睡眠与健康|《BBC》：关于睡眠，你应知道的十件事儿
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本期导读：睡眠是一种在哺乳动物、鸟类和鱼类等生物中普遍存在的自然休息状态，甚至在无脊椎动物，例如果蝇中也有这种现象。睡眠的特征包括：减少主动的身体运动，对外界刺激反应减弱，增强同化作用（生产细胞结构），以及降低异化作用水平（分解细胞结构）。在人类、哺乳动物及其他很多已经被研究的动物，如鱼、鸟、老鼠、苍蝇中，规律的睡眠是生存的前提。对于人，睡眠占了人生的三分之一。
10 things to know about sleep as the clocks go back
随着冬令时的到来，关于睡眠，你需要知道的十件事儿
People across the UK will wake up having gained an hour's sleep on Sunday morning, as the clocks go back heralding darker evenings and shorter days. But how much do we know about sleep and its impact on our lives, from our health and mood, to how long we'll live?
英国的民众，这个周日进入了冬令时，早上也就能多睡一个小时了。随着进入冬令时，夜晚会早来，白天会变短，不过，关于睡眠以及睡眠对我们生活的影响，包括对我们的健康和情绪乃至我们寿命的影响，对此，我们都有什么样的了解呢？
1. We're told to get our eight hours
1. 我们被告知需要睡足8个小时
We often hear that we should all be getting eight hours' sleep a night. Organisations from the NHS to the US National Sleep Foundation recommend it. But where does this advice come from?
我们经常听到，我们所有人，晚上睡觉，都应睡够8个小时。各个组织机构，从英国的国家医疗服务署到美国的国家睡眠基金会，都建议睡8个小时。不过，这样的建议，从何而来呢？
Studies carried out around the world, looking at how often diseases occur in different groups of people across a population, have come to the same conclusion: both short sleepers and long sleepers are more likely to have a range of diseases, and to live shorter lives.
世界范围内针对人口中不同群体的疾病发生率所进行的各项研究也得出了相同的结论：睡眠不足的人和睡眠过度的人，都更易患上系列疾病，寿命也会更短。
But it's hard to tell whether it is short sleep that is causing disease or whether it is a symptom of a less healthy lifestyle.
但是，也很难说得清，到底是睡眠不足，还是不健康的生活方式，导致了疾病的发生。
Short sleepers are generally defined as those who regularly get less than six hours' sleep and long sleepers generally more than nine or 10 hours' a night.
睡眠不足的人，一般是指睡眠经常少于6个小时的人，而睡眠过度的人，一般是指每晚睡眠超过9或10个小时的人。
Pre-puberty, children are recommended to get as much as 11 hours' sleep a night, however, and up to 18 hours a day for newborn babies. Teenagers should sleep for up to 10 hours a night.
青春期前的孩子以及儿童的睡眠时间，建议每晚11个小时，不过，新生儿则建议每天睡眠可达18个小时。十几岁的青少年每晚应睡足10个小时。
Shane O'Mara, professor of experimental brain research at Trinity College Dublin, says that, while it's difficult to tell whether poor sleep is a cause or a symptom of poor health, these relationships feed off each other.
都柏林圣三一学院实验脑科学研究教授谢恩·奥玛拉介绍说，尽管很难说睡眠质量较差会是导致健康问题的原因或是健康问题的一个症状，但它们之间，确实具有互相促进的作用。
For example, people who are less fit exercise less, which leads people to sleep badly, become exhausted and less likely to exercise, and so on.
例如，健康水平较差的人，锻炼会少，这就导致睡眠不好，变得乏力，然后就更不大可能去锻炼，这样形成一个恶性循环。
We do know that chronic sleep deprivation - that is, under-sleeping by an hour or two a night over a period of time - has been linked time and again by scientists to poor health outcomes: you don't have to go for days without sleep to suffer these negative effects.
我们现在已经确实知道，长期习惯性的缺乏睡眠，即一段时期内每晚睡眠不足一个或两个小时，最终会导致健康问题，这已由科学家们多次研究证实，甚至，用不着连着几天不睡觉，就可以导致这些健康问题。
2. What happens in your body when you don't sleep enough?
2. 睡眠不足时身体会有什么反应？
Poor sleep has been linked to a whole range of disorders.
