As temperatures soar during the current heat wave, many people are seeking ways to stay cool. While cold drinks and ice lollies are popular choices, researchers suggest that a hot cup of tea or coffee might be more effective—but only under certain conditions.
How Hot Drinks Cool You Down
A 2012 study from the University of Ottawa examined the effect of hot beverages on body temperature. The findings, published in the Smithsonian Magazine, indicate that hot drinks can actually lower the amount of heat stored in the body, provided the sweat they induce can evaporate.
Dr. Ollie Jay, one of the study's authors, explained: "If you drink a hot drink, it does result in a lower amount of heat stored inside your body, provided the additional sweat that's produced when you drink the hot drink can evaporate."
When you consume a hot beverage, your body sweats more. As sweat evaporates from the skin, it removes excess heat by converting liquid water into vapor, effectively cooling you down more than the heat added by the drink.
The Role of Humidity
However, this cooling effect depends on the environment. In humid conditions, sweat does not evaporate as efficiently, making hot drinks less effective. Dr. Jay noted: "On a very hot and humid day, if you're wearing a lot of clothing, or if you're having so much sweat that it starts to drip on the ground and doesn't evaporate from the skin's surface, then drinking a hot drink is a bad thing. The hot drink still does add a little heat to the body, so if the sweat's not going to assist in evaporation, go for a cold drink."
Therefore, in hot, dry climates, hot drinks can be a cooling aid, but in humid areas, cold beverages remain the better choice.
