Drinking Hot Tea To Cool Down
Last Updated: Dec. 8, 2014
The idea that drinking a hot beverage like tea can cool you off may seem counter-intuitive. During hot weather, many tea drinkers in the U.S. switch to iced tea. Hot drinks add significant heat to the body, so the only way a hot drink can cool a person off is by causing changes in the body that cause greater cooling than the amount of heat gained.
The human body naturally regulates its temperature through a variety of means, including changes in metabolism and blood circulation, perspiration, and heat loss through the skin and through breathing. The main two ways that hot drinks could produce a cooling effect is by slowing down the metabolism so that the body generates less heat, or by increasing heat loss, such as by increasing sweating.
Scientific study of hot drinks and thermal regulationA small and recent scientific study has validated that drinking hot fluids can indeed cool the body during conditions of exercise, but only under conditions allowing for full evaporation. This is due to the fact that drinking hot fluids increases the amount that a person sweats.
The increased cooling will not necessarily take place if there is little air circulation, if the air is very humid, or if a person is wearing a lot of clothing. The research on hot fluids and thermoregulation is very new, and there are many unanswered questions about how and when it happens. One of the suggestions offered, by Peter McNaughton of Cambridge, is that receptors in the mouth respond to heat. This would allow a relatively small amount of hot liquid to send a signal to the body that could activate its thermoregulation mechanisms pre-emptively, leading to a greater cooling effect than the warming effect of drinking the liquid.
One of the researchers studying hot fluids and thermoregulation, in an interview with the Smithsonian, recommended that, based on his research, hot tea would be a good way to cool down on a hot day, when wearing less clothing, but would not be as helpful in very humid conditions.
1. Bain AR, Lesperance NC, Jay O., Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation., Acta Physiol (Oxf), May 10, 2012. doi: 10.1111/j.1748-1716.2012.02452.x.
2. Cool Down With A Hot Drink? It's Not As Crazy As You Think, The Salt, NPR, July 11, 2012.