Human bodies are powerful heat-making machines

Today’s question:

If our normal body temperature is 98.6 F, why does it feel warm when the ambient air temperature is 98.6 F?

Easy-peezy.

Even I figured this one out without having to look it up.

We generate a lot of heat just keeping things running, enough heat to bring our core temperature up to 98.6 degrees just sitting around thinking, which is mostly what I do.

Why is it so hard to get out of bed on these cool mornings? Because just by being there under the covers you cooked up enough heat to make it all nice and cozy.

But that heat has to go somewhere. So we sweat and exhale warm air and without thinking about it, bring our blood vessels closer to the surface of our skin to cast off all that heat.

If we didn’t, we’d eventually just burn ourselves up.

So we need cooler air around us so there is somewhere for the heat to go. OK, so I lied.

I did look some stuff up and learned that in the 1950s the Marines did a study that created something called a wet bulb globe temperature index. And they found that under normal humidity anything over a wet bulb globe temperature index temperature of 77 brought on a risk of heat stroke.

And of course the flip side of this is a temperature that is too cold for human comfort, like when it gets below 70 in Phoenix. In too-cold temperatures, our body lose heat faster than we can keep it at 98.6.

So we need sweaters or blankets or furnaces or whatever to bring things back into balance.

And much depends on what your body is used to.

That’s why the snowbirds are golfing in shorts when it’s in the 60s while the rest of us are bundled up.

Have a question for Clay? Reach him at 602-444-8612 or clay.thompson@ arizonarepublic.com