Will Hot Drinks Cool Us Down?
Posting Date: 06/04/2002
Original Posting: 6/5/2000
Kim: One hot night, my roommate and I had a disagreement. She said that drinking hot cocoa or eating hot soup would raise our body temperature and cool us off. My aunt, too, drinks hot coffee when she is hot and says it cools her off.
I think they are nuts. Iced tea and ice cream are what cool me off.
Dr. Dean: You are all demonstrating the power of perception. Body temperature is controlled by respiration and by the amount a person sweats, so neither hot nor cold food or drink will change body temperature.
If your roommate's idea is that raising the body's temperature would force it to work harder, sweat more, and therefore cool off, she is wrong. Food and drink don't change body temperature, and sweating too much can lead to dehydration, which is harmful.
As your roommate and your aunt demonstrate, perception varies, but most of us would say that drinking something cold cools us down, just like we feel warmed by a bowl of oatmeal on a winter morning. In fact, neither makes much difference.
Someone once sent me a calculation on the number of calories the body uses to cool or raise the temperature of a liquid. He asked why the body's temperature isn't affected by the calories being burned.
Given the mass of the body and its temperature, the bit of calories it takes to maintain a steady 98.6 degress is like throwing an ice cube into a tub of hot water. It's not going to drop the temperature enough to matter.
A lot of this mythology comes from the notion people have that drinking hot toddies on a cold day warms them up. Alcohol dilates the blood vessels so you feel warmer but actually you are losing body heat; the feeling that it's warming you up is an illusion.