermia have a body temperature of more than 100.4 ° F. (38 ° C).

Fast facts about hyperthermia:

  • Severe hyperthermia is defined as a body temperature of more than 104 ° F (40 ° C).
  • Heat exhaustion is one of the most challenging stages of hyperthermia.
  • Any activity that involves exercise in warm and humid environments increases the risk of this condition.

What are the symptoms?

Hyperthermia is a group of conditions where the body becomes too hot and can not regulate its temperature.

The symptoms of hyperthermia depend on the stage reached or how much the body overheats. The signs of overheating can develop very quickly or over hours or days.


As the body tries to cool off sweating, sweat carries water and essential salts called electrolytes that cause dehydration.

Mild dehydration tends to cause minor symptoms, such as headache and muscle cramps.

However, severe dehydration can strip the body of its ability to cool. Without treatment, this can lead to dangerously high body temperatures and life-threatening conditions, including organ failure and death.


Fatigue and heat cramps

This stage of hyperthermia causes:

  • Excessive sweating
  • Red or red skin
  • Muscle cramps, spasms, and pain.
  • Headache or slight dizziness
  • Nausea.

Heat exhaustion

Heat exhaustion, if left untreated, can cause a heat stroke, which is a life-threatening condition.

Symptoms of heat exhaustion include:

  • Cold skin, pale and moist.
  • Extreme sweating.
  • Fast but weak pulse.
  • Nausea, vomiting, and diarrhea.
  • Headache.
  • Muscle cramps.
  • Exhaustion.
  • Weakness.
  • But intense.
  • Dizziness.
  • Less frequent urination and dark urine.
  • Difficulty paying attention or concentrating.
  • Mild swelling of the feet and ankles or fingers and hands.
  • Fainting or temporary loss of consciousness.


Sunstroke can cause dangerous complications without treatment, especially in young children, those whose immune system is compromised, and people over 65 years.

Hyperthermia is also more likely to cause complications in people with heat, heart, and blood pressure conditions.

With a heat stroke, the body temperature is over 103 ° F to 104 ° F, depending on a person’s average normal body temperature.

The temperature and many other early signs of insolation are the same as heat exhaustion. Symptoms of heatstroke include:

  • Fast, strong pulse, or feeble pulse.
  • Rapid and deep breathing.
  • Reduced sweating
  • Warm, red, wet, or dry skin.
  • Nausea.
  • Headache.
  • Dizziness.
  • Confusion.
  • Disorientation.
  • Blurry vision.
  • Irritability or mood swings
  • Lack of coordination.
  • Faint or losing consciousness

The symptoms of a severe heat stroke include:

  • Seizure.
  • Organ failure.
  • Coma.
  • Death.

Another condition that can occur with a severe heat stroke is rhabdomyolysis. This is when a protein released from damaged skeletal muscle cells causes kidney damage.

What causes hyperthermia?

Hyperthermia occurs when the body can no longer release enough heat to maintain an average temperature.

The body has different adaptation mechanisms to eliminate excess body heat, mainly breathing, sweating, and increased blood flow to the skin’s surface.

But when the outside environment is warmer than the inside of the body, the outside air is too hot or humid to passively accept the heat of the skin and evaporate the sweat, making it difficult for the body to release its heat.

As overheating progress, the body loses more and more moisture and electrolytes, lowering blood pressure and limiting sweating.


  • Cooling with a cloth with cold water or a fan to cool the skin will benefit those with mild to moderate hyperthermia.
  • A person should immediately stop doing and move to a calm, shady place with good airflow if they suspect hyperthermia.
  • People should seek medical attention if heat cramps last more than an hour after resting in a cool place.
  • You should also seek medical attention for general symptoms that do not improve within 30 minutes of rest and care.

Additional tips for treating mild to moderate hyperthermia include:

  • Drink cold water or an electrolyte drink.
  • Loosen or remove excess clothing.
  • Lie down and try to relax.
  • Take a bath or a cold shower.
  • Place a cool, damp cloth on your forehead.
  • Put the wrists under cold water for 60 seconds.
  • Do not resume activity until the symptoms disappear.
  • Place ice packs or compresses under the arms and groin.
  • Use a fan to cool the skin.

If heat stroke is suspected or symptoms persist, 911 should be called immediately, or the individual should be taken to the emergency room.

Another person will have to help if the individual with heat stroke is unconscious or very disoriented.

Guidelines for dealing with heat stroke include:

  • Move to a calm, shaded, well-ventilated area.
  • Go to bed.
  • Loosen or remove excess clothing.
  • Do not eat or drink anything unless you are fully aware.
  • Use cold, damp cloths on the skin.

Once in the hospital, doctors can administer intravenous fluids that contain electrolytes and possibly refrigerated fluids.

People will be monitored closely until the symptoms resolve and their body temperature returns to a safe level, taking several hours.

Additional medications and emergency treatments may be needed for severe or complicated cases of heatstroke, even if there has been an organ failure, seizures, or other medical conditions.

Severe cases of hyperthermia often require several days of hospitalization and monitoring until a person is fully recovered.

Risk factor’s

Hyperthermia often occurs during physical exercise or in a warm or humid environment.

During exercise, blood pressure increases to supply more oxygen to the tissues that work, which increases the body temperature and the amount of work the body must do to maintain a stable temperature.

When combined with other factors, such as warm weather that also increases body temperature and reduces their ability to release heat, it is not surprising that exercise can increase the likelihood of overheating.

Although it is less common, hyperthermia can also occur while someone is resting, especially during extreme heatwaves. Those with certain medications, diets, and some medical conditions may also be affected by hyperthermia even when they are at rest.

In addition to a person who is less than 16 years of age or older than 65, the risk factors for hyperthermia include:

  • Immune conditions
  • Heart disease.
  • Blood pressure or circulation conditions.
  • Lung, kidney, and liver diseases.
  • Dehydration, especially chronic dehydration.
  • Metabolic conditions
  • Diabetes.
  • Sweat glands or sweating.
  • Obesity.
  • Excessive alcohol consumption.
  • Smoke.
  • Being underweight
  • Gastroenteritis.
  • Diuretic medications, usually for high blood pressure or conditions, such as glaucoma and edema.
  • The central nervous system’s medications include antihistamines, antipsychotics, and beta-blockers.
  • A diet low in sodium or a low salt diet.
  • Illicit use of drugs, particularly synthetic marijuana.

Activities that lead to a higher risk of hyperthermia

Everyday activities that increase the risk of hyperthermia include:

  • Those who participate in marathons or long-distance races run the risk of hyperthermia.
  • Football.
  • Rugby.
  • Use of saunas and jacuzzis.
  • Hiking.
  • Cycling.

Several jobs or types of work also increase the risk of hyperthermia. Common occupations or work associated with an increased risk of hyperthermia include:

  • Military.
  • Building.
  • Manufacturing.
  • Emergency, including firefighters, police, and 911 medical teams.
  • Farming.
  • Forestry.
  • Surveyors.
  • Conservationists and field biologists.
  • Park staff and wildlife officers.

These occupations carry a risk because they expose people to extreme heat or involve protective equipment, such as fire-fighting equipment that severely limits airflow and the body’s ability to cool down.