We’ve nearly reached the peak of the summer, and it is hot in most places around the country, even here in the Pacific Northwest. With there being no sign of the temperatures diminishing anytime soon, most people would be inclined to reach for a chilled glass of iced tea or even a frozen tea infusion. Besides, some of the coolest iced tea makers, gadgets and flavors of tea come out around this time of year, so why not try them out? Likewise, it provides us tea lovers with an excuse to change up our hot tea routine and try something new or different.
However, you’ve also likely heard that it is actually better to drink hot tea rather than iced tea on a sweltering day. While this theory has been floating around for quite some time, I decided to do a little research and testing myself to determine if this is a valuable piece of advice or just an old wives’ tale.
The Rumor is True?
Apparently I am not the only one who has wondered about the validity of this rumor. When I began researching the topic to determine if there was any scientific evidence in favor it, I was surprised to find a couple of different scientists had studied the effects of drinking a hot beverages on a hot day. However, what was even more startling was that this speculation seems to be true.
Peter McNaughton, a neuroscientist at the University of Cambridge, told National Public Radio that while drinking something hot to cool off on a hot day sounds counterintuitive, it does actually work. The science behind why it works is that drinking hot tea activates the TRPV1 receptor in your tongue that responds to heat. This receptor then sends a message to your brain telling it that is hot, which in turn causes your brain to turn on your body’s natural cooling system, sweating, to reduce your body’s core temperature. According to McNaughton, “The hot drink somehow has an effect on your systemic cooling mechanism, which exceeds its actual effect in terms of heating your body.” As such, it is not so much the components in tea that cause you to cool down, but rather the hot temperature of the tea that serves as a catalyst to activate your body’s sweating mechanism.
While drinking hot tea will help you cool down on a hot day in theory, there is a caveat to this cooling method. Ollie Jay, a researcher at University of Ottawa’s School of Human Kinetics explains, “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.” This idea collaborates the theory presented by McNaughton that the hot drink will increase your overall body temperature, but that this increase is more than compensated for by the amount you can decrease your body temperature by your sweat evaporating. All that sweat may seem annoying, but a large amount of sweat means more cooling.
The caveat is drinking hot tea on a hot day will only work if the extra sweat produced from drinking the tea is actually able to evaporate. If the extra sweat you produce can’t evaporate, you won’t feel any cooler. Jay states: “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 very 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, if you live in a climate where there are hot, dry days, drinking hot tea will likely help you cool down. However, if you live in a humid climate, you might want to stick with iced tea.
That’s Fine in Theory . . .
While I am not one to doubt the theories of acclaimed scientists, the fun part about doing a research experiment is being able to try it out for yourself. Thus, on a recent morning when I could already feel the temperature beginning to climb, I decided to sit down for a cup of hot tea. Interestingly, the tea didn’t cool me down, but it didn’t cause me to sweat excessively. Perhaps I’m not sensitive enough to the change in temperature or maybe it just wasn’t hot enough outside yet.
An alternative explanation could be that there is a psychological aspect to whether a hot or cold drink is the most effective method for cooling off when it is hot. Having grown up in the United States where cold drinks are practically de rigueur on hot days, I’ll be the first to admit I’m inclined to go for an iced tea in the summer. However, in many other countries, particularly ones that have consistently hot climates, quite the opposite is true and a hot drink is their go-to. Ultimately, neither approach would have gained popularity in their respective areas if they weren’t deemed at least somewhat effective. As such, it seems either option is acceptable. If you enjoy iced tea, brew it up by the gallon full using one of the many creative brew methods that are featured online during the summer. The same goes for hot tea, if you prefer your tea brewed this way, start your day with a piping cup. Or, if you are feeling brave, try drinking whichever tea you don’t usually drink and see if it makes a difference. As for me, I’ll continue to experiment and will be drinking my tea both hot and cold this summer.