大熱天喝熱飲有助散熱?

Does Drinking Something Hot On A Hot Day Cool You Down?

大熱天喝熱飲有助散熱？

One common factoid that has been circulating the internet recently is that drinking a hot beverage on a hot day will cool you down. Some immediately dismiss the claim while others swear by it.

最近網上瘋傳在熱天喝熱飲能散熱的言論。對此，有些人立馬錶示否定，而另一些人則表示強烈支持。

But who is right? Is there any actual scientific evidence behind this seemingly counter-intuitive claim?

究竟哪一方是對的呢？這個看似反常理的言論究竟有無科學依據？

Drinking something hot on a hot day can indeed cool you down, but there is a catch. A study done at the University of Ottawa's School of Human Kinetics showed that if you were to drink a hot beverage in a hot and dry environment, your body will overcompensate for the added heat by sweating, and sweating a lot. It's this excessive sweating that causes your body to cool down, and cooling it down more than if you had drank something cold instead.

熱天喝熱飲的確能降溫，但這也是有條件的。渥太華大學人類動力學院曾做過相關實驗，結果表明，如果在炎熱乾燥的環境下喝熱飲，身體會通過流汗代謝多餘熱量。這些多排出的汗會讓你身體涼爽下來，比喝冷飲效果要好。

However, this cooling effect only works if the air is dry, rather than humid. You cannot sweat efficiently enough to take advantage of the benefit in a muggy or humid environment.

但這個冷卻效果只在乾燥空氣下才有用。在悶熱潮溼環境下完全不管用。

You may have already experienced this effect when eating hot or spicy foods. Research at the University of Cambridge discovered that one specific receptor, the TRPV1 receptor, was responsible for sensing heat and telling our body how to respond. In many individuals, the response is to produce excessive sweat.

吃很辣或者很燙的食物也會有此效果。劍橋大學的實驗表明，人體有種叫trpv1的受體，主要負責感知熱力，並且告訴你的身體如何反應。大多數人的反應都是流汗。

If the air around you is dry and you're wearing light clothes, eating foods spicy enough to cause a sweating reaction will also produce the same cooling effect as drinking a hot beverage.

如果周遭環境乾燥，你又穿着很薄的衣服，吃辣的食物會引發流汗，跟喝熱飲的效果一樣。

So to recap, this myth isn't a myth at all. Drinking something hot can in fact cool you down if the right conditions are met.

綜上所述，這個說法其實符合常理。如果條件合適，喝熱飲的確能給身體降溫。

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