What happens if your internal body temperature is high?

While a normal body temperature is around 98.6°F (37°C), sustained temperatures above 104°F (40°C) are considered a medical emergency. Understanding what happens if your internal body temperature is high is crucial for your health and safety, as it can lead to serious complications and even death.

Quick Summary

When internal body temperature rises dangerously high, the body's cooling mechanisms can fail, leading to hyperthermia conditions like heat exhaustion and the life-threatening heatstroke. This can cause vital organ damage, confusion, and circulatory strain if not addressed with immediate and appropriate cooling measures.

Key Points

• Know the difference: Hyperthermia is an uncontrolled temperature rise from external heat, while a fever is a controlled response to infection.

• Recognize the stages: Heat-related illnesses progress from mild heat cramps to the severe, life-threatening heatstroke.

• Watch for mental changes: Confusion, slurred speech, or seizures are signs of severe heatstroke and require immediate emergency care.

• Act quickly: For heat exhaustion, move to a cool area and hydrate; for heatstroke, call 911 and begin cooling the person immediately.

• Prioritize prevention: Staying hydrated, avoiding extreme heat, and pacing yourself during exercise are the best ways to avoid hyperthermia.

• Damage is possible: Untreated, a very high internal temperature can cause irreversible damage to the brain, heart, and kidneys.

Understanding the body's thermoregulation

Your body's ability to maintain a stable core temperature is called thermoregulation, a complex process controlled by a part of the brain called the hypothalamus. When you get too hot, your hypothalamus triggers several cooling responses. Sweating is one of the most effective, as the evaporation of moisture from your skin pulls heat away from your body. Your blood vessels also widen (vasodilation), directing more blood toward your skin's surface to help dissipate heat. Problems arise when these mechanisms are overwhelmed, either by excessive external heat, strenuous physical activity, or an underlying medical condition. This can lead to a condition known as hyperthermia, where the body's heat-regulating system malfunctions and the core temperature rises uncontrollably.

Hyperthermia vs. Fever: A key distinction

It's important to differentiate between hyperthermia and fever, as they have different causes and require different treatments.

Fever

• Cause: Fever is a controlled increase in your body's temperature set-point, triggered by your immune system to fight off an infection.
• Mechanism: The hypothalamus raises the internal temperature, making it a hostile environment for viruses and bacteria.
• Treatment: Fevers are often treated with antipyretic medications like ibuprofen or acetaminophen to bring the temperature down, but may not be necessary for low-grade fevers.

Hyperthermia

• Cause: Hyperthermia is an uncontrolled and dangerous rise in body temperature due to external factors, such as extreme heat and humidity, strenuous exercise, or certain medications.
• Mechanism: The body's cooling system is overwhelmed and cannot regulate temperature, leading to a rapid, uncontrolled temperature spike.
• Treatment: Medications are ineffective against hyperthermia, which requires immediate physical cooling and often emergency medical care.

Stages of heat-related illness

Hyperthermia presents in a spectrum of severity, from mild heat cramps to the life-threatening heatstroke.

Heat Cramps

These are the mildest form of heat illness and typically occur during heavy sweating and exertion. They manifest as painful, involuntary muscle spasms, often in the legs, abdomen, or arms, and are caused by the loss of salts and fluids.

Heat Exhaustion

This is a more serious condition that can develop after hours or days of exposure to high temperatures.

Symptoms of heat exhaustion include:

• Heavy sweating
• Paleness or clammy skin
• Nausea or vomiting
• Dizziness or fainting
• Headache
• Weak, rapid pulse
• Muscle cramps
• Elevated body temperature (but below 104°F)

Heatstroke

Heatstroke is the most severe and life-threatening form of hyperthermia, requiring immediate emergency medical attention. This occurs when the body's temperature regulation system completely fails.

Warning signs of heatstroke include:

• Core body temperature of 104°F (40°C) or higher
• Altered mental state, such as confusion, slurred speech, or delirium
• Loss of consciousness
• Hot, red, dry skin (though sweating can still be present in exertional heatstroke)
• Seizures
• Rapid, strong pulse
• Rapid, shallow breathing

Potential damage to vital organs

If left untreated, a high internal body temperature can cause significant damage to vital organs.

The cardiovascular system

As the body tries to cool itself, it directs blood flow to the skin, forcing the heart to work harder to pump blood. This increased strain can lead to a racing heart rate and, in severe cases, cause heart failure, especially in individuals with pre-existing heart conditions.

The nervous system

Excessive heat can severely disrupt brain function, causing swelling and permanent damage. This is why altered mental states, seizures, and unconsciousness are hallmarks of heatstroke.

