BBC Two - Can hot drinks cool you down? - BBC

Can hot drinks cool you down?
In the UK, we are used to drinking hot drinks to warm us up and cold drinks to cool us down. But there are many places around the world where people drink hot drinks to stay cool in their tropical climate. This may seem counter-intuitive, but is there a scientific basis to this habit?
The Experiment
We sent Dr Giles Yeo to Nottingham Trent University, where sports scientist Dr Steve Faulkner put the theory to the test. On two consecutive days, Giles was instructed to walk briskly on a treadmill for an hour, in a room set at 35°C in low humidity. On the first day, he drank a measured amount of water chilled to 4°C at 15 minute intervals, and on the second day, he was given cups of tea at 43°C. Throughout the experiment, his skin temperature was measured by sensors placed around his body, and his core temperature was measured with a telemetry pill which he swallowed a few hours before each test. The amount of sweat that Giles produced in each condition was measured by weighing him before and after the treadmill session.
The Results
Steve’s results compared Giles’ core body temperature over the two days. He found that it was almost identical – the hot drink did not cool Giles down any more than when he had a cold drink.
Wider Research
Evidence from a larger study in Australia indicates why that might be. It involved nine people who exercised for 75 minutes, and were given drinks at different temperatures, ranging from 1.5 to 50 degrees Celsius. The scientists concluded that no matter how hot or cold your drink, your body will respond to keep your core temperature steady at around 37 degrees Celsius. A hot drink means your body will sweat faster, to get rid of the excess heat; however after a cold drink, your body will sweat more slowly.
What should I do?
When you’re hot, the key thing is to stay hydrated – and your drink can be as hot or cold as you like!