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没有人造光的生活,我学到了什么

更新时间:2018-5-5 15:48:27 来源:千亿千亿国际娱乐官网 作者:佚名

What I learned by living without artificial light
没有人造光的生活,我学到了什么

We spend a third of our lives either sleeping… or trying to get to sleep. But in the world of 24/7 living and artificial light, our sleep is increasingly under threat.

人生有三分之一的时间,要么在睡觉,要么努力想睡着。不过在日日夜夜、每时每刻都有人造光的世界里,我们的睡眠面临的各种问题愈来愈多。

Many of us don’t get the recommended seven to nine hours we need each night and struggle to get up in the mornings – especially on work days. But it isn’t only our quantity of sleep that’s affected. Since the discovery that light (particularly blue light, emanating from devices like smartphones) can affect our biological clocks, evidence has been building that exposure to even low levels of light in the evening or at the night is disrupting our sleep quality, as well.

专家建议人们每晚要睡足七到九个小时。很多人睡眠不足,第二天起床也有困难,在工作日尤甚。不过重要的并非只有睡眠时长。研究发现光线会影响人们的生物钟,尤其是手机之类的设备发出的蓝光。越来越多的证据表明,即使晚上或者深夜里不强的光线,也会使我们的睡眠质量受到影响。

So what would happen if we turned off the lights? Would it improve our sleep or have other benefits? And how easy would this be to achieve in a modern city?

如果把灯关了会怎么样呢,睡眠质量会提高吗?还是会有别的好处?在现代城市中,这一切容易实现吗?

One recent winter, I decided to find out. Working with sleep researchers Derk-Jan Dijk and Nayantara Santhi at the University of Surrey, I designed a programme to go cold-turkey on artificial light after dark, and to try to maximise exposure to natural light during the day – all while juggling an office job and busy family life in urban Bristol.

上一个冬天,我决定去找寻答案。我和英国萨里大学的睡眠研究人员迪克(Derk-Jan Dijk)、桑提(Nayantara Santhi)合作,设计了一个天黑后彻底戒除人造光的项目,还试着在白天尽量处于自然光中。做这一切的同时我还得处理好自己在英国布里斯托尔市区一个办公室的工作,还有繁忙的家庭生活。

The discoveries I've made have revolutionised my attitude to light ­­­– and how I live my life during the night and day. I now make simple, daily choices that can transform how I sleep, how I feel and perhaps even my cognitive abilities. Could you be doing the same?

此后的发现彻底改变了我对光线的态度,还有白天夜晚的生活方式。现在我这种简简单单的日常选择能改变自己的睡眠方式、感觉,甚至还有我的认知能力。你能做到吗?

For millennia, humans lived in synchrony with the natural cycle of light and dark. This doesn’t mean that everyone went to sleep as soon as the Sun set. Studies of pre-industrial societies, such as tribes living in Tanzania or Bolivia today, suggest that people stay up for several hours after dark, often socialising by firelight. In fact, the amount of sleep they get is quite like people in industrialised countries, but the timing is more in line with the natural cycle of day and night: they tend to go to bed earlier and get up just before dawn.

几千年来,人们日出而作、日落而息。但并非天一黑,所有人都去睡觉。若研究前工业社会,比如今天生活在坦桑尼亚和玻利维亚的部落,就能发现人们在日落后还会借着火光进行一些社交活动。事实上,他们和工业化国家的人们睡得差不多久,只不过更符合日升月落的自然循环,不仅睡得早,而且黎明前就起来了。

“In modern societies, at least on weekdays, we don’t sleep in tune with our body clock,” says Dijk. Exposure to artificial light at night is shifting our body clocks later. But we still need to go to work in the morning, so we set an alarm clock – even though the biological clock says we should still be asleep.

“现代社会中,我们不会按照生物钟的点儿去睡觉,至少工作日如此,”迪克说。夜晚依旧无处不在的人造光正让我们的生物钟越来越迟。但第二天一早大家还是得爬起来上班,所以要定个闹钟,否则按照生物钟我们应该接着睡觉。

Pre-industrial societies such as the Hadza tribe in Tanzania also seem to have a far lower prevalence of sleep problems, like insomnia. “When we asked members of the Hadza whether they thought their sleep was good, they almost universally said ‘yes, it’s totally fine’. That statistically doesn't match up with what we see in the West,” says David Samson, an anthropologist at the University of Toronto in Mississauga, who has studied them.

