黑执事第二季名字:女人出汗与男人有何不同？

Does a hard-working woman sweat like a man? That question, which has figured in many an antiperspirant commercial, has received surprisingly little scientific scrutiny. But a new study published this month in the journal Experimental Physiology provides persuasive evidence that women do sweat copiously during exercise. (Did anyone really believe they misted?) But fit women seem to sweat differently than unfit people of either sex, and quite differently than fit men, a fact that has implications for sports performance. It also may have some bearing on what it has meant, since prehistory, to be female.

一个勤奋工作的妇女出的汗像男人一样多吗？这个在很多止汗剂广告中出现的问题，却很少经过科学的研究。但这个月发表在实验生理学学报上的一项新研究提供了充分的证据表明在锻炼时，女性会出很多汗(有谁真的相信吗？)。但健康的女性出汗不仅不同于不健康的男性和女性，更不同于健康的男性。这可能说明了运动量的不同。也可能与作为女人有关。

For the study, researchers at Osaka International University and Kobe University in Japan recruited a pool of trained athletes, male and female, as well as an age- and gender-matched group of untrained volunteers. The men and women in the two groups were similar in terms of weight. All of the volunteers rode stationary bikes in a physiology lab heated to a balmy 86 degrees. The beginning of the hourlong session was leisurely; the pedaling intensity was only about 30 percent of each volunteer’s maximal oxygen capacity (VO2max). Then it became tougher, rising to 50 percent of each rider’s VO2 max, while the final 20 minutes required that the riders work at a strenuous 65 percent of his or her VO2 max. Throughout, researchers monitored how much perspiration the cyclists were producing on their foreheads, chests, backs, forearms and thighs. The researchers also determined how many sweat glands were active during each rider’s session. A person’s overall sweat rate depends on how many sweat glands his or her body activates and how much sweat is excreted at each gland.

为了研究的准确性，日本大版国际大学和神户大学的研究人员找了一组经过训练的男女运动员，一组没有经过训练的普通志愿者。两组人的年龄和性别比例保持一致。两组中同性别的人体重也差不多。所有的志愿者都在一个温暖的(室内温度在86华氏[30摄氏])实验室中骑固定自行车。在刚开始的一个小时内，所有人都比较轻松。运动强度只达到每个人最大耗氧量的30%。接下来就更累了，强度提高到每个人最大耗氧量的50%。最后20分钟，所有人的运动强度都达到了最大耗氧量的65%。在整个过程中，研人员监控了志愿者额头，胸部，背部，前臂和大腿上的出汗量，还确定了每个人在骑车过程中有多少汗腺在活跃。一个人的出汗率取决于汗腺的活跃数和每个汗腺的排汗量。

What the researchers found was that the fit men, unsurprisingly, perspired the most, significantly more than the fit women, especially during the more intense exercise. But the athletic men weren’t using more sweat glands. The fit women had just as many glands active and pumping; they produced less sweat from each gland. Meanwhile, the unfit women, by a wide margin, perspired the least, especially during the strenuous cycling, and became physiologically hotter — their core temperatures rising notably — before they began to sweat at full capacity. These results, the scientists concluded, “revealed a sex difference in the effects of physical training on the sweating response” and, just as important, “a sex difference” in “the control of sweating rate to an increase in exercise intensity.” In other words, the women, whether fit or not, were less adept of ridding themselves of body heat by drenching themselves in sweat.

研究人员发现，健康的男性毫无疑问出汗最多，远远超过健康的女性，特别是在运动强度加大之后。但这些男运动员并没有使用更多的汗腺，健康的女性活跃的汗腺一样多，她们每个汗腺排汗较少。同时，不健康的女性出汗最少，特别是在费力骑行的时候，她们先是体温显著升高，然后才开始大量的流汗。科学家推断，实验结果显示了“体育锻炼对出汗反应影响的性别差异”，同样也说明“两性在运动强度加大时控制自己身体出汗能力的不同”。换句话说，不管是健康的还是不健康的，女性更不善于通过出汗来降低自己的体温。

Sweating is one of those bodily functions that seem uncomplicated, but it remains not fully understood by physiologists, at least in terms of how (and why) gender affects the process. “We know that fitness changes the sweating response,” said Timothy Cable, Ph.D., a professor of exercise physiology at John Moores University in Liverpool, England, who has extensively studied female athletes and how they perspire. As someone becomes more fit, his or her body begins to sweat at a lower body temperature. This is important, because “the body has a critical core temperature,” Dr. Cable said, which occurs at about 104 degrees, after which the brain simply “shuts down the motor cortex.” Unbidden, your legs stop churning and you curl up on the sidewalk until your core temperature drops (or a kind passerby calls 911). Sweating delays the onset of this critical heat buildup by dissipating the excess heat through evaporation. If you start to sweat at a lower temperature and increase your sweating rate as you get hotter during hard exercise, you’re less likely to reach the critical temperature.

