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.

 

 

　　为何我们的汗水不好闻？

 

　　我们的身体主要有两种汗腺。一种汗腺几乎遍布全身，其流出的汗水是干净无味的，含水量超过99%。当这种汗水冲洗你的皮肤时，它通过蒸发作用给你的身体降温，甚至有时候还扮演“义务清洁员”的角色，将你皮肤表面的有害细菌清洗掉。

 

　　但是人体内还存在另一种汗腺，它分布在腋窝、腹股沟和乳头附近。这种汗腺会产生大量粘稠的汗水，这些汗水还是某些细菌的美食。当喜好汗水的细菌在享受它们的美食时，这些部位的汗水的气味会变得更重。这就是为什么你出汗的时间越长，你身上的汗臭味越重的原因。

 

　　就像第一种汗腺有清爽和清洁人体的功能一样，这种粘稠的汗液在进化史上也有它的作用。对于其它的哺乳类动物来说，浓重的汗水味可以代表它的个体身份和性魅力指数。但是这种社交手段在人类身上还适用吗？事实上有证据显示，一切皆有可能！