在前工业社会中,比如坦桑尼亚的哈扎族,失眠这类睡眠问题不太普遍。“问及哈扎族成员睡得如何,他们几乎都说'挺好,完全没问题”。这种数据和我们在发达国家看到的完全不一样。”加拿大多伦多大学密西沙加分校的人类学家萨姆森(David Samson)说。

Why is this? Light enables us to see, but it affects many other body systems as well. Light in the morning advances our internal clock, making us more lark-like, while light at night delays the clock, making us more owlish. Light also suppresses a hormone called melatonin, which signals to the rest of the body that it’s night-time – including the parts that regulate sleep. “Apart from vision, light has a powerful non-visual effect on our body and mind, something to remember when we stay indoors all day and have lights on late into the night,” says Santhi, who previously demonstrated that the evening light in our homes suppresses melatonin and delays the timing of our sleep.

这是为什么呢?光线让我们的双眼看清世界,但同时也影响了身体的其它器官。晨光提早了我们的生物钟,趋同早起的百灵鸟,而晚上的光线延迟了生物钟,趋同于熬夜的猫头鹰。光也抑制了褪黑激素。这种激素会给全身发信号,包括调节睡眠的器官,表示晚上到了。"除了视觉,光线对我们的身心都有强大的非视觉影响。还记得我们在室内待了一整天,开着灯熬到深夜么?"桑提说。此前她证实了家里的夜光灯会抑制褪黑激素,延迟我们睡觉的时间。

However, light also boosts alertness in its own right. It’s like drinking a double espresso. Although these stimulant effects are bad news if you’re trying to sleep, being exposed to more bright light during the daytime could make us more alert. Light also stimulates brain regions that regulate mood.

然而,光线本身就让我们提高了警觉性,就像喝了特浓咖啡。若是要睡觉,这种刺激性效果就十分恼人。不过要是在白天,处于亮光下倒是能让我们更为机警。光线也刺激了大脑中调节情绪的区域。"

“The important thing is that we create a light exposure pattern with sufficient light during the day, and not too much light in the evening,” says Dijk.

重要的是我们要创建了一个光线照射机制,白天光线充足,晚上没多少亮光。"迪克说。

Despite this logic, persuading my family to let me switch to this way of living took some effort. When I suggested to my husband that living by candlelight might be romantic, he rolled his eyes. But convincing him was a doddle compared to my six-year-old daughter and four-year-old son. Here’s how that conversation went:

除此之外,劝说家里人改成这种生活方式,倒是花了不少力气。我向丈夫提议晚上用蜡烛也许会很浪漫,他直接翻了白眼。不过相比于我6岁的女儿和4岁的儿子,说服我丈夫已经算是轻而易举了。以下是对话的过程:

Me: Children, we’re going to try living in the dark for a few weeks

我:孩子们,我们要在黑暗里生活几周。

Daughter: But that will be spooky.

女儿:但那会很怕怕。

Me: No, I think it could be lots of fun. We’ll have candles.

我:不会啊,会很有趣。我们有蜡烛的。

Daughter: (bursts into tears)

女儿:(开始大哭)

Me: Please don’t cry. It will be like going camping.

我:别哭呀。会像露营一样。

Son: Can we have marshmallows?

儿子:有棉花软糖吃吗?

Several packets of marshmallows later, we were set – although I agreed that my husband could occasionally use electric lighting and the kids could watch television, provided I wasn’t nearby. Because I needed to maintain a normal work schedule, I also decided to keep the lights on until 18:00, although I switched my laptop to ‘night mode’ after sunset.

应允了几包棉花糖,总算搞定了全家人,尽管我同意自己不在时,丈夫偶尔可以用电灯,孩子也可以看电视。因为我自己也得保持正常的工作进度,所以决定在18:00前都开着灯,日落后把笔记本电脑切换到“夜间模式”。

The protocol looked like this: during the first week, I would try to maximise my exposure to daylight by moving my desk next to the window, lingering in the park on the way back from school drop-off each morning, getting outside at lunchtime and trying to exercise outdoors. The second experimental week would be spent minimising my exposure to artificial light after 18:00, relying on candle-light or dim red lighting instead. Then I would combine the two.

计划大致如下:第一周,把书桌移到窗边,每天早晨送小孩上学后在路边公园里多待一会儿,午饭出去吃,到户外锻炼,总之尽可能多地接触日光。实验第二周,减少自己在18:00后接触的人造光,而是用烛光或者暗红色灯光。再之后就将前两周的做法结合。

In between each of these intervention weeks, I would lead a normal life. These weeks would function as a baseline.

除了这几周,其它时间我会像平时一样生活,以此作为基准。

To track my responses, I’d wear an ‘actiwatch’ to measure light exposure, activity and sleep. I'd also complete sleep diaries and questionnaires to assess my sleepiness and mood and undertake a battery of cognitive tests to assess my short-term memory, attention and reaction speeds. On the last evening of each week, I would spend the evening in darkness, taking hourly samples of my melatonin, which is released in response to a signal from the biological clock and therefore provides a marker of our internal time. “Melatonin is our hormone of darkness; it creates the biological night,” says Marijke Gordijn, a chronobiologist at the University of Groningen in the Netherlands, who measured my melatonin levels.

