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'What Is Considered a Fever?'

woman wrapped in blanket with tissue taking temp
By Elizabeth Hanes, BSN, RNOctober 30, 2020

One of the most common symptoms of illness -- whether it’s COVID-19 or the flu -- is fever. But what, exactly, is considered “a fever”?

For most adults, normal body temperature ranges from around 97 degrees Fahrenheit to nearly 99 degrees. A temperature reading between 99 and 100.3 often is called a “low-grade” fever. This means your temperature is elevated, which could indicate you’re ill, but could also be explained by other factors -- activities like a vigorous workout or sitting in the sun could cause this kind of subtle change in body temperature. In any case, it’s typically nothing to be too concerned about.

A body temperature reading above 100.4 F is considered a true fever in adults. For a fever between 100.4 and 103 F, you can take a fever-reducing product and apply cool compresses to your brow to relieve the discomfort of feeling so hot.

In adults, a fever above 103 F requires medical attention. Call your doctor’s office right away for instructions about what to do for a very high fever.

The definition of fever in infants and children is more complex. It depends on the age of the child and involves several different temperature ranges. In general, call your doctor for any fever in a baby under 6 months of age or for fever above 102 F in older children.

While we’re on the subject, understand that fever is a natural occurrence and not necessarily any cause for alarm. When the immune system ramps up to fight an infection, it causes your body’s temperature to rise -- just the way a car’s engine goes from cool to warm as it starts to run. So, you shouldn’t panic if you develop a fever. It mainly means your immune system is working properly.

And because fever is a normal part of your immune system’s process for fighting infection, you might not need to treat it. In fact, taking fever-reducing products to bring down your body temperature can allow a germ to survive better inside your body (because a lot of them can’t tolerate a hot environment). Knowing this, whenever I develop a fever, I usually skip the fever-reducing medications, go to bed, and allow my body to take care of business (as long as my fever is under 103).

That said, fevers can be very uncomfortable, so if you feel the need, take an over-the-counter product to treat your fever, body aches, and other symptoms until the illness passes and your temperature returns to normal. If your fever lasts for more than 3 days or if you’re experiencing other symptoms, call your doctor.




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