The kidneys

Severe dehydration caused by excessive sweating and the strain on the circulatory system can lead to acute kidney failure. Rhabdomyolysis, the breakdown of muscle tissue seen in severe cases, also releases substances that can damage the kidneys.

What to do if your internal body temperature is high

First-aid for heat exhaustion

1. Move to a cool place. Get out of the sun and into a shaded or air-conditioned environment immediately.
2. Lie down and elevate legs. This promotes blood flow to the core.
3. Drink cool fluids. Water or a sports drink to replace electrolytes is best. Avoid alcohol or sugary beverages.
4. Cool the body. Use cool, wet cloths or take a tepid (not cold) shower.
5. Seek medical help if symptoms worsen or don't improve.

Immediate action for heatstroke

Heatstroke is a medical emergency. Call 911 or your local emergency number immediately. While waiting for help, begin cooling the person by:

1. Moving them to a cooler environment.
2. Applying ice packs to the neck, armpits, and groin, or immersing them in cool water if possible.
3. Removing any excess clothing.
4. Do not give them fluids if they are unresponsive or confused, as this can cause them to choke.

Comparison: Heat Exhaustion vs. Heat Stroke

Feature	Heat Exhaustion	Heat Stroke
Body Temperature	Elevated, but typically below 104°F (40°C)	Dangerously high, 104°F (40°C) or higher
Skin Condition	Cool, pale, and clammy with heavy sweating	Hot, red, and dry (sweating mechanisms fail) or can be profuse sweating
Mental State	Confused, irritable, or dizzy	Disoriented, agitated, slurred speech, seizures, unconsciousness
Other Symptoms	Nausea, vomiting, headache, muscle cramps	Nausea, rapid breathing, racing heart rate, throbbing headache
Severity	Serious, but not immediately life-threatening	Medical Emergency; can be fatal if untreated
Treatment	Move to cool area, hydrate, cool cloths	Call 911, rapid body cooling is critical

Prevention is the best medicine

To avoid complications from a high internal body temperature, especially during hot weather or strenuous activity:

• Stay hydrated throughout the day.
• Limit outdoor activity during the hottest parts of the day.
• Wear loose-fitting, light-colored clothing.
• Take frequent breaks in cool, shaded areas.
• Avoid leaving anyone, especially children or the elderly, in a parked car.

For more detailed information on heat-related illnesses and symptoms, consult the resources provided by reputable health organizations like the Mayo Clinic.

Conclusion

While the body is adept at regulating its temperature, external factors and underlying issues can cause it to overheat, leading to a range of hyperthermia-related illnesses. Recognizing the difference between a fever and hyperthermia, and knowing the symptoms of heat exhaustion and heatstroke, is vital for a quick and appropriate response. Prompt action, including moving to a cooler environment and seeking medical attention for severe symptoms, can prevent serious organ damage and save lives. Prioritizing prevention by staying hydrated and cool is the most effective strategy for managing your health in high-heat conditions.

Frequently Asked Questions

At what temperature does a high internal body temperature become dangerous?

A core body temperature of 104°F (40°C) or higher is considered a medical emergency and indicative of heatstroke, a life-threatening condition.

Can high internal body temperature lead to brain damage?

Yes. Sustained, extremely high internal body temperatures can cause swelling of the brain and other vital organs. In severe cases, this can lead to permanent neurological damage or death.

What is the key difference between heatstroke and heat exhaustion?

Heatstroke involves a very high temperature (104°F+) and altered mental state, indicating a failure of the body's cooling system. Heat exhaustion is a less severe illness with an elevated but lower temperature and does not typically involve confusion or unconsciousness.

How can I lower a high internal body temperature quickly?

For heatstroke, immediate cooling is critical. This includes moving to a cooler location, applying ice packs to the neck, armpits, and groin, or immersing the person in cool water while waiting for emergency services to arrive.

Is sweating a reliable sign of whether my body is too hot?

Not always. While sweating is the body's primary cooling mechanism, the most severe cases of heatstroke often involve a failure of this system, resulting in hot, dry skin. In exertional heatstroke, however, heavy sweating may still be present.

Can certain medications affect my body's ability to regulate temperature?

Yes. Certain medications, including some diuretics, antidepressants, and antihistamines, can affect your body's ability to regulate its temperature. It is important to discuss your medications with a doctor, especially if you plan to be in hot environments.

When should I seek medical help for a high temperature?

You should seek immediate medical attention if you or someone you know has a temperature of 104°F or higher, exhibits signs of confusion, loses consciousness, or has seizures. Also, seek help if a fever persists for more than a few days or is accompanied by severe symptoms like stiff neck or difficulty breathing.