为了追踪自己的反应,我会戴上“活动记录仪”来测试光照、活动和睡眠。我也会完成睡眠日志和问卷来评估自己的睡眠和情绪,以及做一整套的认知测试来评估自己的短时记忆、注意力和反应速度。每周最后一晚,我会在黑暗中度过,每小时测试自己的褪黑激素。(为了回应生物钟信号,人体会释放褪黑激素,因而可以用来标记人体内部的生物钟。)“褪黑激素是我们在黑暗中会产生的激素,它创造的是生物钟时间里的夜晚。” 荷兰格罗宁根大学的时间生物学家高迪金(Marijke Gordijn)这么说,她为我测试褪黑激素水平。

The idea was to see if these changes to my light exposure altered the timing of my biological clock. We were curious to see if any of the benefits predicted by larger, well-controlled laboratory studies would translate into real life.

这个主意是为了测试我每天光照时间的变化是否会改变生物钟时间。我们很想知道,那些大型、精密实验室预测到的好处能否运用于现实生活。

“We’ve done a lot of experiments where we’ve given a dose of light and seen that it shifts the clock,” says Gordijn. “But if we want to apply those findings to help people, we need to know that it will have the same effect when the environment is more variable.”

“我们做了很多实验,给出一定的光照,看看会不会改变生物钟,”高迪金说,“但如果想用这些发现来帮助人们,还得知道环境更多变时,会不会有同样的效果。”

Switched on

实验开始

And so, on a bright and sunny December morning, I found myself in the local park, inconspicuously trying to work out on the monkey-bars and swings instead of going to a body pump session in the gym. "Mummy, what's that lady doing?" asked a small boy.

所以,在一个阳光明媚的12月清早,我在当地一个公园里,发现自己不知不觉已在健身云梯和秋千上晃来晃去,而非去健身房做杠铃操。一个小男孩问:“妈妈,那位女士在干嘛呢?”

Because it was winter and most people were inside keeping warm, the park was largely deserted. Motivation had been a struggle for me also. It’s hard to overcome the belief that because it’s winter, it will be cold and miserable outside. However, I was reminded of something a Swedish friend used to say: there’s no such thing as bad weather, only inappropriate clothing. And I soon realised that its rarely as bad outside as it may look. Indeed, the more I did it, the more I came to regard getting outdoors in winter as a treat, rather than a chore.

当时是冬天,大部分人都躲在室内取暖,公园几乎没什么人。我自己也是挣扎着才去的,毕竟是寒冬,很难克服一出门就又冷又痛苦的想法。不过我想起以前一位瑞典朋友的话:没有什么天气不好,只有穿得不对。并且我很快就发现外面不太会像看起来那么糟糕。事实上,出来的多了,就开始把冬天出门当成享受,而非折磨。

On another morning, I sat in the park with a cup of tea on my way back from dropping the kids at school and got out my light meter. The illuminance of light is measured in lux. On a cloudless day in summer, the light outdoors can reach as high as 100,000 lux; on an overcast day, it can be as low as 1,000 lux. Today, the reading was 73,000 lux.

另一天早上,把孩子送到学校后返回,我坐在公园里边喝茶,边拿出了照度计。光照度以勒克司为单位,夏天晴朗时,户外光线高达10万勒克司,阴天低至1000勒克司。而今天,读数是73000勒克司。

Back indoors, I took a reading in the centre of my shared office: 120 lux – lower even than the 500 lux you’d expect outdoors immediately after sunset. Horrified, I returned to my temporary desk by the window, where it was colder, but a sunnier 720 lux.

回到室内,我在公共办公室的中央测了读数:120勒克司,甚至比在户外刚刚日落后测到的500勒克司还低。我吓了一跳,回到自己靠窗的临时书桌旁,这里虽然冷,好歹阳光充足,有720勒克司。

Despite my best efforts to get more daylight during the intervention weeks, my average light exposure between 7:30 and 18:00 was 397 lux during the first week and just 180 lux during the second. This was presumably because I still spent most of the day indoors, working at my computer, and because the Sun set at around 16:00. The likely reason for this variation was the weather. During the first week, there were 4.5 hours of bright sunshine per day on average, whereas in the second week it was just 0.9 hours. This was still an improvement on baseline weeks, though, when my average daytime exposure was just 128 lux.

尽管在这两周里尽可能去接触了日光,我在7:30至18:00之间的平均光照为:第一周397勒克司,第二周仅180勒克司。这大概是因为我大部分时间仍然在室内用电脑工作,而且日落大约在16:00。这种变化很有可能是因为天气。第一周, 平均每天有4.5小时的明媚阳光,而第二周却只有 0.9小时。不过跟平均光照时间只有128勒克司的基准周比起来,还是有所提高的。

It wasn’t only the weather that proved challenging. For the first few nights of the experiment, we slept with the curtains open to maximise exposure to the dawn light. Light at this time is thought to shift the body clock earlier.

