Why Do We Get Fevers?

How the Body Temperature Rises and Why

When should you worry about a fever?. Flynn Larsen/Taxi/Getty Images

So many people worry about fevers unnecessarily. The myths and concerns over the body temperature going up and causing permanent damage are largely unfounded but people continue to worry because most don't know why it happens or what it means. Lucky for you, we're going to clear up the confusion.

Why Does the Body Temperature Rise?

A fever is a term we use to describe an elevated body temperature. A normal temperature is considered 98.6 degrees F or 37 degrees C.

However, "normal" can vary from person to person. Most healthcare providers consider anything between 97 and 100.3 degrees F to be normal. If the temperature is higher than 100.3 F, it's a fever.

It's important to understand that fevers are not illnesses. A fever is a symptom. It is the body's response to another issue. Things that can cause fevers include:

  • Infections (bacterial, viral, fungal, etc)
  • Overdressing (most common in infants and young children)
  • Medications
  • Immunizations
  • Cancers
  • Autoimmune diseases
  • Heat exhaustion (hyperthermia)

Researchers believe the body temperature rises in response to infections in an effort to kill the invading germs. Most bacteria and viruses live well and multiply at the normal body temperature of 98.6 but cannot survive higher temperatures. The hypothalamus (which is located in the brain) acts like a thermostat and turns up the body temperature in response to an invasion by those germs.

It's one of our natural defenses against infection.

Treatment for Fevers

If your fever is caused by an illness (most are), then the most important step is trying to figure out which illness you have and how to treat it. Once you have done that or you feel confident that you aren't dealing with anything serious, there are a few things you can do to bring your temperature down.

Take Over the Counter Fever Reducers

If you feel miserable when you have a fever, taking over the counter fever reducers may help. They don't always bring the temperature down to normal but that is okay as long as they help you feel better.

**Children under the age of 18 should never take aspirin unless specifically instructed to do so by their Pediatrician. Aspirin use in kids has been linked to a serious illness called Reye's syndrome.

Try Reducing the Fever Without Medications

These tips are generally not as effective as taking fever reducing medications but may be helpful if the fever isn't making you (or your child) feel very bad.

Removing extra layers, taking a lukewarm bath and putting cool cloths or packs under the arms and on the forehead can all help bring the temperature down temporarily.

Aren't High Fevers Dangerous?

No. Believe it or not, a fever is not going to hurt you or your child. Except in rare circumstances when a person already has some type of neurological damage or condition, the body temperature will not go so high that it will cause any type of harm.

Children can run temperatures of 104 or even 105 and be okay.

Some children experience febrile seizures when they get fevers – particularly above 102 degrees F. Although these seizures are generally not dangerous and do not cause permanent damage, they are frightening for parents and should be evaluated by a doctor right away.

When it comes to kids, keep these things in mind:

If your child is under 3 months old and has a temperature higher than 100.3F, seek medical attention. Infants that young do not often develop fevers unless they have a serious illness.

If your child is between 3 months and 3 years, contact your health care provider if she has a temperature higher than 102.2F. While the fever is not going to hurt her, it could be an indication that there is an infection or illness that needs to be treated.

If your child is older than 3 years old and has a fever, the number on the thermometer is not important but her behavior and other symptoms are. If she doesn't want to play, smile or drink much, even after taking a fever reducer, then you need to contact her health care provider.

Fevers are scary to many people. Hopefully, this information clears up some of the misconceptions you or others have about them. If you have concerns about your health, this information should be used as a guide only and not as medical advice. Contact your health care provider for specific advice about your health.


"Fevers" Health Topics 26 Feb 14. MedlinePlus. US National Library of Medicine. National Institutes of Health. Department of Health and Human Services.

"Fever and Taking Your Child's Temperature" Your Kid's Body 2014. KidsHealth from Nemours. The Nemours Foundation. 

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