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Time to redefine normal body temperature? (2020)

health.harvard.edu

31–40 of 148 posts

Re: Time to redefine normal body temperature? (2020)

#31
Normal body temperature seems to be falling over time. An analysis of 20 studies between 1935 and 1999 found that the average oral temperature was 97.5˚ F. And a 2017 study of more than 35,000 people found an average body temperature of 97.9˚ F.

I wonder if this can explain rising worldwide rates of obesity.

Re: Time to redefine normal body temperature? (2020)

#34

I have always felt that 37C was way too precise an answer for a human's body temperature. How is it that a measurement based on the freezing and boiling point for water coincidentally lands on a nice even number for a human's body temperature. It's one of my issues with biological sciences that they sometimes try to come up with precise answers as they do in physics or chemistry, when most of the time answers, such a…

Even “around” is meaningless without context. A hot day is around 37c (+/- 10), a healthy person is around 37c (+/- 1) and a manufacturing process could call for a temp around 37c (+/- 0.1).

> A hot day is around 37c (+/- 10)

Absolutely not. 47C is an emergency, not "hot".

Re: Time to redefine normal body temperature? (2020)

#35
post #11
post #4

Not sure if it's all the countries, but I have always heard the normal body temperature in Celsius stated as 36.5, which is 97.7 F. Is 98.6 an american-only thing?

Yes, it's a conversion of 37C which is stupid since 37C is when I have a fever already

37 may or may not be a fever depending on your activity. If you went running your body temperature will be above 37 but you'll feel perfectly normal. When you got 37 and it's a fever it feels different.

Re: Time to redefine normal body temperature? (2020)

#36
post #3

As the article says, Wunderlich reached a conclusion of 37C in the 1800s, and that’s what we’ve used since then. The real problem appears to be that converting to Fahrenheit and reporting this as “98.6F” suggests an order of magnitude more precision than “37C”. 36.5C would still round to 37 but corresponds to 97.7F.

I thought the same, so I tried to find Wunderlich. The only source I could find ( https://www.google.com/books/edition/_/3-wHAAAAIAAJ?hl=en&gb... ) seems to have Wunderlich reporting "98.6F", and then converting to Celsius: > The average normal temperature of the healthy human body in its interior, or in carefully covered situations on its surface, varies, according to the plan of measurement from 98.6° to 99.5° Fahr…

Interesting that the original german text uses Celsius as the primary measurement, and provides conversions in Rankine. No mention of Fahrenheit.

Funny that people argue over this and some guy named Wunderlich who measured a bunch of asses.

Did he write that translation or is Google Books fake news?

Re: Time to redefine normal body temperature? (2020)

#38
> [One key possibility] ... Lower metabolic rate: One of the biggest determinants of body temperature is your metabolic rate. Like a car engine that’s idling, your body expends energy just keeping things going, and that generates heat. A lower metabolic rate in modern times could be due to higher body mass (some studies link this with lower metabolic rate), or better medical treatments, preventive measures, and overall health.

I know it's not exactly "thinking with statistics", but it strikes me as too coincidental that the obesity epidemic has only exploded in recent decades too.

Re: Time to redefine normal body temperature? (2020)

#39
post #33

Several people in the medical field have told me they do not consider 99.x as a fever. Edit: Found a link: https://www.osfhealthcare.org/blog/whats-considered-a-fever-... 100.4 is their threshold.

As a dad, I don't consider my kids to have a fever until they are closing in on 101. They each run hot to begin with, but also the thermometers generally available to the public never seem to be particularly accurate.

Re: Time to redefine normal body temperature? (2020)

#40
Is it possible that thermometer calibration has just drifted slightly over the last couple hundred years? If you told me that the typical electronic thermometer today actually measured around a degree different than the mercury thermometer Wunderlich presumably used, I wouldn't be all too surprised.

Or is there really an accurate and consistent calibration technique that's been in use since at least the 1800s, so we know for sure that it must be humans themselves getting cooler?

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