不仅仅只有天气会带来挑战。实验刚开始的几晚,我们睡觉时拉开了窗帘,尽可能感受第二天的晨曦。清早的光线据说能让生物钟变早。

But at night-time, the light from the streetlights made it difficult to sleep.

但是在夜里,路灯的光就使人难以入眠。

I’m not alone in experiencing this problem. In 2016, researchers reported that people living in urban areas of more than 500,000 people are exposed to night-time light levels that are three to six times brighter than people in small towns and rural areas. Those living in areas of more intense light sleep less, are more tired during the daytime, and report feeling more dissatisfied with their sleep. They also go to bed and wake up later than people in darker areas.

我不是唯一遇到这个问题的人。2016年,研究人员报告说,超过50万的城市居民遭受的夜间光照度,比小城镇和乡村居民高3到6倍。灯光越强烈的地方,人们睡得越少,白天越容易疲劳,而且据报道,这些人对自己的睡眠更为不满。他们上床睡觉和起床都比灯少较暗的地方要晚。

After a few days of this, I began closing the curtains and using a dawn simulation clock instead. It was an imperfect solution, as the light from these devices isn’t as bright as daylight. But it was better than nothing.

几天后,我开始拉上窗帘睡觉,取而代之用了个模拟黎明亮光的闹钟。这个方案也有缺陷,设备发出的光线没有日光那么亮。不过也聊胜于无。

If exposing myself to more daylight wasn’t hard enough, I also had to eliminate evening light during December, the darkest month of the year. Doing so brought home to me just how useful artificial light is. Cooking by candle-light was a daily challenge, chopping vegetables an outright hazard. I began to prepare meals earlier in the day, which ate into my work time and meant I got less done.

如果接触更多的日光还不算难事,那难的估计要数在最没太阳的12月不得不减少夜间灯光。这让我感受到家里的人造光有多重要。在烛光下烹饪还算日常挑战,烛光下切菜彻底成了危险。我开始在白天早早准备饭菜,这占用了工作时间,害的我进度减慢。

Eventually, I employed another work-around. I installed some smart lightbulbs in my kitchen, that could be dimmed and colour-adjusted using an app on my smartphone. This, of course, created a paradox: to remove the alerting blue light from the bulbs, I had to expose myself to blue light from my phone, so I did it in the daytime to avoid invalidating the experiment. Now our kitchen glowed an eerie red-orange by night. But at least we could cook again.

最后我采用了另一个解决方案,在厨房装了些智能灯泡,可以用手机软件调暗调色。不过这又导致自相矛盾:为了远离灯泡里那种提神的蓝光,我就得接触手机的蓝光屏幕,所以我在白天把光调好,免得影响了实验。现在我们家厨房里晚上的灯光是诡异的橘红色,不过好歹又能烧饭了。

During my ‘dark weeks’, I was exposed to an average illuminance of 0.5 lux between 18:00 and midnight and a maximum of 59 lux. That was compared to an average 26 lux (and a maximum of 9640 lux – I have no idea what this super-bright, artificial light source was) when I lived normally – although the actiwatch on my wrist wouldn’t have detected any light emitting from my smartphone or laptop during baseline weeks. That’s important, because there’s mounting evidence to suggest that these devices can disrupt sleep.

在“黑暗周”中,我在每天18:00到凌晨之间接触的光照度均值是0.5勒克司,峰值是59勒克司。相比之下,正常生活时均值是26勒克司,峰值是9640勒克司,也不知道这个超级亮的人造光源是什么。不过在基准周,我手腕上的"活动记录仪"也没探测到手机和笔记本电脑发出的光。这个发现还是很重要的,因为有越来越多的证据表明这些设备会干扰睡眠。

One 2015 study suggested that using an e-reader before bed prolonged the amount of time it took for people to fall asleep, delayed the circadian clock, suppressed REM sleep, and left participants feeling more tired the next morning, compared to people who read a print book for the same amount of time.

2015年的一项研究发现,睡前使用电子阅读器会延长人们入睡的时间,延迟生物钟,并且抑制深睡眠。跟睡前用同样的时间阅读纸质书的参与者相比,使用电子书的参与者第二天会更疲劳。

Another recent study compared people’s responses when they played computer games during the evening on a normal smartphone screen versus one that suppressed blue light. Players felt more alert after using the conventional smartphones and performed worse in cognitive tests the next day, suggesting that their sleep may have suffered.

