# Body Temperature **URL:** \ **Category:** Factual Questions\ **Created:** [May 17, 2003, 2:58pm UTC](https://boards.straightdope.com/t/body-temperature/175897 "2003-05-17T14:58:59Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![gypsymoth3](https://avatars.discourse-cdn.com/v4/letter/g/85e7bf/32.png) [@gypsymoth3](https://boards.straightdope.com/u/gypsymoth3)\ **Post date:** [May 17, 2003, 2:58pm UTC](https://boards.straightdope.com/t/body-temperature/175897/1 "2003-05-17T14:58:59Z")
what makes humans 98.6 degrees as opposed to room temperature? is it caused by the friction of the blood going thru the circulatory system? is this where black or clear flame that’s supposedly around body temperature comes in? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 17, 2003, 3:32pm UTC](https://boards.straightdope.com/t/body-temperature/175897/2 "2003-05-17T15:32:31Z")
> [@](#): > > **Thermogenesis** (THER-moe-JEN-e-sis) > Heat creation. During uncoupled thermogenesis, free fatty acids are oxidized (burned) without producing ATP – the energy from the oxidation process is dissipated (as heat) into the surrounding tissues. Thus, it is considered a wasteful or metabolically inefficient process. During coupled thermogenesis, the oxidation process leads to the creation of ATP. [descriptive links here](http://www.drumlib.com/dn/th.htm) Friction, and the imaginary black and clear flames have nothing to do with body temperature. ---
**Author:** ![Phage](https://avatars.discourse-cdn.com/v4/letter/p/a4c791/32.png) [@Phage](https://boards.straightdope.com/u/Phage)\ **Post date:** [May 17, 2003, 4:20pm UTC](https://boards.straightdope.com/t/body-temperature/175897/3 "2003-05-17T16:20:38Z")
BTW, Thermogenesis above is described as a wasteful process. I thought that maintaining body temperature had a particular purpose, such as allowing other critical chemical reactions in the body. If not, could a body using purely coupled thermogenesis function as well or better than a regular human? (I see a book idea here; “The Modern Vampire”, cold as death, 5 times stronger (more ATP)) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 17, 2003, 6:18pm UTC](https://boards.straightdope.com/t/body-temperature/175897/4 "2003-05-17T18:18:57Z")
See the following Staff Report, by me and Doug Yanega, for more information on warm-bloodedness in general: [What makes some animals cold-blooded and others warm-blooded?](http://www.straightdope.com/mailbag/mwarmblood.html) SD Staff George ---
**Author:** ![Phage](https://avatars.discourse-cdn.com/v4/letter/p/a4c791/32.png) [@Phage](https://boards.straightdope.com/u/Phage)\ **Post date:** [May 17, 2003, 6:25pm UTC](https://boards.straightdope.com/t/body-temperature/175897/5 "2003-05-17T18:25:44Z")
Still, that does not explain _why_ body temperature needs to be what it is. What particular reaction is based on/improved by a temperature of 98.6 degrees? ---
**Author:** ![Goodbeem](https://avatars.discourse-cdn.com/v4/letter/g/958977/32.png) [@Goodbeem](https://boards.straightdope.com/u/Goodbeem)\ **Post date:** [May 17, 2003, 7:27pm UTC](https://boards.straightdope.com/t/body-temperature/175897/6 "2003-05-17T19:27:53Z")
I always thought that our body temperature was a trade off between the speed of chemical reactions and the temperature at which proteins start to desintegrate. When our body temperature would be higher certain chemical reactions would be even faster, but most of the proteins in our body would also be destroyed. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 17, 2003, 7:41pm UTC](https://boards.straightdope.com/t/body-temperature/175897/7 "2003-05-17T19:41:07Z")
> [@](#): > > \*Originally posted by Phage \* > \*\*Still, that does not explain _why_ body temperature needs to be what it is. What particular reaction is based on/improved by a temperature of 98.6 degrees? \*\* **Goodbeem** has it right. [This thread](http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=155338&highlight=poikilotherm) concerning the column I linked to above discusses this in more detail. It’s not a matter of a single reaction being improved, but of having the whole suite of metabolic reactions coordinated. I quote here some of my remarks in that thread: > [@](#): > > . . . the advantage of being a homeotherm is that it allows a much tighter integration and greater efficiency of the enzymes and other components of metabolic pathways. Any enzyme that controls a specific part of a metabolic pathway (a series of chemical reactions involved in metabolism) has a specific temperature at which it works best. Slightly different forms of an enzyme may work optimally at different temperatures. Having a stable body temperature allows an organism to develop a suite of enzyme forms that work together optimally at that temperature. If body temperature varies, enzymes can get out of sync, disrupting the metabolic pathway and making it less efficient. > > Chemical reactions generally run fastest at higher temperatures. The homeothermic strategy is based on having a high-activity life-style, so that homeotherms tend to regulate their temperatures to be close to the maximum feasible. Proteins, such as enzymes, start to denature at 45 C (113 F), so this represents a lethal temperature for most organisms, with the exception of some bacteria. Of course, it’s best not to have your usual body temperature too close to the lethal, or else you might keel over dead with any excess exertion. Mammals tend to regulate their body tempertures in the 90s (F), birds as high as 110. Some ectothemic desert lizards may be active close to the theoretical maximum of 113. > > . . . various animals may have adaptations that permit them to survive changes in body temperature that would kill a human. Remember, we are basically tropical, non-desert mammals, and the temperature extremes we can tolerate reflect that. Evolutionarily, there has been no reason to develop greater tolerance, so when our core temperture drops too low or gets too high, our metabolism is disrupted enough to kill us. Camels, on the other hand, can tolerate a degree of hyperthermia that would kill a human. On the other hand, some ground squirrels can allow their body temperature to drop to near freezing during hibernation, far below the level that would be fatal to a human. It’s all a matter of adaptation, within limits.