英語聽力文摘557 為何我們的汗水不好聞？

Our bodies have two main kinds of sweat glands. The sweat glands that are distributed over most of the body produce an innocent, clear sweat that’s more than ninety-nine percent water. As this watery sweat rinses your skin, it cools the body by evaporation–and even performs a community service by rinsing away potentially stinky bacteria!

But there’s another type of sweat gland located only in the armpits, groin, and around the nipples. These sweat glands produce a thicker, cloudier sweat that’s a favorite food of certain bacteria. And once these sweat-loving bacteria really start chowing down, they make the smell of the sweat on these parts of the body even stronger. That’s why the longer you’re sweaty, the stinkier you get.

Like the first type of sweat glands which cool and cleanse the body, these stinkier sweat glands also have an evolutionary function. For other mammals, this potent sweat speaks volumes about an individual’s identity and level of sexual interest. But does it still serve the same social purpose for humans? In fact, there is some evidence that it does.

　　為何我們的汗水不好聞?

　　我們的身體主要有兩種汗腺。一種汗腺幾乎遍布全身，其流出的汗水是干凈無味的，含水量超過99%。當這種汗水沖洗你的皮膚時，它通過蒸發(fā)作用給你的身體降溫，甚至有時候還扮演“義務清潔員”的角色，將你皮膚表面的有害細菌清洗掉。

　　但是人體內還存在另一種汗腺，它分布在腋窩、腹股溝和乳頭附近。這種汗腺會產生大量粘稠的汗水，這些汗水還是某些細菌的美食。當喜好汗水的細菌在享受它們的美食時，這些部位的汗水的氣味會變得更重。這就是為什么你出汗的時間越長，你身上的汗臭味越重的原因。

　　就像第一種汗腺有清爽和清潔人體的功能一樣，這種粘稠的汗液在進化史上也有它的作用。對于其它的哺乳類動物來說，濃重的汗水味可以代表它的個體身份和性魅力指數。但是這種社交手段在人類身上還適用嗎?事實上有證據顯示，一切皆有可能!