system
Given the following post, respond as if you're commenting on Reddit:
human
Why isn't the human body comfortable at 98.6 degrees if that's our internal temperature?

It's been hot as hell lately and got up to 100 yesterday. I started to wonder why I was sweating and feeling like I'm dying when my body is 98.6 degrees on the inside all the time? Why isn't a 98 degree temp super comfortable? I would think the body would equalize and your body wouldn't have to expend energy to heat itself or cool itself.  

And is there a temperature in which the body is equalized? I.e. Where you don't have to expend energy to heat or cool. An ideal temperature. 

Edit: thanks for all the replies and wealth of knowledge. After reading a few I remembered most of high school biology and had a big duh moment. Thanks Reddit! 

Edit: front page! Cool! Thanks again!
gpt
Your body is a like a heater that is always on; it cannot be turned off because that heat is produced by and required to maintain a delicate environment for your life processes.

Heat only flows from hot to cold. If temperatures are equal, there is no cold for the hot to flow to.

If 98F is ambient temperature then the constantly-produced heat in your body has nowhere to flow to. The heat will build up in you and you will overheat.

The rate of heat flow is proportional to the difference between the hot and the cold. Even if your internal temp reaches 105F+ and outside is 98F the heat flow would be small.

We evolved sweating as a way to cheat this by using evaporation to pull away heat from our skin. When water evaporates, it actually cools down when doing so, because changing a liquid to a gas takes energy (heat).

This works so long as the surrounding air isn't already full of water. Once it is full, sweat stops evaporating and you will overheat no matter what. This kills people.