Dear Dr. Peg: If your usual body temperature is below the normal 98.6 degrees, do you experience a fever at lower temperatures than normal as well?
- Mr. Cool
Dear Mr. Cool,
As you clearly realize, normal body temperature can differ from person to person. The textbook figure of 98.6 degrees Fahrenheit is an average. In real life, people vary. Some run cool; others run warm. Not only that, but normal body temperature changes throughout the day. We tend to be coolest early in the morning and warmest in the evening.
Body temperature can also be increased by physical activity, strong emotion, eating, heavy clothing, high room temperature or outside temperature, high humidity or medication. Women's temperatures can go up and down about a degree due to their menstrual cycle.
This is not one of those sciences that can be pinned down to the nearest decimal point, although most healthy people fall somewhere between 97 and 99 degrees.
That being said, there are some guidelines and limits. Below 95 is dangerously low, and above 104 can be dangerously high.
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A fever has been defined as either higher than 99.4 or 1.5 degrees above your normal level, depending on who you ask.
To complicate things further, there are several ways and places on the body to measure your temperature. The most accurate reading comes from a rectal thermometer. Lucky for you, we don't do that here. In the Student Health and Counseling clinic, we use an infrared sensor that goes into your ear canal. Home thermometers are usually placed in the mouth. Ear and mouth readings are generally about a degree lower than rectal readings. The numbers in this article refer to ear or mouth temperatures. Sometimes temperatures are taken by placing a thermometer in the armpit for a few minutes, but that is not very accurate.
Basically, a fever is an increase in body temperature. It usually happens in response to an infection by a virus or bacteria. A fever is part of your body's immune response. It serves a purpose. For example, many viruses prefer to live at lower temperatures. When your brain turns up the heat, they move out. In addition, higher temperature primes our immune system to make more immune cells, help them move faster and work more efficiently. Fever can get you over an infection quicker.
Does that mean you should leave a fever alone? It depends. If you're really miserable, especially if you can't sleep because of your fever, go ahead and bring it down. Toss off the blankets, dress lightly or try a cool bath. If that doesn't work, take acetaminophen (generic form of Tylenol) or ibuprofen.
If the fever is very high (over 103) you should bring it down as well. A very high fever can essentially bake your brain, causing hallucinations, irritability and even seizures.
Fever can be a normal part of common illness and doesn't necessarily mean you have to run to the clinic or call your doctor. But if the fever is more than 103, lasts more than three days or comes along with any of the following symptoms, do contact medical professionals right away: severe headache, severe swelling of throat, rash getting quickly worse, eye sensitivity to bright light, stiff neck or pain when bending head forward, mental confusion, persistent vomiting, difficulty breathing or chest pain, extreme listlessness or irritability, abdominal pain or pain with urinating, any other unexplained signs or symptoms.
Any questions? Contact Student Health and Counseling at 277-3136.
Peggy Spencer, M.D., has been a UNM Student Health physician for 17 years and a Daily Lobo columnist for three years. She is co-author of the book 50 Ways to Leave Your 40s, released in March. E-mail your questions to her directly at Pspencer@unm.edu. All questions will be considered, and all questioners will remain anonymous. This column has general health information only and cannot replace a visit to a health care provider.