最近还有一个研究对比了两类人的反应:在晚上用普通智能手机玩游戏的人,和没接触到蓝光的人。使用传统智能手机玩游戏之后,人会更警觉,在第二天的认知测试中表现较差,说明他们的睡眠可能受到了影响。

My pledge to avoid artificial light also made socialising difficult. A few days before my experiment started, a friend invited us over to her house for pre-Christmas drinks in the middle of a “dark week”. When I explained my predicament, she generously offered to let me sit upstairs in a candle-lit room and receive visitors. I politely declined, feeling how I imagine vegans must feel when they’re invited out to a meal at a steakhouse.

为了恪守避免人造光的承诺,我也经历了社交难题。实验开始前几天,一位朋友邀请我们在圣诞节前去她家小聚,聚会时间刚好就在“黑暗周”中。我向她解释了自己的窘境,她很慷慨地让我去她家楼上一间有烛光的房间里坐一坐,在那和朋友聚会。我礼貌地谢绝了,感受到了素食主义者受邀去吃牛排时的感受。

Instead, we encouraged friends to come to our house, and so they came: amused, curious, and occasionally concerned about what they might find. One family initially declined our invitation to stay for New Year because they were worried their son might knock over the candles. They changed their mind when I told them they could use the lights in their bedroom. (We kept all candles out of kids’ reach, just in case.)

相反,我们还鼓励朋友来家做客,大家带着愉悦和好奇来了,偶尔还关心一下在我家会发现什么。有一家子一开始婉拒了我们请他们来过年的邀请,怕儿子会打翻蜡烛。不过当我告诉他们可以在自己的房间里开灯,他们又愿意来了。(我们把所有蜡烛都放在孩子够不到的地方,以防万一。)

Once we’d adapted to the challenges, living without artificial light was very pleasant. Conversation seemed to flow more easily, and visitors also commented on how mellow and relaxed they felt in the dim light. Another bonus was that our children seemed to settle down more easily in the evenings, although we didn’t collect any data on this.

一旦适应了这些困难,没有人造光的生活就变得很愉快。那种环境似乎更利于展开对话,客人也表示在昏暗的烛光中,内心更为平和、放松。还有一个好处是,孩子们似乎更容易安静下来,但我们没有收集过相关数据。

But did any of this make any difference to my sleep or mental performance? There was a general trend towards earlier bedtimes during the intervention weeks – particularly during the week when increased daylight was combined with low evening light. On this week, my average bedtime was 23:00, compared to 23:35 on baseline weeks.

不过,这些对我的睡眠和精神状况有什么影响呢?在干预周里,尤其是在同时增加日光接触和减少夜晚人造光的那一周里,就寝时间有大体上变早的趋势。在这一周,我的平均就寝时间是23:00,而在基准周,是23:35。

As it was December, I had a lot of social commitments, so I occasionally ignored my body’s sleep signals and stayed up later. It’s an issue that researchers often encounter in their studies. “People have social obligations, and it’s very hard for them to follow what their clock is telling them to do,” says Mariana Figueiro, director of the Lighting Research Center in Troy, New York. “We are constantly fighting our physiology.”

到了12月,我参加了很多社交活动,所以偶尔会忽略身体困倦的信号,转而开始熬夜。这也是研究人员在研究中经常碰到的问题。美国纽约州特洛伊市照明研究中心(Lighting Research Center)的费古埃洛(Mariana Figueiro)说:“人们都有社会责任,很难按生物钟行事。我们一直在跟自己的生理机能作斗争。”

Even so, I was significantly sleepier in the evenings during the increased daylight and low evening light intervention weeks. My body also started releasing the darkness hormone, melatonin, some 1.5 hours earlier during the daylight intervention week – and two hours earlier when I avoided evening light.

即便如此,在同时增加日光接触和减少夜间人造光的干预周里,我明显觉得晚上特别困。在只增加日光接触的干预周里,我的身体释放黑夜荷尔蒙,即褪黑激素的时间早了1.5小时,在只避免夜间灯光的干预周里,则提早了2小时。

It is a pattern that’s been seen in other studies. Like me, Kenneth Wright at the University of Boulder in Colorado has long been fascinated by how our modern lighting environment might be affecting our internal timing. So in 2013, he sent eight people camping in the Rocky Mountains of Colorado for a week during the summer and measured how this affected their sleep. “Camping is an obvious way of removing ourselves from this modern lighting environment and just getting access to natural light,” says Wright.

其它研究也发现了这一规律。和我一样,美国科罗拉多州博尔德大学的莱特(Kenneth Wright)一直对现代照明环境如何影响生物钟很感兴趣。2013年,他在夏季派出八个人去美国科罗拉多州的落基山脉露营一周,以此来测试对睡眠的影响。“露营显然会远离现代照明环境,让人多接触自然光线。”莱特说。

Before the trip, the participants’ average bedtime was 00:30 and their wake time 8:00. Both had shifted approximately 1.2 hours earlier by the end of the trip. They also started releasing melatonin some two hours earlier once they were removed from artificial light – although they didn’t sleep for any longer.

