My mind is always full of questions. Here are a few I have had regarding body temperature.
If my body temperature is 98.6, why does 98 degrees feel hot? Shouldn’t it feel like nothing?
AFAIK there is no “heat” organ in our bodies, nothing whose sole purpose is to be a heater. Whence cometh the heat?
Your body. Heat is a byproduct of work and you’ve got muscles contracting and expanding, organs churning away at their jobs, your brain is thinking, cells are dividing, immune system is fighting things, and so on and all of that is producing heat. Heat like so many other things moves from areas of high concentration to low concentration. When it’s 98F there’s not that much difference and you lose heat that much more slowly and feel uncomfortable. When it’s 40F, the difference is too great and not only do you lose excess heat but your body has to work harder to maintain your core temp which makes you uncomfortable. At about 70F, the differential is just about perfect and excess heat dissipates but you don’t have to work to maintain your core temp and so you feel comfortable.
No heat organ? Well, no, there’s no organ whose only purpose is to generate heat, but most of your organs generate heat in the process of functioning. Even more so when you are actively using them.
And that’s the problem. You need to dump that heat somewhere or else your body will get hotter and hotter until it shuts down.
That, incidentally, is why you don’t feel comfortable when it is 98 degrees outside. When the air temperature is lower, you can dump a good deal of your waste heat into your environment. When it is at or higher than body temperature, that becomes a much more difficult proposition and you can suffer from heat related illness (heat stroke, heat exhaustion, etc) because you can’t dump that heat anywhere anymore and it simply builds up in your body.
Mental Floss explains this better than I can, so give it a read.
Basically, our body is constantly producing heat and needs the environment to cool it down somewhat. At 35º (or 98 degrees for Americans) the difference between our body temperature and that of the environment is so small that we can’t cool down properly.
Thanks, very informative. Where are you people when I’m in the shower pondering life’s mysteries?
Open invitation? 
<nitpick> 35º is 95 for Americans. Body temperature is closer to 37 (98.6 for us).
FWIW, my “normal” body temp is 96.8. When I go to the Dr. and he takes my temp and says 99.5 is AOK, I tell him I have almost 3 degrees of fever; he couldn’t care less.
your body being a biochemical reactor produces heat.
there is brown fat which has the purpose of generating heat.
A friend of mine is a Dr. I asked him once where the heater in our body was and he started telling me about a gland that regulates our temp. I said I was not interested in the thermostat I wanted to know about the heater. He got very frustrated and said," why are you asking me this". He didn’t know how to explain it I assume. I have always assumed that oxygen was binding with nitrogen and hydrogen compounds stripping them of carbon somehow creating heat durring the reaction, but really have no idea for sure.
As this is more of a fact-based question rather than a solicitation of personal opinion, I’m shipping this thread off to General Questions.
Just outside, in the bushes by the rhododendron.
Not only is everything in your body a heater, but everything, period, is a heater. Well, everything that involves energy in any way, at least. If you eat 3000 Calories worth of food, by the end of the day, almost all of those Calories have been converted to heat. If your computer draws 100 watts, then every thousand seconds (16 minutes 40 seconds), it has produced 100 kJ of heat. If you burn ten gallons of gasoline in a road trip in your car, when you pull back into your driveway you’ve converted the entire energy content of 10 gallons of gasoline into heat.
I’m standing right behind you. I love you that much more than Telemark does.
<nitpick on nitpick>Really, US body temp is 98- to 99-ish. 98.6ºF is just 37ºC converted to Fahrenheit with an additional sigfig for no good reason other than years of elementary school teachers drilling it into students’ heads. Body temperature is not maintained in anywhere near as tight a range as “98.6ºF” implies.
My “normal” is 97.1 and my doctor is the same way. Apparently 100° is the common baseline for “fever”, an individual patient’s “normal” notwithstanding.
There’s an old joke about a guy who got rid of the speedometer in his car because he didn’t need it. When asked how he knew how fast he was going, he said At 30MPH the doors rattle, at 40MPH the hood also rattles, at 50MPH the steering wheel rattles, too, and at 60MPH, I rattle along with the rest.
At 98 degrees, my ears talk to me, at 99, my eyeballs get in on the act, and at 99.5 I can’t see anything because said eyeballs are running like a faucet. Above that, euphoria sets in as I start to talk to dead relatives. Any of this sound familiar?
There’s the time I was sick in bed and may have hallucinated my SO coming to check on me and see what I wanted for dinner.
On the other end of the spectrum, I had to go to the emergency room once–in the middle of a snow storm, and the car heater was on the fritz–and when the ER nurse tried to take my temp, she couldn’t find it. I said what’s the lowest that reads and she said 92 degrees. I asked her, jokingly, if I was dead and she was not amused. When it got to 94.7, they could take blood 
. I said when it gets to 100, sell! She was not amused.