出汗是那些看似简单的生理机能之一，但生理学家仍然没有充分理解它，至少在为什么性别会影响出汗这个问题上。“我们知道身体的健康度会影响人出汗”，英国利物浦约翰摩尔斯大学运动生理学教授Timothy Cable博士说。他广泛的研究了女性运动员是如何出汗的。当某人变得更加健康时，他在体温比较低的时候就开始流汗。这是非常重要的，因为人体有一个临界温度，Cable博士说，大概在104华氏(40摄氏度)，超过这个温度之后，大脑就会关闭大脑皮层的活动。突然，你的腿就不能动了，只能蜷缩在人行道上直到体温下降到临界温度，或者等路过的人打911。而通过汗液蒸发，可以散发多余的热量，从而延缓临界温度的到达。如果你在体温较低的时候就开始出汗，而且在剧烈运动中随着体温的升高会加大身体排汗量，你就不容易到达临界温度。

Scientists learned all that long ago. But they have yet to explain why women, even the fittest, don’t sweat as much as men, especially when they exercise at a high intensity. One answer, not yet definitively proved, seems to be “testosterone,” Dr. Cable said. Earlier studies suggest that the sweat rates of prepubertal boys and girls are roughly the same. Things begin to change when the sex hormones begin to circulate. Even then, men’s and women’s perspiration is similar in terms of water, salt content and smell, Dr. Cable said, strange as that may seem to anyone who’s been in close proximity to a young male athlete’s laundry hamper. (Sweat itself is odorless; the distinctive smell associated with sweating is produced by the waste products of bacteria feeding on the perspiration.) In an experiment conducted decades ago, male athletes were injected with estrogen and sweated less during subsequent exercise.

科学家很久之前就知道（这种现象）了，但他们还没有解释为什么女性，即使是最健康的女性，也没有男性流汗多，特别是在高强度锻炼中。“一个未经证实的原因是睾酮素”，Cable博士说。此前的研究表明，青年期男孩和女孩的出汗率大致相同。当性激素开始流通之后，情况才会发生变化。即使这时，男人和女人汗液的水含量、盐含量和味道也是相似的，Cable博士说，只有年轻男性运动员的汗液会有独特的味道。(汗本身没有味道，独特的味道来自于生长在汗液中细菌)。在一项十多年前的实验中，男性运动员被注射了雌激素，在接下来的锻炼中汗就流得少了。

But does this difference in sweating rates, whatever its cause, have practical implications? “It appears,” said Yoshimitsu Inoue, Ph.D., a professor of physiology at Osaka International University and one of the authors of the study, “that women are at a disadvantage when they need to sweat a lot during exercise in hot conditions.” On the other hand, it may be that women, during evolution, had the good sense to get out of the hot sun, and their bodies adapted accordingly. The “lower sweat loss in women may be an adaptation strategy that attaches great importance” to preserving body fluids “for survival,” he wrote in an e-mail, while “the higher sweat rate of men may be an adaptation strategy for greater efficiency of action or labor.”

但出汗率的差别，不管是因为什么，有什么实际意义吗？“看起来，”大阪国际大学生理学教授Yoshimitsu Inoue博士说，他也是这次研究的作者,“在热的环境中锻炼时，女性无法流很多汗，这是对其不利的因素”。而从另一方面说，这可能是女性在进化过程中，能有意识的避免烈日暴晒，从而相应地调整了自己身体的进化。女性低流汗率是一个重要的进化适应策略以防止体液流失，他在邮件中写到，而男性的高流汗率是使干活更有效率的进化策略。

Dr. Cable agreed. “Prehistoric men followed the herds,” he said, whatever the temperature, while the women, cleverly, sought out the shade. “It’s not a bad survival strategy,” he said, even today.

Cable博士同意这种说法。“不管气温多高，史前男性会跟着牲畜，”他说，“而女性则会去找阴凉处躲避”。“即使在今天，这种生存策略也不错”，他说道。

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