# Manpower

This is one of those posts that tells you something that you never cared to know, but you are going to know it after you finish reading.

The fact is, you are a little heat engine. You eat food, the food metabolizes, your body generates heat, the heat goes out into your surroundings, you generate more heat to replace that. The question is “how much?” How much energy in the form of heat to you put out for a given time.

Recall from Physics 101 that energy divided by time is power. I am going to work with watts as a unit of power.

You put out 100 watts. Imagine a 100-watt incandescent lamp. It consumes electric power at a level of 100 watts, and it puts out energy at a rate of 100 watts in the form of light and heat, mostly heat.

OK, the 100 watts is for an “average” person sitting, watching TV. Get up, walk around, talk, go for a jog, you’re going to burn more energy per second (more watts). Take a nap, and you’re going to burn less. Bigger people burn more energy. Smaller people less. In a cold room you’re going to pump out more heat, because your surroundings are going to suck more out of you, and your metabolism is going to go into overdrive to make up the slack. Anyhow, say 100 watts.

How is this power consumption (and output) apportioned to the parts of the body? With no physical activity the internal organs are the factory floor for power consumption. And the winner is: The brain. This piece of meat the size of a large grapefruit pumps out 25 watts, about one fourth of the total body output. OK, this source says 20 watts, but those people probably voted Republican.

So, this is remarkable if you think about it. And I am sure you will be thinking about it now. And chewing up the world’s limited supply of available energy.

## One thought on “Manpower”

1. As a percentage humans do consume a huge percent of their energies on their brains. The interesting thing is to know why humans took this bet a couple of million years ago. The bet was a risky survival strategy. But took off and won better than Facebook.com.

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