Why is our body temperature 98.6 degrees?

Always wondered why our body temperature is 98.6 degrees, did we not do the calculations for temperatures correctly from the beginning? Why isn’t it 90 or 100 or something even? It’s just such an odd number. What would it be in metric measurement? Maybe that’s what is wrong. Or is it the same all over the world?

Huh?

98.6 F works out to precisely 37 C. I’ve heard that 37 C was the value that had been measured in Europe, and that they simply converted directly using the (9/5) C + 32 formula. The 98.6 does seem a bit too precise, given that there are only two significant digits in that 37. And human body temperature does vary a bit.
edited to add:

See here, under History

Yeah, it’s not really 98.6 at all. There are significant variations from person to person, and studies usually put the true average slightly lower than that. I think it is just a byproduct of someone converting 37 C into Fahrenheit.

Cecil has written everything you’d ever want to know about it.

ETA: It’s pretty impressive when you Google “farenheit origin” and Cecil’s column ranks first :cool:

It was originally 96 and/or 98 in Fahrenheit

The original intention was that the zero point of the Fahrenheit scale be the freezing point of a concentrated brine, the lowest temperatore that could be reliably created at the time, and the 100 degree point be body temperature. After the scale was established, finer calculations showed that normal body temperature was something over a degree F below the 100 mark that had been established. Keeping the freezing-to-boiling point for water at exactly 180 degrees seemed more useful to the scientists calibrating it than making the exact value of body temperature an even number. Hence the 98.6 degrees temperature for the average body temperature of an average healthy human being (many people’s norm is above or below the 98.6 value by up to a degree or so).

Edit: Polycarp’s post defeated mine.

Interesting point about the strangely precise value of 98.6 being common knowledge, I never thought about it but people really might as well just say it’s 99.

When Fahrenheit originally defined his scale he defined body temperature as 96 degrees, giving him 64 degrees between freezing and body temperature (and making the subdivisions easier to mark on his thermometer).

The scale was later revised so that there would be exactly 180 degrees between water freezing and boiling, this moved the body temperature point to about 98 degrees. (largely cribbed from the wikipedia article on Fahrenheit)

This all explains why the Fahrenheit scale places the average body temperature where it does.

But I have a related, but different question: Why is the human body temperature what it is (allowing for normal variation)? Other animals (cats, for instance) have a normal body temperature that’s significantly higher, on the average, even allowing for some variation.

My normal body temp is only 97 degrees. Mom said it runs in the family.

You are all WRONG.
But that’s OK, because we are all human.
98.6 comes from a song that went something like “Hey 98.6, it’s good to have you back again…”
The song was good, and easy to remember, so that is where 98.6 comes from.
If you have any other questions, let me know, I’m about to break out some old 33 1/2 records to research things further.

In the morning until around 11 or so mine is under 97. Normally around 96.5. Love going to DR or giving blood in the morning. I always get the are you felling OK?

I’m confused about the picture linked in the original post. Does it bear any relevance to the content of the post, other than being a random picture of a foreign person?

It’s a picture of someone from the world! Maybe she owns some possessions.

I thought we were nominally 310ºK.

Probably because they have a faster metabolism in general.

But presumably there must be some evolutionary adaptation at play. I assume body temperature is optimized for the various chemical reactions that need to occur in the body and maybe for other things as well. So the question is, what is different in a Cat’s body or lifestyle that makes a different temperature advantageous?

This reminds me of my high school biology class, when the question was asked why humans couldn’t be the size of elephants. The answer was that if we were, we’d overheat and die. I wondered, but didn’t ask, ‘Well, if we were the size of elephants, wouldn’t we have evolved in such a way that temperature would not be an issue?’

I recommend reading through this paper: Scaling of body temperature in mammals and birds (.pdf doc). Per the abstract:

**Our standard body temperature strikes a perfect balance between maintenance of our metabolism and resistance to fungal infection.Humans and other advanced mammals are very hot compared with other animals. **.

From the sturdy of Arturo Casadevall, M.D., Ph.D., professor and chair of microbiology & immunology at the Albert Einstein College of Medicine of Yeshiva University.

Link