好英语网上夜班损害哪些人的身心健康？
In some jobs, working the night shift is unavoidable. There are hospitals to run, planes to fly and shops to keep open as we move towards a 24-hour society. With careful planning and a bit of peace during the daytime, it is possible to work all night and still get eight hours sleep the follow day. Some people will even tell you they don’t mind and that they get used to working in this way. But can their bodies ever become fully accustomed to working to a clock turned upside down? And, more worryingly, is nocturnal labour bad for your health?
对有些工作而言，上夜班在所难免。随着人类社会朝着24小时连轴转的方向发展，这意味着，在夜晚，医院要正常运转，航班要正常飞行，商店要照常营业。其实只要安排周密，白天片享片刻安静，人们可以在彻夜工作后，第二天再补足8小时睡眠。有些人甚至会说，他们不介意夜班，而且也已经适应了这种工作方式了。但是他们的身体真的能完全适应昼夜颠倒的作息时间么？更令人担忧的是，夜间工作会不会带来一些对健康不利的影响呢？
There are two elements to these questions. One is about how we feel – our mental wellbeing. People are right to say they get used to shift work. There’s evidence that we cope with subsequent night shifts better than the first of a series, but some people find it much harder than others.
这些问题可以分成两方面来回答。一方面是人们自身感受如何，也就是心理健康状况。一些人说自己习惯上夜班，他们这么说是有道理的，因为证据表明，上完一段时间的夜班后，接下来的夜班就比较可以轻松应对，但是另外也有一些人的很难习惯上夜班。
A Canadian study monitored the timing of the sleep, the light levels and the quantity of the sleep hormone melatonin produce by a small group of police officers as they embarked on a week of night shifts. Usually we release melatonin late in the evening when we start feeling tired and ready for bed. If you’ve adapted well to working nights, the peak will move to daytime instead. In this study, those whose pattern of melatonin production showed they had made that adjustment felt happier and more alert, as well as showing faster reaction times – but only 40% managed to make the switch.
加拿大的一项科学调查针对一小部分警察进行了研究。在警察连续值一周夜班的期间，研究人员持续对他们的睡眠时间、环境的光强度和体内分泌的睡眠荷尔蒙褪黑素的水平进行了监测。深夜，人们开始感觉疲倦并打算上床睡觉，人体通常会在这时分泌褪黑素。如果一个人已经很适应晚上工作，褪黑素的峰值就会出现在白天。研究中，褪黑素分泌模式已经转变的警察感觉更开心，值夜班时也更警惕，而且反应时间也更短，不过调查发现只有40%的警察褪黑素的分泌模式发生了转变。
In a larger study of more than 3,000 police officers working shifts in Canada and the US, the consequences for those who were unable to adjust were clear, with 40% diagnosed with some kind of sleep disorder.
另外一项规模更大的研究涵盖了加拿大和美国的3,000多名夜班警察，对于无法适应夜班的警察来说，后果很明确，他们中有40%确诊出现了某种睡眠紊乱症状。
Even if you do feel OK, there’s also the question of whether your body could be suffering in the long-term. When it comes to assessing the physiological effects, one of the problems is differentiating between the impact that shift work might have on your lifestyle from the direct impact of working during the night. It is harder to eat healthily or to exercise regularly if you’re working shifts. Not only is a salad harder to obtain during the night, but it’s probably not what you feel like when you’re trying to keep yourself awake. This tempts people towards snacks and takeaways. Pizza and curry may be convenient and make you feel better, but of course eating them every night isn’t very healthy. There’s also less opportunity for exercise. While you might manage to drag yourself to the gym at the end of a day’s work, it’s that much harder to do that at the end of your shift if you’re already been up all night and are yearning for a nap.
即便你的心理感觉状况良好，但是长时间的夜班生活会不会对你的身体造成伤害也是一个问题。研究熬夜对人体生理造成的影响时，科学家面临一些难题，其中之一就是，如何区分夜班导致生活方式改变而产生的间接影响，和夜间工作产生的直接影响。上夜班的人更难保持饮食健康和规律运动。这不仅是因为大半夜色拉不好找，而且当一个人想努力保持清醒的时候，恐怕也不太想吃色拉。这让人们在晚上更愿意吃快餐和外卖。匹萨和咖喱吃起来方便，而且吃完也能让人感觉更开心，不过每天晚上都吃这个肯定不怎么利于健康。上夜班也会导致运动机会减少。忙活了一个白天之后，你也许还能逼自己去健身房运动一下，但若是你已经熬了一个通宵，下班之后哈欠连天，再去健身房练练就要难多了。
Airline pilots were found to be happier on the days they were resting compared with those where they worked early or late shifts. Of course it’s not unusual to prefer your day off to the days you have to get up and go to work, regardless of the time. But the researchers also found that when the pilots worked the early shift they had higher levels of the stress hormone cortisol on waking and produced more cortisol throughout the day. In the long-term, high levels are thought to be associated with an increased the risk of heart problems and high blood pressure.
