炎炎夏日，热茶和冷饮哪个更降暑？

自打入伏以来，国内多地就开启了桑拿模式，气温直逼40度。吃冰棍喝冷饮，还是喝热茶，哪一种才是降暑的正确打开方式？

While you might be tempted to reach for a cold drink to help cool you down in such hot weather, surprisingly hot drinks such as teas and coffees may actually be more effective.

在这样的大热天，你也许很想喝杯冷饮来凉快一下，但令人惊讶的是，茶和咖啡等热饮可能对解暑更有效。

A study in 2017 by researchers from the University of Ottawa looked at the effect of drinking hot drinks on body temperature.

渥太华大学的科学家在2017年研究了喝热饮对于降低体温的效果。

The results revealed that a hot drink can cool you down, but only in dry conditions.

研究结果揭示，热饮可以让你感觉凉快，但只有在干燥的环境中才如此。

Speaking to the Smithsonian Mag, Dr Ollie Jay, one of the authors of the study, 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.”

在接受《史密森学会杂志》采访时，该研究的作者之一奥利·杰博士解释说：“如果喝热饮，体内储存的热量就会降低，前提是喝热茶时排出的汗水可以蒸发掉。”

Essentially, when you ingest a hot drink, you start sweating more. If the sweat is able to evaporate, it actually cools you down, more than compensating for the added heat to the body from the fluid.

基本原理是，当你喝热饮时，你会流更多汗，如果汗水能够蒸发掉，你就会感到凉爽，这个过程中降低的体温超过了热饮给你增加的体温。

While sweating can be embarrassing, it’s an essential body function to help keep us cool.

尽管流汗令人尴尬，但却是人体的一项重要功能，有助于保持凉爽。

As the sweat evaporates from the surface of your skin, it removes excess heat by converting the water from a liquid to a vapour.

当汗水从皮肤表面蒸发时，会在水转化为蒸汽的过程中带走多余的热量。

However, in humid conditions this cooling effect is less effective, so drinking hot drinks won’t help to cool you down.

但是，在潮湿的环境中，这种降温效果就没那么明显，因此在潮湿天气喝热饮也就不能帮助你解暑。

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.

杰博士解释说：“在闷热潮湿的天气，如果你穿着很多衣服，或者你汗如雨下，而且没有从皮肤表面蒸发掉，那么喝热饮就不利于解暑。”

"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.”

“热饮仍然会给身体增加一点热量，所以如果汗水无法蒸发，那就选择冷饮。”

Overall, the lesson learned is that in hot, dry conditions, drinking hot drinks will cool you down, but if you’re in a humid location, it’s best to stick to cold beverages.

总体而言，我们得到的结论是，在炎热干燥的天气里，喝热饮会让你感觉凉爽，但如果天气潮湿，最好还是喝冷饮。