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Help coming up with a formula for determining weight lost in cold.

  1. Nov 23, 2005 #1
    When you're cold, your body naturally burns calories to keep you warm. So it makes sense to me that if people were to just stay out in the cold enough, that they could lose some weight. Also, it seems that you could probabally figure out a formula to determine exactly how much weight you'll lose depending on how much you weigh, how long you stay out in the cold, and how cold it is. Though I suppose the specific heats of your bodily substances besides water would be of great importance in figuring it out exactly...

    So first off, I'd have to know the average specific heat of the organic compounds in your body, then find the average specific heat of your body as a whole. After I've got the average specific heat of the human body, I'd need to know exactly how much heat cold air would "steal" form the body per a specific temperature.

    Could anyone help me out a bit here? I'm somewhat brain-boggled right now, and can't really think of how this would work out...
  2. jcsd
  3. Nov 24, 2005 #2
    yea, i guess it does make sense but i think it's the same as starving youself. in the cold, you burn more calories to function your body AND to keep warm so you would quickly feel hungry, so you eat to get more calories and the same goes on. keep on burning and eating. if you don't eat, you'd lose weight (in an unhealthy manner) by starving yourself in the cold.
  4. Nov 25, 2005 #3


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    Yes, I've maintained that the best way to lose weight is to open the refrigerator....and stay put. :biggrin:
    The specific heat is not what you want. THere are two quantities more important that it, which determine the rate of heat loss. They are : (i) the mean thermal conductivity of body tissue, and (ii) the convective heat transfer coefficient of skin (with/without hair). Get these numbers, and I'll help you with the calculation - this is a physics probem, even if it is set in a biological context.
    Last edited: Nov 25, 2005
  5. Nov 25, 2005 #4
    It might be good to acknowledge that the body can only break down fat at a set rate. If this was not so then people would not freeze to death until they starved. Hope this has some meaning.
  6. Nov 28, 2005 #5


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    You would also have to factor in the individual's metabolic rate, how much fat reserves they have (not just as an energy supply, but also as insulation), whether they are eating any other food that provides energy, etc. What you really need to figure out isn't just how quickly a body loses heat, which would only apply to a corpse (such a measure can be used to help approximate time of death), but at what ambient temperature the body cannot provide enough heat energy through metabolism, shivering, vasoconstriction in extremities to keep blood restricted to the body core, etc., to maintain body temperature. In other words, when does the rate of heat loss exceed the ability of the body to generate heat. The temperature at which this occurs would also depend on things like humidity, which would affect conductivity of the heat away from the body. For example, you can maintain body temperature fairly well in 68 degree (F) air, but jump into a 68 F body of water, and hypothermia becomes a concern.
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