常上夜班干扰身体节律 对肠胃破坏极大

Working night shifts can mess up the body's natural rhythms so much that the brain and digestive system end up completely out of kilter with one another, scientists say.

科学家们声称，上夜班可能会干扰身体的自然节律，从而导致大脑和消化系统变得完全格格不入。

Three night shifts in a row had little impact on the body's master clock in the brain, researchers found, but it played havoc with gut function, throwing the natural cycle out by a full 12 hours.

研究人员发现，连续三个夜班对大脑中的身体主时钟没有多少影响，但它对肠胃功能造成了巨大破坏，让有关的自然周期出现了整整12小时的偏差。

The finding highlights the dramatic impact that night shifts can have on the different clocks that govern the natural rhythms of organs and systems throughout the human body.

这些发现凸显了夜班对自然节律（负责管理人体各个器官与系统）的不同生物钟的巨大影响。

Internal disagreements over night and day may explain why people on night shifts, and those with jet lag, can suffer stomach pains and other gut problems, which clear up once their body has had time to adjust.

人体内部有关白天与黑夜的不一致性，或许可以解释为什么上夜班和倒时差的人可能出现胃痛或其他肠胃问题。一旦他们的身体有时间进行调整，这些症状就会消失。

"One of the first symptoms people experience when traveling across time zones is gastrointestinal discomfort and that's because you knock their gut out of sync from their central biological clock," said Hans Van Dongen, director of the Sleep and Performance Research Center at Washington State University.

美国华盛顿州立大学睡眠与体能研究中心主任汉斯·范东恩表示：“进行跨时区旅行时，人们最先出现的症状之一是胃肠不适。这是因为，此时胃肠的生物钟同人体中央生物钟之间的同步性被打乱了。”

For the study, Van Dongen invited 14 healthy volunteers aged 22 to 34 into his sleep lab and split them into two groups. The first spent three days on a simulated day shift and could sleep from 10pm to 6am each night. Those in the second group stayed awake for three nights in a row and were only allowed to sleep from 10am to 6pm.

为了进行这项研究，范东恩邀请了14名健康的志愿者（年龄在22-34岁之间）进入他的实验室，并把他们分成两组。第一组模拟上三天白班的情形。这组志愿者可以在晚上10点到次日早上6点睡觉。第二组志愿者则连续3个夜晚保持清醒，他们只能在上午10点到下午6点睡觉。

Over the next 24 hours, scientists took the volunteers' blood every three hours and sent the samples to the University of Surrey for analysis.

在接下来的24小时中，科学家每3小时采集一次志愿者的血样，并将这些血样送到英国萨里大学作分析。

There, researchers measured levels of hormones called melatonin and cortisol, which rise and fall according to the body's master clock, along with levels of metabolites linked to digestion.

在萨里大学，研究人员测量了褪黑素和皮质醇的水平。这两种荷尔蒙会根据身体的主时钟增加和减少。研究人员还测量了同消化有关的代谢物的水平。

The results showed that three night shifts in a row moved the brain's master clock by about two hours on average. But the impact on the digestive system's clock was profound, with the stint of night shifts knocking it out by 12 hours.

结果显示，连续3个夜班让大脑的主时钟缩短了平均大约两小时。但消化系统的生物钟受到的影响是深远的，夜班让它缩短了12小时。

Our bodies have a central master clock in the brain that draws on changes in ambient light to control when we wake up and when we fall asleep. But many other organs in the body have their own biological clocks, including the digestive system.

我们的大脑中有一个中央主时钟，它会根据周围光线的变化来控制人们何时醒来和入睡。不过，包括消化系统在内的身体很多其他器官有自己的生物钟。

"When we looked at the data we saw the massive twelve hour shifts," said Van Dongen.

范东恩说称：“当我们查看数据时，我们看到了大规模的12小时的转换。”

The night shifts also disrupted the rhythms of two metabolites linked to chronic kidney disease.

此外，夜班还会干扰与慢性肾病有关的两种代谢物的节律。

Debra Skene, the first author on the study and professor of neuroendocrinology at the University of Surrey, said the findings will help scientists to learn more about the harms that shift work can cause.

该研究的第一作者、萨里大学神经内分泌学教授德布拉·斯基恩称，这些发现将帮助科学家更多了解轮班工作可能造成的损害。