睡眠质量差，与系列紊乱失调，有着很大关系。
A review of 153 studies with a total of more than five million participants found short sleep was significantly associated with diabetes, high blood pressure, cardiovascular disease, coronary heart disease and obesity.
涉及超过500万研究对象的153项研究显示，睡眠不足与糖尿病、高血压、心血管疾病、冠心病以及肥胖症等都有很大关系。
Studies have shown that depriving people of enough sleep for only a few nights in a row can be enough to put healthy adults into a pre-diabetic state. These moderate levels of sleep deprivation damaged their bodies' ability to control blood glucose levels.
相关研究显示，只需连续几夜睡眠不足，即可让健康的成年人具有糖尿病前症状，这种中度的睡眠不足，会有损于身体控制血糖水平的能力。
Vaccines are less effective when we are sleep deprived, and sleep deprivation suppresses our immune system making us more prone to infection.
睡眠不足时，打疫苗的效果也会变差。睡眠不足也会损害身体的免疫系统，并进而更易被感染。
One study found participants who had fewer than seven hours of sleep were almost three times more likely to develop a cold than those who slept for seven hours or more.
有项研究显示，研究对象中，与睡够7个小时或更长的人相比，睡眠不足7个小时的人，患上感冒的可能性要高三倍。
People who don't sleep enough also appear to produce too much of the hormone ghrelin, associated with feeling hungry, and not enough of the hormone leptin, associated with feeling full, which may contribute to their risk of obesity.
睡眠不足的人也会分泌更多饥饿素荷尔蒙，会让人感到饥饿，与此同时，能让人具有饱感的消脂素荷尔蒙则分泌不足，这就可能增加肥胖的风险。
There are also links to brain function and even in the long term to dementia.
而且，睡眠不足也会影响大脑功能的正常运转，甚至长期来看，也会导致痴呆
Prof O'Mara explains that toxic debris builds up in your brain during the course of the day and waste is drained from the body during sleep. If you don't sleep enough, you end up in a mildly concussed state, he says.
奥玛拉教授解释说，白天时，大脑里会产生有害物质，晚上睡觉时，废物会排出体外。若是你睡眠不足，结果就会让你处于一种中度脑震荡状态。
The impact of sleeping too much is less understood, but we do know it is linked to poorer health including a higher risk of cognitive decline in older adults.
目前，人们对睡眠过度的影响，了解还比较少，不过，我们也已经确实知道，睡眠过度也与健康问题有关，如睡眠过度会提高年纪较大的成年人认知能力下降的风险。
3. We need different types of sleep to repair ourselves
3. 我们需要不同类型的睡眠来修复我们自身
After we fall asleep we go through cycles of "sleep stages", each cycle lasting between 60 and 100 minutes. Each stage plays a different role in the many processes that happen in our body during sleep.
入睡之后，我们会在不同的“睡眠阶段”之间进行循环，每次循环持续约60至100分钟。不同的睡眠阶段，对我们处于睡眠状态中的身体所发生的很多过程，有着不同的作用和影响。
The first stage in each cycle is a drowsy, relaxed state between being awake and sleeping - breathing slows, muscles relax, the heart rate drops.
每次循环的第一个阶段中，会感到昏昏欲睡，比较放松，处在清醒与熟睡之间的某种状态，呼吸变慢，肌肉放松，心率降低。
The second stage is a slightly deeper sleep - you may feel awake and this means that, on many nights, you may be asleep and not know it.
第二个阶段中，睡眠会稍微更深些，你可能会感到是醒着的，这也意味着，很多个夜里，你可能已经睡着，也不知道。
Stage three is deep sleep. It is very hard to wake up during this period because it is when there is the lowest amount of activity in your body.
第三个阶段中，是深度睡眠，在这个阶段，较难醒来，因为这时你身体内的活动水平是最低的。
Stages two and three together are known as slow wave sleep which is usually dreamless.