研究发现，与早班或晚班飞行任务相比，航空公司的飞行员在休息日的时候心情更好。不论是飞早班或飞晚班，一般人肯定更喜欢休息而不是从床上爬起来去工作。但是，研究人员同时发现，飞早班的飞行员醒来时体内的压力激素皮质醇水平更高，而且一整天都会分泌更多皮质醇。人们认为，长期皮质醇水平偏高可能导致患心脏疾病和高血压的风险提高。
There could be other consequences too. One study found that a single overnight shift is enough to increase your blood pressure.
不良后果不止于此。一项研究表明，上一个夜班就足以让人血压升高。
Add to this research from the University of Surrey published earlier this year: it demonstrated that after just three days of night shifts, the expression of genes was disrupted, meaning that they began to be active at the wrong time of day. Around 6% of our genes are set to work at specific times, but after just a few days keeping strange hours this pattern was easily disturbed. And a different study found that, after five weeks, people who stayed awake at night and slept during the day showed impaired glucose regulation and changes in metabolism which could increase the risk of type 2 diabetes and obesity in the long-term.
此外，今年早些时候，萨里大学（University of Surrey）发表了一项研究，结果表明，上三个夜班之后，人体的基因表达会出现紊乱，也就是说，基因开始在错误的时间被激活。人体约6%的基因会在特定的时间被激活，但是经过几天的颠倒作息，这种模式很容易就被打乱了。另一项研究发现，经历5周昼伏夜出的作息后，人体血糖调节能力受损，人体新陈代谢也发生了变化，长期来看，这会导致II型糖尿病和肥胖症风险上升。
Of course these studies were all short-term, raising the possibility that perhaps our bodies adjust in the long-term, but results of epidemiological studies conducted over many years are on the whole discouraging. There has been some debate about the impact of shift work on the risk of cardiovascular disease, with many studies finding it raises the risk and a few finding it doesn’t. But the largest synthesis of the research to date, published in 2012, did show an increased risk of heart attacks in people working shifts. Even when lifestyle was controlled for, people doing shifts were still put at higher risk.
当然，这些都是短期研究，时间拉长之后人体可能会出现相应的调节机制，但是多年的流行病学研究结果总体上并不支持这种观点。关于轮班制工作对心血管疾病风险的影响，学界有诸多争论。许多研究结果发现上夜班会增加患病风险，而少数研究则发现不增加患病风险。但是发表于2012年的至今最长的一篇综述表明，轮班制工作的人群患心脏病的风险较高。即便将生活方式加以控制，倒班人群仍旧有较高的患病风险。
But when it comes to metabolic syndrome – an umbrella term including obesity, raised glucose levels, increased blood pressure, and high cholesterol levels – it was lifestyle that seemed to be key. If people worked night shifts, but succeeded in exercising regularly, eating healthily and not smoking, there was less evidence of an increased risk, despite their unsocial hours.
代谢综合征是对肥胖、高血糖、高血压、高胆固醇等疾病的总称。对于代谢综合征来说，生活方式反而似乎是最重要的风险因素。如果上夜班的人能够保证规律运动、饮食健康和远离香烟，尽管工作时间不正常，但患代谢综合征的风险提高并不明显。
There’s also evidence of increased risk of breast cancer in those who work night shifts, with a greater impact in those who are ‘larks’, who spring out of bed early in the morning, but find it hard to stay up late at night.
上夜班的人也有较高的患乳腺癌风险，尤其对于习惯早睡早起的人来说，上夜班所产生的影响更大。
What these large scale epidemiological studies can’t tell us is which individuals are most likely to be affected. Is it the case that as with the short-term studies, some people adapt and that those people won’t suffer long-term effects? Or are there risks for everyone working shifts?
但是这些大规模的流行病学研究无法告诉人们，哪类人更容易受夜班影响。是不是就像短期研究显示的那样，有些人的生理能够适应，而那些生理上无法调整的人就会受到长期影响？还是说所有上夜班的人都会面临风险？
Research is complicated by the many forms of shift work people undertake. Working late every so often is likely to have different effects on the body from having the clock turned upside down by working several overnight shifts a week.
人们的夜间工作形式多样，提高了相关研究的难度。与一周只有几天昼夜颠倒地上夜班相比，频繁的夜班工作可能会对人体产生不同的影响。
Still, until we know more about exactly who is at risk, those who work at night would be wise to take every opportunity they can to eat healthily, to exercise and to look out for early signs of these diseases.
不过，在人们能准确地知道什么样的人上夜班有损健康之前，从事夜间工作的人应该尽量保证饮食健康、规律运动，并且留意有没有出现这些疾病的早期症状。