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Even though shouts of “You’ve got B.O. (short for body odor) !” at a school playground might cause the scientifically minded to reply, “Of course, we all do!” The fact remains that when people talk about body odor they’re speaking of the unpleasant, sometimes eye-watering kind found in a football team’s locker room at game’s end. Or at far too many convention halls.
So what is it that causes the body to smell like an unwashed elephant from time to time? The answer that immediately springs to mind3 is, of course, sweat. But that’s only a part of the story. Sweat, on its own, is odorless. The smell that betrays us on first dates and job interviews is actually a product of digestion. And it’s not from our stomachs.
虽然在听到学校操场上的喊声“你有体味（B.O. 是英语“体味”的缩写）！”时，稍有科学常识的人都会回答：“当然了，每个人都有！”但是当人们谈及体味时，他们指的是类似于一场比赛结束后足球队更衣室里那种令人不快的、有时熏得人直掉泪的味道。许多会议厅里也会有这种气味。
那么，是什么使得人体会时不时地散发出闻起来像没洗过澡的大象的气味呢？我们脑海中立即涌现的答案是：当然是汗液了。但这只是部分原因。汗液本身是没有味道的。那些在我们初次约会和工作面试中背叛我们的气味实际上是“消化”的产物。然而这种“消化”并非来自我们的胃。
Sweat is produced by two different glands4. Eccrine glands cover most of the body and produce sweat consisting mainly of electrolytes and water, which cools the body when it evaporates from the skin.5
Apocrine glands are found in the groin, hands, feet and underarms.6 These glands produce sweat that contains proteins and fatty acids, which makes the perspiration thicker and milky or yellowish in color.7 This is where the sweat stains you see on light-colored shirts come from. While eccrine glands are activated8 as part of the body’s cooling system, apocrine glands can produce sweat when the body is experiencing anxiety, nervousness or stress.
When it first appears on our skin, sweat is just a fluid without an odor. But the bacteria on our bodies are particularly attracted to the proteins in apocrine sweat which they eat, digest and expel as highly-aromatic fatty acids.9 These include the notorious (and notoriously named) (E)-3-methyl-2-hexenoic acid. The process typically takes about an hour.
It doesn’t help that the apocrine glands are found in the moist, dark areas of the body—exactly the neighborhoods in which odor-producing bacteria like micrococci10 enjoy living. When we wrap our feet in socks and leather shoes, we not only create a haven for bacteria, but for fungi as well, which is why our foot odor can be particularly troublesome and different in character from underarm smells.11
体味产生的缘由
汗液是由两种不同的腺产生的。小汗腺几乎遍布体表，产生的汗液主要包含电解质和水，汗液从皮肤上蒸发时能够降低体温。
大汗腺分布在腹股沟、手脚和腋窝。大汗腺产生的汗液中包含蛋白质和脂肪酸，使得汗液变得粘稠，颜色变成乳白色或淡黄色。这就是为什么你会在浅颜色的衬衫上看到汗渍的原因。小汗腺是身体冷却机制的一部分，而当你感到焦虑、紧张或压力的时候产生的汗液则是大汗腺的“功劳”。
当汗液最初出现在皮肤表面时，是没有气味的液体。但我们身体上的细菌特别喜欢大汗腺分泌的汗液中的蛋白质，它们吞噬并消化蛋白质，然后排出具有浓烈气味的脂肪酸。其中包括声名狼藉的（也因此得了个臭名的）(E)-3-甲基-2-己烯酸。这个过程一般需要一个小时左右。
即使大汗腺分布在身体潮湿、幽暗之处也无济于事，因为这些地方正是微球菌等产生气味的细菌喜欢滋生的部位。当我们为脚套上袜子和皮鞋时，我们不仅为细菌，也为真菌提供了庇护所，这就是为什么脚气特别令人讨厌，并且本质上与腋下的气味有所不同。
Most body odor can be banished with simple hygiene techniques.14
Scientists assert that one reason our unpleasant smells come from hair-packed areas on our bodies is because at one time, just like animals, humans used scent to broadcast the pheromones15 in our sweat to attract mates. When that scent got tangled16 in our hair, it stuck around longer.
Fortunately, we now use a host of other scents to make ourselves appealing to the opposite sex, but that doesn’t mean odors still don’t get trapped in our body hair. So one simple solution to persistent B.O. is to trim the hair in odor-producing regions such as the underarms.