第二和第三个阶段一起被称为“慢波睡眠”，这时通常不会做梦。
After deep sleep we go back to stage two for a few minutes, and then enter dream sleep, also called REM (rapid eye movement). As the name suggests, this is when dreaming happens.
深度睡眠之后，我们会回到第二个阶段，持续几分钟，然后再进入“梦睡”，也被称作“快速眼动”阶段。正如名称所示，这时人们会做梦。
In a 39 38931 39 15288 0 0 3201 0 0:00:12 0:00:04 0:00:08 3201full sleep cycle a person goes through all the stages of sleep from one to three, then back down to two briefly, before entering REM sleep.
在一个完整的睡眠循环中，人们会经过从第一阶段到第三阶段的所有睡眠阶段，然后会回到第二个阶段持续几分钟，再然后进入“快速眼动”阶段。
Later cycles have longer periods of REM, so cutting sleep short has a disproportionately large effect on REM.
较晚的睡眠循环，“快速眼动”阶段会变长，因此，减少睡眠时长的话，就会给“快速眼动”阶段带来更大的影响。
4. Shift workers who have disturbed sleep get sick more often
4. 倒班工作的人因睡眠被扰乱更易患病
Shift work has been associated with a host of health problems. Researchers have found shift workers who get too little sleep at the wrong time of day may be increasing their risk of diabetes and obesity.
倒班工作与很多健康问题有关联。研究人员已发现，倒班工作的人因在不该睡觉的时间睡，因而睡眠会很不足，这也可能增加他们患上糖尿病和肥胖症的风险。
Shift workers are significantly more likely to report "fair or bad" general health according to a 2013 NHS study, which also found people in this group were a lot more likely to have a "limiting longstanding illness" than those who don't work shifts.
根据2013年英国国家医疗服务署的一项研究，倒班工作的人表示总体健康睡眠“一般或较差”的可能性会很高，该研究也发现，这些群体中的人，与不倒班工作的人相比，更易患上某种“特定的长期性疾病”。
People who work shifts are significantly more likely to take time off sick, according to figures from the Office for National Statistics.
英国国家统计局数据显示，倒班工作的人请病假的可能性也更高。
There is a far bigger gap for non-manual workers than manual workers - lack of sleep seems to have a bigger impact on those doing more sedentary jobs.
体力劳动者与非体力劳动者之间，这方面的差别更大，由此看来，睡眠缺乏会对久坐不动的工作者带来更大影响。
5. And many of us are feeling more sleep deprived than ever
5. 很多人感到比以前睡眠不足更严重
To judge from media reports, you'd think we were in the grip of a sleeplessness epidemic. But are we really all more sleep deprived than before?
媒体报道给人们的观感，会让人觉得，我们都患上了“无眠流行病”，不过，我们所有人，真的比以前更缺少睡眠么？
A big piece of research looking at data from 15 countries found a very mixed picture. Six showed decreased sleep duration, seven increased sleep duration and two countries had mixed results.
一组针对15个国家的研究数据显示，现实情况没那么简单，还挺复杂。其中，有6个国家的数据显示，睡眠时长有所降低，有7个国家的睡眠时长有所升高，有2个国家中，有升有降。
Lots of evidence suggests the amount we sleep hasn't changed that much in recent generations.
很多证据表明，近几代人中，我们的睡眠时长的变化并没那么大。
But if you ask people how sleep deprived they think they are, a different picture emerges.
不过，如果你问人们，他们觉得自己的睡眠缺乏会有多严重的话，情况则会有所不同。
So why do so many people report feeling tired?
因此，为什么会有这么多人表示感到困乏呢？
It may be that this problem is concentrated in certain groups, making the trend harder to pick up on a population-wide level.
有可能，这个问题只是集中于某些特定的群体，这就难以从人口整体的层面对那样的趋势进行验证。
Sleep problems vary considerably by age and gender, according to one study of 2,000 British adults. It found women at almost every age have more difficulty getting enough sleep than men.
根据一项针对2000位英国成年人的研究，睡眠问题会因年龄、性别等因素有很大不同。该研究发现，几乎在各个年龄阶段，与男性相比，女性都更难获得充分的睡眠。
The sexes are more or less level at adolescence but women begin to feel significantly more sleep deprived than men during the years where they may have young children, while work may become more demanding. The gap then shrinks again later in life.