此行之前,参与者的平均就寝时间是00:30,起床时间是8:00。行程结束时,这两个时间都提早了约1.2小时。虽然远离人造光线没有延长睡眠时间,却让褪黑激素的释放提早了约2小时。

Wright recently repeated the study in winter. This time, he found that participants went to sleep some 2.5 hours earlier under natural lighting conditions but woke up at roughly the same time as when they were living indoors. This meant they slept for around 2.3 hours longer. “We think it’s because people were going back to their tents earlier to get warm, so they were giving themselves a longer opportunity to sleep,” says Wright.

最近,莱特在冬季重复做了这项研究。这一次,他发现参与者们在自然光中提早了2.5小时就寝,但是醒来时间却和他们在室内生活时差不多。这说明他们多睡了2.3小时。“他们早早回到帐篷里取暖,给自己更长的时间进入睡眠,”莱特说。

Unlike his participants, I didn’t experience a sizeable increase in the amount of sleep I got during the intervention weeks – although there was a slight increase in sleep time and efficiency (the ratio of the total time you spend asleep versus the amount of time bed). However, this didn’t reach statistical significance, meaning it could have been the result of chance. Perhaps it was because I was living in a relatively warm house, which made defying my body clock easier. I also was forced to get up at the same time each morning by my children – who occasionally woke me at night, too.

与这些参与者不同,在干预周里,我的睡眠时间没有大幅延长。不过睡眠时间和效率还是有轻微的提升(可以通过入睡时间和就寝时间的比例看出来)。不过这个还没有达到统计学意义,可能只是种偶然。也许是因为我生活在相对温暖的室内,对抗生物钟更加容易。而且每天早上同一时间我都会被孩子们叫醒,偶尔夜里也会把我吵醒。

But when I correlated my sleep with the amount of light I was exposed to during the daytime, an interesting pattern emerged. On the brightest days, I went to bed earlier. And for every 100 lux increase in my average daylight exposure, I experienced an increase in sleep efficiency of almost 1% and got an extra 10 minutes of sleep.

不过当我将自己的睡眠和白天接触的光照量联系起来,就发现一个有趣的规律。阳光越灿烂,我睡得越早。我的平均光照量每增加100勒克司,睡眠效率就能提高近1%,睡眠时间也会延长10分钟。

I also felt more alert upon waking during all three intervention weeks – but particularly during the two weeks when I was exposed to more daylight.

在这三周干预期内,尤其是在增强了光照的那两周,我醒来后也会更警觉。

This pattern has been seen in other studies too. The General Services Administration is the largest landlord in the United States. Many of the public buildings it manages either were designed to try and boost indoor daylight levels or have been remodelled, so its leaders were keen to find out if this had made any difference to the health of those working inside them. Working with the Lighting Research Center’s Figueiro, they picked four such office buildings, plus the GSA Regional Office Building in Washington DC – a converted warehouse which had little access to natural daylight at that time. Workers were asked to wear a device that collected light data around their necks, as well as to complete daily mood and sleep questionnaires for a week during summer and again in winter.

也有别的研究发现了这个规律。总务管理局(General Services Administration)是美国最大的房东。它管理的许多公共建筑,要么在设计时就尽量提升了室内采光,要么就重新进行了采光改造。管理层对采光是否会影响楼内部工作人员的健康十分重视。他们与照明研究中心的费古埃洛合作,选择了四幢这样的办公大楼,外加总务管理局在华盛顿特区的区域办公大楼(那里的仓库经过改建,很难获得自然光)。他们要求职员在脖子上佩戴收集光照数据的设备,还要在冬夏两季的某一周分别完成每日情绪和睡眠问卷。

When the light data started to come in, it was initially disheartening. Despite efforts to boost daylight in the workplace, many GSA workers weren’t receiving it. “Our study revealed that if you are three, four, five feet from the window, you lose the daylight,” Figueiro says. “It’s not just your distance from the window that matters. You have partitions, people pulling the shades. Having a window doesn’t necessarily mean you’re going to get good daylight.”

光照数据收集起来,一开始令人十分沮丧。尽管已经尽量在工作场所提高采光,很多总务管理局的职员仍然接收不到光照。费古埃洛说:“我们的研究反映,如果你离窗户有一到一米半远,就照不到日光了。关键不仅在于你离窗户有多远,还有隔板产生的阴影。办公桌前有一个窗户并非就等于可以接收到足够的采光。”

Probing further, Figueiro’s team divided the office workers into those who were receiving a high circadian stimulus – light that was bright or blue enough to activate the circadian system – and those who were receiving a low stimulus.

