Many of us grew up being told that the best way to cool off in summer was to drink hot tea. It seemed to make perfect sense, have a cup of tea to increase your body temperature and sweat more. But what does the science say?
Researcher Ollie Jay, a specialist in human kinetics conducted studies on this subject in 2012 and 2014. He found that drinking hot tea on a hot day does make you sweat more and can cool the body so long as the sweat generated evaporates from the skin (rather than being soaked into clothing you may be wearing or dripping straight onto the ground). This means the cooling effect is most noticeable in dry heat rather than humid conditions where the sweat sits on the skin.
So the science is saying yes, but the reason why is not what I had always understood it to be. Researcher Jay's testing showed that the cup of tea did not increase the body temperature, his second study in 2014 showed that the sweat response is likely linked to temperature sensors in the stomach controlling the sweat sensors.
A recent article on Stuff quoted another expert Peter Poortvliet as saying: "You have only four ways of losing heat from your body:- conduction, where your skin comes into contact with cold metal or water; convection, where wind blows over your skin; radiation, when it is cooler outside and the body give off heat; and evaporation, when sweat on your skin evaporates and uses heat".
The fourth way listed is where your hot cup of tea comes in handy.
So if you are in those parts of NZ experiencing a dry heat then enjoying a cup of hot tea might definitely help your comfort levels. Pop the kettle on.
Academic: Full research report: https://www.ncbi.nlm.nih.gov/pubmed/22574769
or report extract: https://www.ncbi.nlm.nih.gov/pubmed/22574769
Magazine or article sources::
Popular Science article by Marissa Shieh: https://www.popsci.com/does-drinking-hot-liquids-cool-you-off
Posted: Tuesday 13 February 2018