在青春期阶段，男性和女性差不多持平，不过，当有了孩子后，女性就开始明显比男性感到缺乏睡眠，而工作因素，会加重这种问题。年龄再大点后，男性女性之间的这种差别会再缩小。
Caffeine and alcohol both affect sleep duration and quality.
咖啡因和酒精，都会影响睡眠的时长和质量。
And later nights and more social activities mean some of us are getting less rest, despite having the same number of hours of sleep, according to Prof Derk-Jan Dijk, of the University of Surrey's sleep research centre.
据萨里大学睡眠研究中心德克·让·戴克教授介绍说，熬夜、社交活动都会减少我们的休息时间，即使睡眠的小时数不变。
Some people may also sleep too little during the week and catch up at the weekend, bringing the average up but leaving those people feeling sleep deprived.
有些人可能在工作日睡眠较少，然后会周末补觉，把平均睡眠时间提上来，但即使这样，这些人也会感到缺乏睡眠。
For example, adolescents are particularly at risk of becoming sleep deprived, according to Prof Dijk.
戴克教授介绍说，比如，青少年缺乏睡眠的可能性会特别高。
6. But we didn't necessarily always sleep this way
6. 以前我们睡觉并不像现在这样
Aside from a few outliers - Margaret Thatcher could apparently get by on only four hours a night - people tend to go to bed in the late evening for around seven or eight hours.
除了极少数人，比如撒切尔夫人每晚只睡4个小时也完全没问题，而大多数人都会很晚才上床睡觉，睡上七八个小时。
But this wasn't necessarily always the norm according to Roger Ekirch, a history professor at Virginia Tech in the USA. He published a paper in 2001 drawn from 16 years of research.
不过，据美国弗吉尼亚理工学院历史教授罗杰·艾克奇介绍说，以前，人们并不总是这样睡觉。艾克奇教授曾基于16年的研究在2001年发表过一篇相关论文。
His subsequent book, At Day's Close, contained a wealth of historical evidence suggesting that hundreds of years ago, humans in many parts of the world slept in two distinct chunks.
艾克奇教授随后出版的《当白天结束》一书中，有大量的历史资料证据显示，几百年前，世界上很多地方的人们，都会分两次不同的时间段进行睡觉。
Dr Ekirch uncovered more than 2,000 pieces of evidence in diaries, court records and literature which suggest people used to have a first sleep beginning shortly after dusk, followed by a waking period of a couple of hours, then a second sleep.
艾克奇教授通过对2000多件日记、法院记录以及文学作品等资料的研究发现，人们会在黄昏来临后马上睡一觉，随后会醒来几个小时，然后在进行第二次睡觉。
He thinks this means the body has a natural preference for segmented sleep.
艾克奇教授认为，这就意味着，我们的身体有着一种自然的倾向性，倾向于阶段性睡眠。
Not all scientists agree. Other researchers have found hunter-gatherer communities in the modern world who sleep in one block despite not having electric lighting. This suggests sleeping in two blocks is not necessarily our default.
不过，不是所有的科学家们都同意这个观点。其他研究人员发现，现代社会中的狩猎采集群体也都是一次睡够，尽管他们也没用电灯照明。这就意味着，两阶段睡眠并不是人类固有的现象。
According to Dr Ekirch the shift from biphasal to monophasal sleep happened in the 19th Century because domestic lighting pushed bedtimes later with no corresponding change in rising time, improved lighting changed the human body clock, and the industrial revolution put a greater emphasis on productivity and efficiency.
据艾克奇教授介绍，从两阶段睡眠到一阶段睡眠的转变，发生在19世纪，因为家庭采用照明让睡觉时间变得更晚了，而起床时间却没有相应变化，照明状况的发展改变了人体的生物钟，而且，工业革命也更强调生产力水平和工作效率。
7. Phones are keeping teenagers awake
7. 手机正剥夺青少年的睡眠
Sleep experts say teenagers need up to 10 hours sleep a night, but almost half don't get this much according to the NHS.
