The Myth of 98.6°F: What’s the Real Human Body Temperature?
For over a century, 98.6°F (or 37°C) has been touted as the gold standard for “normal” human body temperature. Thermometers, medical charts, and even school textbooks have long treated this number as a fixed point of reference. But the truth is, human body temperature isn’t static—and it probably never has been. So where did the 98.6°F figure come from, and why isn’t it entirely accurate?
The Origin of the 98.6°F Standard
The number dates back to 1868, when German physician Carl Reinhold August Wunderlich published a groundbreaking study on body temperature. He measured the armpit temperatures of about 25,000 people using a foot-long mercury thermometer, and he concluded that the average healthy body temperature was 98.6°F.
However, there were a few problems. Wunderlich’s thermometer was likely not as precise as modern instruments, and he took measurements in the armpit, which tends to read lower than oral or rectal temperatures. Plus, he averaged the readings into a single number, even though his own data showed considerable variation.
Despite these issues, 98.6°F was adopted around the world and held up as the “normal” temperature for over 150 years.
What’s the Real Normal?
Recent research shows that the average human body temperature is actually lower than 98.6°F. A 1992 study published in the Journal of the American Medical Association found that the average temperature is closer to 98.2°F (36.8°C). More recent research has suggested it's dropped even more, with some studies showing an average of around 97.9°F (36.6°C).
One 2020 study from Stanford University examined temperature data spanning 150 years and concluded that body temperature in the United States has been steadily decreasing over time. The researchers suggested factors like improved public health, reduced chronic infections, and changes in living conditions (like better climate control in homes) could be playing a role.
Body Temperature Isn’t One-Size-Fits-All
It’s important to know that “normal” body temperature isn’t the same for everyone—and it can vary even within the same person. Here are some factors that influence body temperature:
-
Time of Day: Your temperature is lower in the early morning and tends to peak in the late afternoon or evening.
-
Age: Children typically have slightly higher body temperatures than adults. As people age, their average body temperature may drop slightly.
-
Sex: Women may have slightly higher temperatures than men, especially during ovulation due to hormonal fluctuations.
-
Activity Level: Exercise or physical exertion raises your body temperature.
-
Measurement Method: Oral, rectal, ear, and forehead thermometers can all produce slightly different readings.
So, that 98.6°F number? Think of it more as a rough guide rather than a rule.
What Counts as a Fever, Then?
If 98.6°F isn’t the true normal, does that change how we define a fever?
Not drastically. Most doctors still consider a temperature of 100.4°F (38°C) or higher to be a fever, though what’s considered concerning may depend on symptoms and individual baselines. Some people naturally run cooler or warmer, so context matters.
If you usually sit around 97.5°F, a temp of 99.5°F might mean something’s going on. On the flip side, someone whose average is closer to 98.7°F might not need to worry until they hit a higher number.
Bottom Line
The idea that human body temperature is exactly 98.6°F is more myth than medical fact. While it served as a convenient benchmark for many years, modern science shows that our body temperatures vary more than we once thought—and that the average has likely dropped over time.
Instead of treating 98.6°F as the universal norm, it’s more accurate to think of body temperature as a range, generally between 97°F and 99°F. What’s “normal” for you might be a bit different from your neighbour, and that’s perfectly okay.
No comments:
Post a Comment