为了进一步探究,费古埃洛的团队将办公大楼里的职员分成两类:一群人接收生物钟高刺激强光——就是那种能激活生理系统的极亮或者极蓝的光线,还有一群人接受低刺激弱光。

Those who received a high stimulus took less time to fall asleep at night and slept for longer. Morning light seemed to be particularly powerful: those exposed to a high stimulus between 8:00 and 12:00 took an average 18 minutes to fall asleep at night, compared to 45 minutes in the low stimulus group. They slept for an extra 20 minutes. Their sleep efficiency was 2.8% higher. And they reported significantly fewer sleep disturbances. These associations were stronger during winter, when people may have had less opportunity to receive natural light during their journey to work.

接触高刺激光线的人晚上睡着得更快、睡得更久。晨光似乎尤为有效,在 8:00到12:00之间接触弱光的人,平均入睡时间为45分钟,相比之下,强光组只要18分钟就能入睡,还能额外多睡20分钟,睡眠效率也高2.8%。而且据报告称,他们的睡眠问题明显较少。人们在冬天上班途中接收的日照可能较少,这些关联就更为明显。

Gordijn also recently published a study which found that people slept better following more exposure to daylight. Here, the participants were wired up to polysomnography monitors to record their sleep in detail. “People had more deep sleep, and it was less fragmented after more exposure to daylight,” Gordijn says.

高迪金最近也发表了一项研究发现,越长时间暴露在日光下,人睡得越好。参与者在研究中接了多导睡眠仪来记录睡眠细节。高迪金说:“日光照得越多,人们睡得越沉,碎片式睡眠也越少了。”

Light heart

放松心态

Until recently, scientists had assumed that our urge to sleep was driven by two independent systems: the circadian system, which affects sleep timing, and a ‘homeostatic system’ which keeps tabs on how long you’ve been awake and ratchets up the pressure to sleep.

近来,科学家们一直认为,令我们去睡觉的冲动由两个独立的系统驱动:影响睡眠时间的“生理昼夜系统”,还有监视我们醒了多久,逐步促使睡眠的“自我调节系统”。

Light was known to alter the timing of sleep via the circadian system. But recent work by Samer Hattar at the University of Maryland has suggested that the light-sensitive cells in the eye, which control the circadian system, also connect to the homeostatic system. “We propose that the timing and intensity of light exposure doesn’t only modulate circadian-driven aspects of sleep, but also homeostatic sleep pressure,” Gordijn says.

光线能通过生理昼夜系统改变睡眠时间,这一点已人尽皆知。不过美国马里兰大学的哈特(Samer Hattar)在近期研究表明,控制生理昼夜系统的眼部感光细胞也跟自我调节系统息息相关。“我们认为光照时间和强度不仅能改变生物钟驱动的睡眠,也会自我平衡睡眠压力,”高迪金说。

Daylight also affects mood. Those GSA office workers who were exposed to brighter morning light scored lower on a self-rated scale of depression. Other research has shown that morning light, as well as light during the day, can improve symptoms of non-seasonal depression.

日光还会影响情绪。总务管理局大楼里那些接触明媚晨光的职员,在自我评估抑郁时得分就很低。其它研究也表明,晨光和日光都能改善非季节性抑郁症的症状。

“It probably has to do with being more entrained to the light/dark cycle and sleeping better,” says Figueiro. In her study, those who recorded a high circadian stimulus in the daytime tended to be more active during daylight hours and less active once it got dark, suggesting their sleep was more aligned with their internal clock.

“这个也许和昼夜循环有关,也决定是否能睡得更好,”费古埃洛说。在她的研究记录中,那些白天接触了高生理刺激光线的人,天亮时会更活跃,天一黑就消停了,说明他们的睡眠和生物钟息息相关。

These data are in accordance with office studies in the UK. In March 2007, Dijk and his colleagues replaced the light bulbs on two floors of an office block in northern England, housing an electronic parts distribution company. Workers on one floor of the building were exposed to blue-enriched lighting for four weeks; those on the other floor were exposed to white light. Then the bulbs were switched, meaning both groups were ultimately exposed to both types of light. They found that exposure to the blue-enriched white light during daytime hours improved the workers’ subjective alertness, performance, and evening fatigue. They also reported better quality and longer sleep.

这些数据与英国的办公室研究十分一致。英格兰北部的一幢办公大楼里常驻着一家电子零件分销公司,2007年3月,迪克和他的同事换掉了两层楼的灯泡。在四个礼拜中,一层楼里的员工数被暴露在强蓝光下,另一层的员工则暴露在白光中。然后互换灯泡,使两组人最终都接受两组光照射。他们发现,白天照射了强蓝白光的员工有更强的主观警觉性和业务表现,夜晚的疲劳程度也增加了了。他们还说自己睡得更好、更久。

This also fits with my own findings. Immediately after waking and before going to bed each night, I filled out a questionnaire to assess how positive and negative I was feeling. The results suggest that my early-morning mood was significantly more positive during the intervention weeks compared to when I was living normally. There was also a trend towards less negative feelings in the evening.