根据英国国民健康服务署消息，睡眠领域的专家表示，青少年每晚的睡眠时间需要达10个小时，不过，几乎一半的青少年睡眠都不够这么长。
Bedrooms are supposed to be a place of rest but are increasingly filled with distractions like laptops and mobile phones, making it harder for young people to nod off.
卧室应该是休息的地方，但现在却有越来越多的诸如电脑、手机等分散注意力的东西，这就让青少年们更难以入睡。
We have more different types of entertainment on offer than ever, making the temptation to stay awake greater. The blue light emitted by electronic devices makes us feel less sleepy. And the activity itself - be it talking to friends or watching TV - stimulates our brain when it should be winding down.
目前，娱乐类型多种多样，前所未有，更具引诱力让人保持清醒。电子设备散发出来的蓝光，也会让我们睡意降低。而且，各种活动行为本身，不管是和朋友聊天还是看电视，都会在本应休息的时候给我们的大脑带来刺激。
Digital Awareness UK and the Headmasters and Headmistresses Conference recommend a nightly "digital detox", putting mobile devices away for 90 minutes before lights out.
“英国数字警觉”与“校长大会”倡议进行夜晚“数字戒瘾”，在熄灯前90分钟把移动设备放一边。
Last year the two organisations commissioned a poll which found a high proportion of young people check their phones after going to bed.
去年，这两个组织进行的一项调查发现，年轻人中，上床后查看手机的人占比处在高位。
8. Testing for sleep disorders is on the up
8. 睡眠紊乱就诊人数在上升
More people are turning up at their doctors complaining of problems sleeping.
现在，越来越多人人去看医生，诉苦说睡眠有问题。
Analysing data collected by NHS England, the BBC found in June that the number of sleeping disorder tests had increased every year over the past decade.
今年六月，我们通过分析英国国家健康服务署的统计数据发现，过去的十年间，睡眠紊乱就诊人数每年都在上升。
There are a number of factors, but the biggest is probably the rise in obesity, according to Dr Guy Leschziner, a consultant neurologist at Guy's and St Thomas' Hospital's Sleep Disorders Centre.
据盖伊圣托马斯医院睡眠紊乱中心的神经医学咨询医师盖伊·勒斯克资纳介绍说，有多种因素导致这些人数的上升，不过，最主要的因素可能是肥胖人数的上升。
The most common and fastest-growing complaint he sees is obstructive sleep apnoea - where the airway collapses and people stop breathing in their sleep - and this is strongly related to weight.
据盖伊所接触的病例中，最常见同时也是增长最快的一个问题是睡眠中呼吸暂停，即睡眠中气管不通，呼吸停止，这与体重有很大关系。
The media has also played a role because people are more likely to go to their GPs having read an article or searched for their symptoms online, he says.
据盖伊介绍说，媒体也起了一定的作用，主要是因为，人们看到相关报道后或网上搜索他们的症状后，可能就会去看医生。
The recommended treatment for insomnia is cognitive behavioural therapy, and doctors are increasingly aware that they shouldn't be prescribing sleeping pills. But many still do because it's difficult to access non-drug based treatments, particularly outside big cities.
治疗失眠的话，建议采用认知性行为治疗方法，而且，医生们越来越认识到，他们不应该开失眠药方，不过，很多医生还是会开药，主要是因为，不开药治疗失眠的办法还不太普及，特别是在小地方。
9. Are other countries doing it differently?
9. 英国是这样，其他国家情况如何呢？
One study looked at sleep habits in 20 industrialised countries.
有项针对20个发达国家睡眠习惯的研究。
It found variations of up to an hour in the time people went to bed and woke up, but overall sleep duration was fairly constant across countries. Generally, if a population on average went to bed later, they woke up later too, although not in every case.
该研究发现，人们上床睡觉的时间和睡醒的时间，相差可达1个小时，不过，总体的睡眠时长在不同国家却大致相当。总体来说，若人口中平均上床睡觉时间较晚，睡醒的时间也会相应较晚，不过情况也不总是会这样。
Researchers have concluded that social influences - hours worked, timing of school, leisure habits - play a far bigger role than the natural cycle of light and dark.
