每天8小时不是必需睡眠？

The idea that we should sleep in eight-hour chunks is relatively recent. The world’s population sleeps in various and surprising ways. Millions of Chinese workers continue to put their heads on their desks for a nap of an hour or so after lunch, for example, and daytime napping is common from India to Spain.

人应连睡八小时，这是相对较新的理念。在这个世界上，人们睡觉的方式千姿百态、令人惊讶。比如在中国，现在仍然有上百万人每天吃完午饭后，要趴在桌上打一个小时的盹。在从印度到西班牙的国家里，午睡都司空见惯。

One of the first signs that the emphasis on a straight eight-hour sleep had outlived its usefulness arose in the early 1990s, thanks to a history professor at Virginia Tech named A. Roger Ekirch, who spent hours investigating the history of the night and began to notice strange references to sleep. A character in the “Canterbury Tales,” for instance, decides to go back to bed after her “firste sleep.” A doctor in England wrote that the time between the “first sleep” and the “second sleep” was the best time for study and reflection. And one 16th-century French physician concluded that laborers were able to conceive more children because they waited until after their “first sleep” to make love. Professor Ekirch soon learned that he wasn’t the only one who was on to the historical existence of alternate sleep cycles. In a fluke of history, Thomas A. Wehr, a psychiatrist then working at the National Institute of Mental Health in Bethesda, Md., was conducting an experiment in which subjects were deprived of artificial light. Without the illumination and distraction from light bulbs, televisions or computers, the subjects slept through the night, at least at first. But, after a while, Dr. Wehr noticed that subjects began to wake up a little after midnight, lie awake for a couple of hours, and then drift back to sleep again, in the same pattern of segmented sleep that Professor Ekirch saw referenced in historical records and early works of literature.

在20世纪90年代初，第一次有人指出连续八小时睡眠是个过时的概念，提出这个想法的是弗吉尼亚理工学院(Virginia Tech)的历史学教授A·罗杰·埃克奇(A. Roger Ekirch)，他花了大量时间翻查关于夜晚的史料，结果发现古人在谈到睡眠时会做出一些奇怪的表述。比方说，在《坎特伯雷故事集》(Canterbury Tales)里，当中的一个人物决定在睡了“第一觉”后回到床上再躺一下。而英国的一位医生写道，在“第一觉”和“第二觉”中间的这段时间，用于学习和思考再合适不过。还有一位16世纪的医生认为，做苦力的人之所以能多生几个孩子，是因为他们要等睡过了“第一觉”后再做爱。埃克奇教授很快发现，他不是唯一一个发现交替睡眠周期由来以久的人。当时在马里兰州贝塞斯达的美国国家心理健康研究院(National Institute of Mental Health)担任精神病学专家的托马斯·A·韦尔(Thomas A. Wehr)进行了一项实验，参与者不得使用人造光源。由于没有了电灯、电视或电脑这些产品的照明与干扰，参与试验的人只能在夜里呼呼大睡——至少一开始是这样的。但过了一阵子，到了午夜过后，韦尔发现参与者纷纷醒来，他们在床上醒着躺了几个钟头，然后重新睡去，这样断断续续的睡眠周期，与埃克奇教授从史料和早期文献中发现的例证是一样的。

It seemed that, given a chance to be free of modern life, the body would naturally settle into a split sleep schedule. Subjects grew to like experiencing nighttime in a new way. Once they broke their conception of what form sleep should come in, they looked forward to the time in the middle of the night as a chance for deep thinking of all kinds, whether in the form of self-reflection, getting a jump on the next day or amorous activity. Most of us, however, do not treat middle-of-the-night awakenings as a sign of a normal, functioning brain.

看起来，如果得到一个远离现代生活的机会，我们的身体能够自然而然地适应片断式的睡眠节奏。参加实验的人渐渐喜欢上了用一种新的方式来感受夜晚。一旦他们打破了关于睡眠形式的既有观念，就会期待着能趁着午夜时分来进行沉思，不管他们是用这段时间来进行反思、为第二天做好准备、还是想感情方面的事情。不过，我们中的大部分人都觉得在子夜时分醒来，不能算是大脑运行如常的信号。

Robert Stickgold, a professor of psychiatry at Harvard Medical School, proposes that sleep — including short naps that include deep sleep — offers our brains the chance to decide what new information to keep and what to toss. That could be one reason our dreams are laden with strange plots and characters, a result of the brain’s trying to find connections between what it’s recently learned and what is stored in our long-term memory. Rapid eye movement sleep — so named because researchers who discovered this sleep stage were astonished to see the fluttering eyelids of sleeping subjects — is the only phase of sleep during which the brain is as active as it is when we are fully conscious, and seems to offer our brains the best chance to come up with new ideas and hone recently acquired skills. When we awaken, our minds are often better able to make connections that were hidden in the jumble of information.

哈佛大学医学院的精神病学教授罗伯特·斯蒂克戈尔德(Robert Stickgold)认为，睡眠——包括产生了深度睡眠的小睡——会让我们的大脑得到一个机会去决定新的信息孰去孰留。正因为此，我们的梦才充斥着奇怪的情节与人物，这是因为我们的大脑此时正在试图寻找最近学到的新东西与存储在长期记忆中的知识之间存在的关联。快速眼动睡眠——之所以叫这个名字，是因为发现了这个睡眠阶段的研究者很惊异地看到睡觉的人眼皮在急速颤动——是整个睡眠中唯一一个大脑跟完全清醒时同样保持活动的阶段，而且这种睡眠阶段看来能为大脑提供一个孕育新想法，磨炼近期学会的技能的良机。等到醒来时，我们往往更有能力在错综复杂的信息中发现隐秘的联系。

Gradual acceptance of the notion that sequential sleep hours are not essential for high-level job performance has led to increased workplace tolerance for napping and other alternate daily schedules.

连睡几个小时并不是高水平工作表现的必要条件，在渐渐接受了这个概念后，企业也越来越能包容员工在工作场所打盹，或采取其他类似的间断工作节奏。