How much energy does your body give off on a normal basis? Which part of your body gives off the most heat? What is this amount

  • 2
    It is not clear what exactly you are asking here: What is a normal basis? What do you mean by give off, overall energy expended, heat loss, ...? Much more specific information is necessary to give a useful answer.
    – imsodin
    Feb 7, 2016 at 18:39
  • 5
    Rule of thumb: a person is a 100 watt heater.
    – ab2
    Feb 7, 2016 at 21:02

1 Answer 1


Basal metabolic rate is about 75 watts. That is, this is the price of keeping a normal body temperature. Can drop some during sleep.

Light exercise -- you can talk, but not sing without excessive pauses -- raises this to 200-300 watts. A trained athlete can generate 500-1000 watts for extended periods of time.

A person has about 2 square meters of skin. Under comfortable conditions, the skin is at a fairly constant temperature. As you bundle up for colder weather, more heat is lost on the exposed bits, and less on the covered bits.


A: When under cold stress, the body shuts down surface circulation to the extremities. (Cold fingers, toes) then arms and legs.

B: Blood circulation to the head is not restricted during cold stress.

The combination of these two factors and given environments is the source of such sayings as "You lose X% of your heat through your head"

However, "if you hands are cold, put on your hat" remains good advice.

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