研究人员的结论就是，社会因素的影响，包括工作时长、上学时间、休闲癖好等所具有的影响，要比白天黑夜循环等自然因素所具有的因素要大很多。
In Norway, where the period of lightness each day varies through the year from zero to 24 hours, sleep duration throughout the year only varies on average by about half an hour.
比如，在挪威，随着一年四季的轮换，每天的光照时间可从0到24小时，而该国人口一年四季的睡眠时长差别平均只有半个小时。
Both in countries like the UK, where dusk and dawn times vary considerably across the seasons, and in countries closer to the Equator where dusk and dawn times vary minimally, sleep duration remains constant through the year.
在诸如英国等国，随着季节的变幻，白天黑夜时长会变化很大，而在接近赤道的国家，白天黑夜时长变化就非常小，而在这两类国家中，人们的睡眠时长一年四季却都大致一样。
But what about the impact of artificial light?
不过，源自人工照明的影响的作用会如何呢？
A study of three communities who had no access to electricity, in Tanzania, Namibia and Bolivia, found the average sleep duration was 7.7 hours - in step with industrialised countries.
针对分别位于坦桑尼亚、纳米比亚和玻利维亚三个国家的三个没有通电的社区的研究显示，那里人们的平均睡眠时长为7.7个小时，与发达国家大致相当。
So sleep duration seems remarkably consistent throughout the world - it's the time we all go to bed and wake up that varies slightly.
这样看来，睡眠时长在全世界范围内都相当一致，只是我们上床睡觉的时间和睡醒的时间稍有区别。
These pre-industrialised communities did not fall asleep as soon as it got dark, but around three hours after sunset and generally woke before sunrise.
那些没有通电的社区居民，并不会天一黑就马上睡觉，而会在日落三个小时左右后睡觉，一般在日出前睡醒。
Most studies in this area suggest that artificial light delays sleep time but does not necessarily decrease overall sleep duration.
该领域的很多研究都显示，人工照明会延缓入睡时间，不过总体上并不一定会导致睡眠时长缩短。
10. Morning larks, night owls?
10. 你是早起鸟还是夜猫子？
There have always been morning people and evening people. We even have genetic evidence that backs this up.
现实生活中，总会有些人会早起，有些人会晚睡，关于这方面，我们甚至已经有相应的基因证据来佐证这些现象。
But the introduction of artificial light appears to have exacerbated this effect, particularly for people who prefer to stay up late.
不过，人工照明的使用，貌似已让这种现象更为显而易见，特别是对于那些倾向于晚睡的人们。
If you are already inclined towards being a night owl, artificial light will make you stay up even later.
若你已经倾向于夜猫子型，那么人工照明的使用，会让你更晚睡。
About 30% of us tend towards being morning people and 30% towards being evening people, with the other 40% of us somewhere in the middle - although marginally more people prefer early rising to late nights.
约有30%的人会倾向于早期，有30%的人会倾向于晚睡，另外40%的人处于两者之间，尽管总体来讲，早期的人要比晚睡的人稍微多那么一点点。
We do have some control over our body clocks, however. Those who are naturally late to bed and late to rise can try reducing their exposure to light in the evenings and making sure they get more light exposure in the daytime.
不过，我们也确实能够对我们的生物钟施加一定的影响。倾向于晚睡晚起的人，可在夜晚减少光照时间，并在白天确保能有更多光照。
A team of researchers took a group of volunteers camping in Colorado, where they had no access to artificial light. Only 48 hours was enough to shift the campers' body clocks forward by almost two hours.
一个研究团队把志愿参加研究的一群人聚在科罗拉多州的一个地方，在聚居营地不使用人工照明，只需48小时就能让志愿者们的生物钟往前提约两个小时。
Levels of melatonin, the hormone that tells our body to prepare for sleep, began rising earlier in the volunteers - their bodies were preparing for sleep much closer to sunset.
志愿者身体中那种会告诉身体准备入睡的名叫“褪黑激素”的荷尔蒙的水平开始上升的时间会提前，这样，志愿者的身体准备入睡的时间就会距离日落时间更近。
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