不管怎样，请保持睡眠八小时

At this point we should all know that we need to get eight hours of sleep per night. Any less and you’re functioning below normal. But what about more? Is it possible to get too much rest?

我们都应该知道我们需要每晚睡八小时，少了，日常机能就会低于正常水平。但是睡多了呢?有可能得到更多休息吗?

A new study suggests that yes, getting nine or more hours of sleep per night might also be unhealthy. Researchers from around the world gathered data from 116,632 people in 21 countries, each of whom they followed for about 7.8 years to see whether the amount they slept correlated with their overall risk of mortality (their likelihood of dying during the course of the study). They published their results in the European Heart Journal, which showed what epidemiologists call a J-shaped curve. The phenomenon refers to there being a point in a graph of mortality where the risk is minimized. In this case, that’d be right around eight hours of sleep. As you head down on the chart toward fewer hours of sleep, the risk of death increases for a whole host of reasons, but there’s also a rising risk as you increase the amount of sleep. And they’re not the only ones to find the J-shape. Other studies have also found that people who get nine or more hours of rest each night seem to have higher rates of mortality,

一项新研究指出，每晚睡9小时或更多对健康也是有害的。来自世界各地的研究人员收集了来自21个国家的116632人的数据，他们每个人都被追踪了大约7、8年，看他们的睡眠量是否与他们的整体死亡风险(他们在研究过程中死亡的可能性)相关。他们将结果发表在《欧洲心脏杂志》上，结果显示了流行病学家所称的“J形”曲线。这种现象现实在死亡风险最小化的地方有一个点。在这种情况下，这个点是大约8小时的睡眠。当你在图表上往更少的睡眠时间看去时，死亡的风险会因各种原因而增加，但随着你增加睡眠量，风险也会增加。而且受试者数据并不是唯一显示J形的，其他研究还发现，每晚睡九小时或更长时间的人似乎死亡率更高。

But that doesn’t necessarily mean that more sleep is causing more death. Sometimes a curve is J-shaped because of some other confounding factor.

但这并不一定意味着更多的睡眠会导致更高的死亡风险，某些其他混杂因素也会让曲线呈J形。

Think of an adult you know who sleeps 10 hours a day. Is that a healthy person? Probably not. Experts like Matthew Walker, the director of the sleep and neuroimaging lab at the University of California, Berkeley, have discussed how various diseases and chronic ailments might prompt someone to sleep more yet also put them at higher risk of death. He discusses studies like this one in his book, Why We Sleep, in which he points out that “should you explore those studies in detail, you learn that the causes of death in individuals sleeping nine hours or longer include infection (e.g., pneumonia) and immune-activating cancers.” Serious illnesses like these prompt a person to sleep more, he points out, and thus “the illusion created is that too much sleep leads to an early death, rather than the more tenable conclusion that the sickness was just too much despite all efforts to the contrary from the beneficial sleep extension.”

想想你认识的盆友里每天睡10个小时的人，这是一个健康的人吗?可能不是。加州大学伯克利分校睡眠和神经影像实验室主任Matthew Walker讨论了各种疾病和慢性疾病如何促使人睡得更多，同时也使他们面临更高的死亡风险。他在他的书《我们为什么要睡觉》中讨论了这样的研究，他在其中指出，“如果详细探讨这些研究，会发现睡眠9小时或更长时间的人的死亡原因包括感染(如肺炎)。像这样的严重疾病促使一个人睡得更多，因此会让人觉得，过多的睡眠会导致早逝，而不是更为可靠的结论，尽管有益的睡眠让你更健康，但是疾病带来的负面影响太多了。“

The researchers who ran this most recent study were well aware of this criticism, and so went to impressive lengths to try to prevent the confounding factor of illness. They tried eliminating people who had any symptoms that might hint at underlying disease from the analysis, as well as those who already had a diagnosed illness, and found similar results. That could be a sign that there really is something about sleeping more that’s unhealthy for us. But it’s also important to note that even these researchers note “causality cannot be definitively proven from this or other observational studies.” Observational studies are great for looking at large populations on whom you can’t do detailed sleep analyses, but they’re simply not able to draw conclusions about whether one factor caused another.

