Has normal body temperature changed from 98.6F?

Health & Wellness

Q: I thought a normal temperature was 98.6° F (37° C). Has that changed? If it has, what is a fever?

A: Yes. The change is proposed by many in the medical community.

New research reveals that the average adult body temperature has dropped 1 degree Fahrenheit since the standard temperature was established in the mid-1800’s. Although, a fever is still considered to be 100.4º F (38º C) for an adult with illness.

General medicine suggests that the average temperature of a healthy adult is 98.6° F (37° C). This standard was established by a German doctor, Carl Wunderlich, after he measured the armpit temperatures of 25,000 people. In his 1871 text, he reviews how temperatures fluctuate in illness. He determined that the average “suspicious” temperature associated with illness was 100.4º F or 38º C (p. 60). Though any temperature above a person’s usual body temperature can be considered a fever, clinicians have used Dr. Wunderlich’s standards until now.

The fact is, people are cooling down. More recent research shows a steady decline of adult body temperature by abut 1º F since Dr. Wunderlich’s text was written. An average temperature of 97.6 was found in multiple studies since 1935 to 2014.

Some scientists currently suggest that 2º F above your baseline temperature is a more accurate measure of fever for an individual. Many things influence body temperature like your immune system, time of day (relatively higher at night), some chronic illnesses, and acute conditions of hyper/hypothermia. However weight, age, gender and the type of method used to measure have no bearing on the cooler temperatures noted in more modern studies. So what accounts for the change?

There are a few factors speculated for the drop in temperature:

-In general, people have a lower metabolism than in the 19th century
-Fewer people are suffering infectious illnesses with low-grade fever
-Thermometers are better
-Chronic use of fever reducing medications for other preventative measures and pain

Whatever the standard, the symptoms of a fever are the same. We all know what it feels like when we think we have a fever. Symptoms of a fever include:

-Elevated temperature (above 100.4°, 38º C).
-Chills, shivering, shaking.
-Body aches and headaches.
-Fatigue (tiredness).
-Intermittent or constant sweating
-Flushed complexion or hot skin

Always check your temperature with a thermometer if you suspect a febrile illness. What you feel with the back of your hand to your forehead is of little use to your clinician when you call late at night.

If you have an elevated temperature drinking plenty of liquids and resting are best. However, if your temperature exceeds 102º F for more than an hour after taking a fever reducer, call your clinician immediately. Remember that fever, cough, and shortness of breath are the three major symptoms of COVID-19. If you think that you have been exposed to someone, seek health care without delay.

Dr. Wunderlich’s textbook:
Wunderlich CA, Seguin E. Medical thermometry and human temperature. New York: : William Wood & Company 1871. https://collections.nlm.nih.gov/…/nlm:nlmuid-32731270R-bk

Redefining temperature

Literature review of 20 research studies from 1935-1999

Large temperature study of +35,000 subjects from 2009-2014

Link to Original FB Post