Last revised 1/2000 by Marguerite Tonjes 3/12/97 - Why is 72 degrees Fahrenheit the most comfortable temperature?

## Why is 72 degrees Fahrenheit the most comfortable temperature?

(Lansing State Journal, March 12, 1997)

Our body temperature is 98.6 degrees, so why shouldn't that be the most comfortable temperature? Our bodies generate heat at a certain rate, and to remain at a constant 98.6 degrees we must dissipate excess heat to the air. It's just like your car engine needs coolant. Your engine would heat up until some part melted and the engine stopped running.

Furthermore, if two objects touch, the rate that heat flows from one to another depends on the temperature difference between the objects. If you stand outside in the winter, the cold air causes heat to flow quickly and your body temperature will drop. However, if the temperature outside was 98.6 degrees, no heat would flow and your body temperature would rise because of the heat you generate.

We need to be surrounded by air that is cooler than our body temperature by just the right amount so that heat flows away from our bodies at the same rate we generate it. That temperature is 72 degrees.