这也符合我自己的发现。每天醒来后、睡觉前,我都会及时填写问卷来评估情绪。结果显示,相比通常的生活来说,我早上的情绪在干预周里明显更积极,晚上也没那么消极。

And although I didn’t officially assess my mood at any other time of day, I felt more energetic and uplifted on those weeks when I spent more time outside. Because of my experience, I’m a convert to outdoor exercise. I’m also learning to embrace the long winter nights: seeing the season as an opportunity to make the house cosy with candles rather than bemoaning the darkness.

虽然我没有正式评估一天中其他时间的情绪,但在我花了更多时间在户外的那几周,感觉精力充沛,而且精神振奋。这个经历让我成了户外运动爱好者。我也学着享受漫长的冬日夜晚,在这个季节用蜡烛装点温馨的家不正是大好时机嘛,何必抱怨屋子太黑暗呢。

Even my daughter is a convert. Towards the end of the experiment, I asked her if she was looking forward to switching the lights back on. "No," she said. "It has been wonderful, because the candles are really relaxing." Instead, it was my four-year-old son who insisted: he wanted to see what he was eating at dinnertime.

甚至连我的女儿都变了。实验到最后,我问她期不期待重新开灯。她说:“不期待,现在这样挺好,点着蜡烛很放松。”不过我四岁的儿子却还是老样子,他想开灯看清楚晚饭吃了什么。

Although none of my cognitive test results achieved statistical significance, there was a trend towards faster reaction speeds during the intervention weeks, as well as slightly better performance in a test that involved remembering where a token was hidden in a series of boxes.

虽然我的认知测试结果没有一项具有统计学意义,不过在干预周里,我的反应速度更快。而且当测试记忆一个记硬币藏在哪个盒子里时,表现会稍好些。
 
Studies by Gilles Vanderwalle at the University of Liège in Belgium and Dijk have shown that exposure to bright light activates brain areas involved in alertness – although in these studies, the effects weren’t long-lasting.

迪克和比利时列日大学的范德瓦尔(Gilles Vanderwalle)所作的研究表明,接触亮光能激活大脑中的警觉区。不过在研究中,接触亮光带来的效果并不长久。

However, in a separate study, researchers at Charité Universitätsmedizin in Berlin discovered that the energising effects of light continued for the rest of the day. When participants were exposed to bright, blue-enriched light in the morning, they reported feeling less sleepy during the evenings, and their reaction speeds were maintained, rather than declining as time wore on. Also, the bright morning light seemed to buffer their body clocks against the effects of blue evening light – a finding which is in accordance with current mathematical models of how light affects the human biological clock and sleep.

不过在另一项研究中,德国柏林夏瑞蒂(Charité)医科大学的研究人员发现,光线的激励效果能持续一天。参与者说,如果他们早上接触了明亮的强蓝光,晚上就不会觉得太困,而且反应速度维持不变,并没有随着时间推移而下降。另外,明亮的晨光似乎还能减缓生物钟对晚间蓝光的对抗。这项发现也符合当前光线如何影响人体生物钟和睡眠的数学模型。

It supports the idea that brighter and blue-enriched morning light could be a useful countermeasure to artificial light in the evenings especially during the darker seasons, when less daylight is available. It means we don't necessarily need to spend our evenings in darkness, or stop using our computers and gadgets.

这就支持了这样一个观点,明亮的强蓝晨光可以有效替代晚间人造光,尤其是在日光不足、天色较暗的季节。也就是说,夜晚不一定非要在黑暗中度过,也不用非要关掉电脑和别的小工具。

“The effects of light in the evening highly depend on the light you were exposed to in the morning,” says Dieter Kunz, who was involved in the study. “When we’re talking about kids looking at iPads in the evening, it’s having detrimental effects if they’re spending their daytimes in biological darkness. But if they’re in bright light during the day it may not matter.”

参与这项研究的昆兹(Dieter Kunz)说,“夜晚灯光对人的影响很大程度上取决于早上接触的光线。谈到孩子们晚上看平板电脑,如果他们白天完全没照射到阳光,那就会产生不良影响,但如果白天接触了明亮的日光,那可能就没关系。”

It’s ridiculously simple. But spending more time outdoors during the daytime and dimming the lights in the evening really could be a recipe for better sleep and health. For millennia, humans have lived in synchrony with the Sun. Perhaps it's time we got reacquainted.

说起来简单到荒谬。不过白天多待在户外,晚上调暗灯光,的确是获得良好睡眠和健康的秘诀。几千年来,人们都是日出而作、日落而息。也许是时候重新认识这一点了。

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