# How do we regulate body temperature? **URL:** \ **Category:** Factual Questions\ **Created:** [October 5, 2000, 1:19am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705 "2000-10-05T01:19:39Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Skwerl](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Skwerl](https://boards.straightdope.com/u/Skwerl)\ **Post date:** [October 5, 2000, 1:19am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/1 "2000-10-05T01:19:39Z")
Say it gets colder out…your body has to keep you warm to survive…but how? Does the heart pump harder and the friction causes heat? What makes humans (and mammals) warm? Is it some chemical reaction that releases heat? What chemicals? ---
**Author:** ![Dr.Lao](https://avatars.discourse-cdn.com/v4/letter/d/2bfe46/32.png) [@Dr.Lao](https://boards.straightdope.com/u/Dr.Lao)\ **Post date:** [October 5, 2000, 1:41am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/2 "2000-10-05T01:41:45Z")
The first step the body takes to conserve heat is to lower blood flow to the extremities. Blood is very nearly at core body temperature (the temperature of the center of the chest cavity) and if it can be prevented from cooling too much during its trip through the body, the body will stay that much warmer. If your body is still losing heat, you will evenually start shivering. The heat gain from normal medabolic function is increased when the metabolism is forced to work harder. Shirvering accomplishes this through increased muscle movement. If shivering fails to keep you warm, your body has run out of options. It will switch to survival mode where energy is concerved to the utmost and nonessential body functions are shut down. This is when hypothermia sets in. You can only hope you get warm soon or the cold will kill you. This is what I understand happens, but I welcome a better explanation if someone has one. ---
**Author:** ![Skwerl](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Skwerl](https://boards.straightdope.com/u/Skwerl)\ **Post date:** [October 5, 2000, 1:52am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/3 "2000-10-05T01:52:03Z")
But what makes the blood in the chest cavity warm, I mean? Is it just the friction of the blood against the veins that causes it to heat up? Why aren’t we pumping room-temperature blood around? ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [October 5, 2000, 2:33am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/4 "2000-10-05T02:33:57Z")
Heat is released as a natural byproduct of all the chemical reactions taking place throughout the body. Thank the wonderful laws of thermodynamics. Every single reaction releases some heat. Usually, we’re more concerned with getting rid of excess heat - sweat, etc. ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [October 5, 2000, 2:37am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/5 "2000-10-05T02:37:35Z")
Your metabolism–the “burning” of food\* to produce energy (is what keeps your blood warm). \*–I could get technical about that, but I’m sick, stoned on Tylenol Cold Nighttime (note to self: don’t drink tonite), and generally feeling crappy. Ask me again next week. ---
**Author:** ![bizerta](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@bizerta](https://boards.straightdope.com/u/bizerta)\ **Post date:** [October 5, 2000, 2:41am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/6 "2000-10-05T02:41:06Z")
A chemical reaction turns food + oxygen into heat. Calories are not a measure of fat or weight. Calories are a measure of heat. You really do “burn” calories. One food calorie (actually a kilocalorie) when burned with the oxygen we breathe will raise one kilogram of water one degree Celcius. So a 50 kg woman (110 lbs) consuming 1800 calories a day eats enough energy to raise her entire body temperature 1800/50 or 36 degrees Celcius. Or about 1.5 degrees C per hour. ---
**Author:** ![Skwerl](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Skwerl](https://boards.straightdope.com/u/Skwerl)\ **Post date:** [October 5, 2000, 3:05am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/7 "2000-10-05T03:05:10Z")
So,not to hijack my own thread,would eating a few Snickers bars, or better yet a handful of cane sugar, be a way to stave off hypothermia, because all the calories would warm you up? Or is the heat created negligible? ---
**Author:** ![Arjuna34](https://avatars.discourse-cdn.com/v4/letter/a/eb8c5e/32.png) [@Arjuna34](https://boards.straightdope.com/u/Arjuna34)\ **Post date:** [October 5, 2000, 3:26am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/8 "2000-10-05T03:26:46Z")
> [@](#): > > \*Originally posted by Skwerl \* > \*\*So,not to hijack my own thread,would eating a few Snickers bars, or better yet a handful of cane sugar, be a way to stave off hypothermia, because all the calories would warm you up? Or is the heat created negligible? \*\* You’d already be burning the fuel you ate before you got cold. If you had been starving yourself for a while, your body would start consuming fat stores, etc. Arjuna34 ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [October 5, 2000, 3:49am UTC](https://boards.straightdope.com/t/how-do-we-regulate-body-temperature/35705/9 "2000-10-05T03:49:36Z")
Yeah, heat is created through the burning of the stores already absorbed into your body. After eating, the food still has to be absorbed and processed before giving off any significant amounts of heat. By the time it gets that far, you’ll probably be back inside or dead from hypothermia. Eating when cold will more likely divert needed warm blood to the stomach to aid digestion, making you colder elsewhere. Of course, if you’re on, say, an extended outdoor recreation, then by all means, eat. You’ll need the energy later.