Be Cool

A question on Ask Yahoo today mirrored one recently asked me by a nephew:

Dear Yahoo!:
If our normal body temperature is 98.6 degrees, why do we feel uncomfortable when the air temperature is 98 degrees?

And the answer (again courtesy of Ask Yahoo):

Think of your body as a steam engine. Under normal temperatures, it generates more heat than it needs. It’s generally agreed that room temperature (68 to 72 degrees Fahrenheit) allows the body to dissipate “waste heat” with the least amount of effort.

How so, you ask? Because heat naturally transfers from warmer to cooler environments. Room temperature lets nature do its thing with minimal effort on our part, but when the ambient temperature rises, it takes more energy to get rid of excess body heat.

When the outside temperature approaches our body temperature, there’s no natural convection cooling mechanism at work. The body has to work incredibly hard to dissipate heat, which it does through the lovely and aromatic act of sweating.

All of this helps to explain, of course, why the typical human’s skin temperature, all else being equal, is around 91 F, or almost nine degrees less than the “normal” core temperature of 98.6.

I won’t belabor the point, but heat transfer mechanisms in the human body — perspiration, convection, radiation, and conduction — are a  fascination of mine, and it was the underlying metaphor in a talk I gave years ago on startups and their ability to grow rapidly and thrive.


  1. Belabor the point. What was the connection?

  2. Once upon a time I did T’ai Chi in Vancouver’s Q.E Park on the weekends. My sifu would teach us kids all year round (snow, rain).
    Paul, how is that I could see a steady flow of dense steam coming off the body of sifu as he wore a t-shirt in less than zero doing only the most minimal Wu style movements? That while I froze my butt in heavy clothes doing (big movement) Yang style? That is, beyond me blowing hard on The Great Cosmic Monkey God….
    Wu style or Yang style, Master K?