# I may be a diabetic, but I'm not adiabatic: what is exothermic at any one moment in my metabolism? **URL:** \ **Category:** Factual Questions\ **Created:** [October 11, 2016, 6:06pm UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262 "2016-10-11T18:06:57Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [October 11, 2016, 6:06pm UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/1 "2016-10-11T18:06:57Z")
See query. You know, what with being warm-blooded and all. Can it be said how more or less clearly for my lame brain?; i.e., I “know” that fat and glucose and the hypothalamus all come into play, but then I get lost in the trees. Somewhere there has to be – _one? many different?_ – exothermic chemical reactions that you can point to and say: the temperature has just gone up 0.00x°, thus (re-)warming up _this_ spot, and then the bloodstream (only?) picks up the heat from all these spots is passes through – _is this so broad as to be wrong?_ – and makes sure entropy doesn’t win for a while. [If it sounds like this OP started out as wordplay, it’s because it did. I then realized it was true Ithe-less-symbolic-version-ofRL but didn’t know why.] ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 12, 2016, 1:54am UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/2 "2016-10-12T01:54:58Z")
Here’s some reading to get you started until a real bio guru stops by. The article is short on details about the thermodynamics, but it’ll give you a host of new terms to chase down. > **[Cellular respiration](https://en.wikipedia.org/wiki/Cellular_respiration)** > > Cellular respiration is the process by which biological fuels are oxidised in the presence of an inorganic electron acceptor, such as oxygen, to drive the bulk production of adenosine triphosphate (ATP), which contains energy. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into ATP, and then release waste products. > The reactions involved in respiration are catabolic reactions... ---
**Author:** ![armedmonkey](https://avatars.discourse-cdn.com/v4/letter/a/d6d6ee/32.png) [@armedmonkey](https://boards.straightdope.com/u/armedmonkey)\ **Post date:** [October 12, 2016, 2:18am UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/3 "2016-10-12T02:18:02Z")
> [@Leo\_Bloom](#): > > Somewhere there has to be – _one? many different?_ – exothermic chemical reactions that you can point to and say: the temperature has just gone up 0.00x°, thus (re-)warming up _this_ spot, and then the bloodstream (only?) picks up the heat from all these spots is passes through –_is this so broad as to be wrong?_ – and makes sure entropy doesn’t win for a while. Entropy always wins. Always. Just about every bio-chemical reaction is exothermic. The few biochemical reaction that are endothermic are things like photosynthesis. You’re not a plant. Well, I’m assuming you’re not a plant, this is the internet, you could be an especially intelligent geranium named “Leo” wondering why “Leo Bloom” for all I know. Anyway, animals are an exothermic system. _Digestion_ itself is exothermic. There’s always heat loss. There’s always entropy. Shoot, there’s even heat loss in turning excess calories into fat. There’s heat lost in building muscle. There’s heat loss in a baby growing. Increased order in a small system does not mean entropy was cheated. Building that order is never 100% efficient. The perfection in efficiency is lost as heat. That’s why entropy always wins. However, how the body manages this heat may be the question you’re trying to ask. That gets into thermoregulation. That’s not about endothermic reactions, but rather dumping the thermal energy created by exothermic reactions when the temperature is too hot and speeding up some exothermic reactions when it’s too cold. ---
**Author:** ![armedmonkey](https://avatars.discourse-cdn.com/v4/letter/a/d6d6ee/32.png) [@armedmonkey](https://boards.straightdope.com/u/armedmonkey)\ **Post date:** [October 12, 2016, 2:38am UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/4 "2016-10-12T02:38:35Z")
Let me add to that. Diabetes does fuck up some of the thermoregulation. In a nut shell, insulin is the probably the most important hormone in metabolism, and metabolism is probably the chief component of thermoregulation. If either the production of insulin (Type I diabetes) or its receptors (Type II) is wonky, then the thermoregulation is wonky, too. Those reactions are all exothermic, though. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [October 12, 2016, 5:44am UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/5 "2016-10-12T05:44:07Z")
[This page](https://books.google.com/books?id=dWVJPYhnJHwC&pg=PA200&lpg=PA200&dq=heat+production+calories+muscles+human&source=bl&ots=61XqdcCnme&sig=ePJkljbBhWvSBydVjYxHkU-yqoQ&hl=en&sa=X&ved=0ahUKEwjkvZG6ttTPAhVERCYKHcLwBToQ6AEIWDAJ#v=onepage&q=heat%20production%20calories%20muscles%20human&f=false) might be of interest. Liver most constant source and active and muscles most involved in regulating heat production. Sources include the oxidation of food itself, especially protein, muscles (during strenuous exercise 75% of the energy goes towards heat production and only 25% to work), and then other organs. [This](http://www.tiem.utk.edu/~gross/bioed/webmodules/ATPEfficiency.htm) may also be of interest: > [@](#): > > Interpretation: An ATP efficiency of 38.3% is calculated under standard conditions (temperature is 298 Kelvin, pressure is 1 atm, pH is 7.0, and initial concentrations of reactants and products are equal). An EATP of -7.3 kcal/mol requires ATP, ADP, and phosphate to be present at equal concentrations. > > In cells, however the concentration of ATP is often 5 to 10 times that of ADP. As a result, the free energy of ATP hydrolysis is about -12 kcal/mol. In cells, the efficiency of energy extraction from glucose is approximately 50%. As a comparison, the efficiency of an electric motor or gasoline engine is about 10% to 20%. > > Conclusions: By examining the chemical reaction of glycolysis, we can determine the efficiency of ATP production in cells. Properties of cells, particularly the high ratio of ATP to ADP, contribute to the efficiency of ATP production under cellular conditions. Respiration is a successful process because the capture of energy into ATP bonds is relatively efficient. So 50% efficiency is pretty good for glycolosis and that means the other half if going to heat. Finally [this article](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2980962/) contains some tables that might allow an answer: Average masses, energy use per kg, and thus total energy used at rest by organs in the human body: Liver 1.39 kg; 200 Cal/kg/d = 278 Cal/d Brain 1.33 kg; 240 Cal/kg/d = 319 Cal/d Heart 0.31 kg; 440 Cal/kg/d = 136 Cal/d Kidneys 0.29 kg; 440 Cal/kg/d = 128 Cal/d Skeletal muscle @26kg; 13 Cal/kg/d = 338 Cal/d And on average 19 kg adipose and 24.7 kg “residual” with lesser contributions but still adds up to BMR. Muscles at work have less efficiency but at rest all are likely roughly 50% to heat, again with control being partly by how much muscle activity, and various cooling mechanisms (such as sweating and vasodilation) ---
**Author:** ![armedmonkey](https://avatars.discourse-cdn.com/v4/letter/a/d6d6ee/32.png) [@armedmonkey](https://boards.straightdope.com/u/armedmonkey)\ **Post date:** [October 12, 2016, 8:40am UTC](https://boards.straightdope.com/t/i-may-be-a-diabetic-but-im-not-adiabatic-what-is-exothermic-at-any-one-moment-in-my-metabolism/768262/6 "2016-10-12T08:40:07Z")
> [@armedmonkey](#): > > The perfection in efficiency is lost as heat. :smack: The _difference from_ perfection in efficiency is lost as heat.