Britain is bracing for a spell of intense heat, raising a familiar question for many: should what you drink change when temperatures soar? The Met Office has issued a red extreme heat warning for Wednesday and Thursday.
Forecasters have said June’s all-time daily temperature record is expected to be broken. The latest red warning follows earlier amber extreme heat alerts.
The warnings are in place from Monday through to the end of Thursday, affecting much of southern and central England, along with large parts of Wales.
As the heat builds, people are likely to do whatever they can to stay cool and safe, from closing curtains and finding shade to drinking plenty of water or reaching for an ice lolly. For many, putting the kettle on for a piping hot cup of tea will be the last thing that comes to mind.
However, it may come as a surprise that hot drinks, including tea and coffee, could in some circumstances help the body cool down.
A 2012 study by researchers at the University of Ottawa looked at how drinking hot beverages affects body temperature. The research found that a hot drink can help cool you down, but only when conditions are dry enough for sweat to evaporate effectively.
Dr Ollie Jay, one of the study’s authors, told Smithsonian Magazine: “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.”
Put simply, a hot drink can make you sweat more. If that sweat evaporates properly, it helps remove heat from the body, potentially cooling you down enough to outweigh the warmth added by the drink itself.
While sweating can feel uncomfortable, it’s a vital bodily function that helps regulate our temperature. As perspiration evaporates from your skin’s surface, it eliminates excess heat by transforming the water from liquid to vapour.
Nevertheless, in humid conditions, this cooling mechanism becomes less effective, meaning hot drinks won’t assist in cooling you down. Dr Jay explained: “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.”
The key takeaway is that in hot, arid conditions, consuming a hot beverage can actually cool you down, whereas in humid environments, you’re far better off reaching for something cold.