Another is bathing. Because it takes bacteria about an hour to digest the proteins in our apocrine sweat, the sooner we wash it away, the less chance there will be for mini-stink factories to begin churning out their exhaust.17 In addition to bathing our bodies, sweaty clothes should be washed frequently as well. S
So what is it that causes the body to smell like an unwashed elephant from time to time? The answer that immediately springs to mind3 is, of course, sweat. But that’s only a part of the story. Sweat, on its own, is odorless. The smell that betrays us on first dates and job interviews is actually a product of digestion. And it’s not from our stomachs.
虽然在听到学校操场上的喊声“你有体味（B.O. 是英语“体味”的缩写）！”时，稍有科学常识的人都会回答：“当然了，每个人都有！”但是当人们谈及体味时，他们指的是类似于一场比赛结束后足球队更衣室里那种令人不快的、有时熏得人直掉泪的味道。许多会议厅里也会有这种气味。
那么，是什么使得人体会时不时地散发出闻起来像没洗过澡的大象的气味呢？我们脑海中立即涌现的答案是：当然是汗液了。但这只是部分原因。汗液本身是没有味道的。那些在我们初次约会和工作面试中背叛我们的气味实际上是“消化”的产物。然而这种“消化”并非来自我们的胃。
Sweat is produced by two different glands4. Eccrine glands cover most of the body and produce sweat consisting mainly of electrolytes and water, which cools the body when it evaporates from the skin.5
Apocrine glands are found in the groin, hands, feet and underarms.6 These glands produce sweat that contains proteins and fatty acids, which makes the perspiration thicker and milky or yellowish in color.7 This is where the sweat stains you see on light-colored shirts come from. While eccrine glands are activated8 as part of the body’s cooling system, apocrine glands can produce sweat when the body is experiencing anxiety, nervousness or stress.
When it first appears on our skin, sweat is just a fluid without an odor. But the bacteria on our bodies are particularly attracted to the proteins in apocrine sweat which they eat, digest and expel as highly-aromatic fatty acids.9 These include the notorious (and notoriously named) (E)-3-methyl-2-hexenoic acid. The process typically takes about an hour.
It doesn’t help that the apocrine glands are found in the moist, dark areas of the body—exactly the neighborhoods in which odor-producing bacteria like micrococci10 enjoy living. When we wrap our feet in socks and leather shoes, we not only create a haven for bacteria, but for fungi as well, which is why our foot odor can be particularly troublesome and different in character from underarm smells.11
体味产生的缘由
汗液是由两种不同的腺产生的。小汗腺几乎遍布体表，产生的汗液主要包含电解质和水，汗液从皮肤上蒸发时能够降低体温。
大汗腺分布在腹股沟、手脚和腋窝。大汗腺产生的汗液中包含蛋白质和脂肪酸，使得汗液变得粘稠，颜色变成乳白色或淡黄色。这就是为什么你会在浅颜色的衬衫上看到汗渍的原因。小汗腺是身体冷却机制的一部分，而当你感到焦虑、紧张或压力的时候产生的汗液则是大汗腺的“功劳”。
当汗液最初出现在皮肤表面时，是没有气味的液体。但我们身体上的细菌特别喜欢大汗腺分泌的汗液中的蛋白质，它们吞噬并消化蛋白质，然后排出具有浓烈气味的脂肪酸。其中包括声名狼藉的（也因此得了个臭名的）(E)-3-甲基-2-己烯酸。这个过程一般需要一个小时左右。
即使大汗腺分布在身体潮湿、幽暗之处也无济于事，因为这些地方正是微球菌等产生气味的细菌喜欢滋生的部位。当我们为脚套上袜子和皮鞋时，我们不仅为细菌，也为真菌提供了庇护所，这就是为什么脚气特别令人讨厌，并且本质上与腋下的气味有所不同。
Most body odor can be banished with simple hygiene techniques.14
Scientists assert that one reason our unpleasant smells come from hair-packed areas on our bodies is because at one time, just like animals, humans used scent to broadcast the pheromones15 in our sweat to attract mates. When that scent got tangled16 in our hair, it stuck around longer.
Fortunately, we now use a host of other scents to make ourselves appealing to the opposite sex, but that doesn’t mean odors still don’t get trapped in our body hair. So one simple solution to persistent B.O. is to trim the hair in odor-producing regions such as the underarms.
Another is bathing. Because it takes bacteria about an hour to digest the proteins in our apocrine sweat, the sooner we wash it away, the less chance there will be for mini-stink factories to begin churning out their exhaust.17 In addition to bathing our bodies, sweaty clothes should be washed frequently as well. S