进行这项最新研究的研究人员非常清楚这种批评，因此为了防止混淆的疾病因素，他们付出了巨大的努力。他们试图从分析中消除那些可能包含潜在疾病症状的人，以及那些已经确诊患病的人，并发现了类似的结果。这可能是一个迹象，表明确实存在一些关于睡眠的误解，这对我们来说是不健康的。但同样重要的是，即使这些研究人员也注意到“这种或其他观察性研究无法明确证实因果关系。”观察性研究非常适合观察无法进行详细睡眠分析的大群体，但它们只是简单的观察，无法得出关于一个因素是否导致另一个因素的因果性的结论。

To figure that out, you need to do some kind of randomized study. That would mean prescribing groups to sleep a certain amount for many years and following them to see what happened, which is probably not feasible. Barring that, researchers would need to figure out a plausible mechanism by which sleep would increase risk of death. Cigarettes, for example, were never prescribed to people who were then followed in lengthy, randomized studies. Scientists had to do other, more clever experiments to figure out how the components of cigarettes were impacting the human body and use that evidence to draw conclusions from observational data.

要弄明白这一点，需要做一些随机研究。这意味着受试群体要睡足一定量多年并跟踪他们，看看发生了什么，这大概是不可行的。除此之外，研究人员需要找出一种合理的机制证明睡眠过多会增加死亡风险。例如，吸烟从未纳入对研究的影响。科学家们不得不做其他更巧妙的实验来弄清楚烟草成分如何影响人体，并利用这些证据从观察数据中得出结论。

So far, though, Walker writes that “no biological mechanisms that show sleep to be in any way harmful have been discovered.” That doesn’t mean they won’t be in the future—maybe we will find a mechanism. It’s just that right now it’s not clear how 9.5 hours of sleep versus 8 would negatively impact a person.

然而，到目前为止，Walker写道“没有发现任何显示睡眠有害的生物机制。”这并不意味着将来不会 - 也许我们会找到一种机制。但现在就是这样，目前尚不清楚9.5小时的睡眠与8小时会对一个人产生负面影响。

Statistics would also suggest that far more Americans should be concerned with not getting enough sleep than with getting too much. A 2013 Gallup poll showed that 40 percent of Americans regularly sleep six hours or less per night, whereas only five percent get nine-plus hours. Part of the problem with chronic sleep deprivation is that you don’t realize how sleep-deprived you are while you’re sleep-deprived. Researchers have tested this by monitoring people in sleep labs and having them sleep eight hours per night, then six hours another night, and having them take the same test after each. When asked how they think they did after only sleeping for six hours, people say they did great, probably just as well as they did when fully recharged. In reality, they did significantly worse. They just didn’t realize it.

统计数据还表明，更多的美国人应该关注的是睡眠不足而不是过多。2013年盖洛普民意调查显示，40%的美国人每晚经常睡6个小时或更少，而只有5%的人每天睡9个小时。慢性睡眠剥夺的部分问题在于，你没有意识到在睡眠不足时你的睡眠不足。 研究人员通过监测睡眠实验中的人并让他们每晚睡8小时，然后每晚睡6小时，并让他们在每次睡眠后进行相同的测试。当被问及他们认为他们只睡了六个小时之后他们是怎么想的时候，人们说他们感觉很好，可能和完全睡饱一样好。但实际上，他们的表现要差得多，而他们只是没有意识到这一点。

So if you’re one of those people who claims they only need six hours, don’t use this study to prove how it’s just as bad to get too much sleep. The jury is still out on how surplus sleep could hurt you, but it is most definitely in on how harmful it is to be chronically sleep-deprived. Aim for eight hours every single night, regardless of how much you think you need. And if you’re consistently sleeping more than nine or ten hours a night, go see a doctor to make sure you don’t have some underlying condition or a sleep disorder. You may be perfectly fine, but you never know.

因此，如果你是那些声称只需要六个小时的人之一，那么就不要用这项研究来证明睡眠太多也是如此糟糕。研究团队仍然没有搞清楚多余的睡眠会对你造成什么伤害，但长期睡眠不足绝对会对你有很大的伤害。无论你认为自己需要多少睡眠，请每晚尝试睡8小时。如果你每晚睡眠时间超过九或十个小时，那就去看医生，确保你没有某些潜在的病症或睡眠障碍。你可能感觉很好，但你永远不知道是不是这样。