常上夜班干擾身體節律 對腸胃破壞極大

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.
科學家們聲稱，上夜班可能會干擾身體的自然節律，從而導致大腦和消化系統變得完全格格不入。

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.
研究人員發現，連續三個夜班對大腦中的身體主時鐘沒有多少影響，但它對腸胃功能造成了巨大破壞，讓有關的自然週期出現了整整12小時的偏差。

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.
這些發現凸顯了夜班對自然節律（負責管理人體各個器官與系統）的不同生物鐘的巨大影響。

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.
人體內部有關白天與黑夜的不一致性，或許可以解釋爲什麼上夜班和倒時差的人可能出現胃痛或其他腸胃問題。一旦他們的身體有時間進行調整，這些症狀就會消失。

"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.
美國華盛頓州立大學睡眠與體能研究中心主任漢斯·範東恩表示：“進行跨時區旅行時，人們最先出現的症狀之一是胃腸不適。這是因爲，此時胃腸的生物鐘同人體中央生物鐘之間的同步性被打亂了。”

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.
爲了進行這項研究，範東恩邀請了14名健康的志願者（年齡在22-34歲之間）進入他的實驗室，並把他們分成兩組。第一組模擬上三天白班的情形。這組志願者可以在晚上10點到次日早上6點睡覺。第二組志願者則連續3個夜晚保持清醒，他們只能在上午10點到下午6點睡覺。

Over the next 24 hours, scientists took the volunteers' blood every three hours and sent the samples to the University of Surrey for analysis.
在接下來的24小時中，科學家每3小時採集一次志願者的血樣，並將這些血樣送到英國薩里大學作分析。

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.
在薩里大學，研究人員測量了褪黑素和皮質醇的水平。這兩種荷爾蒙會根據身體的主時鐘增加和減少。研究人員還測量了同消化有關的代謝物的水平。

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.
結果顯示，連續3個夜班讓大腦的主時鐘縮短了平均大約兩小時。但消化系統的生物鐘受到的影響是深遠的，夜班讓它縮短了12小時。

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.
我們的大腦中有一箇中央主時鐘，它會根據周圍光線的變化來控制人們何時醒來和入睡。不過，包括消化系統在內的身體很多其他器官有自己的生物鐘。

"When we looked at the data we saw the massive twelve hour shifts," said Van Dongen.
範東恩說稱：“當我們查看數據時，我們看到了大規模的12小時的轉換。”

The night shifts also disrupted the rhythms of two metabolites linked to chronic kidney disease.
此外，夜班還會干擾與慢性腎病有關的兩種代謝物的節律。

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.
該研究的第一作者、薩里大學神經內分泌學教授德布拉·斯基恩稱，這些發現將幫助科學家更多瞭解輪班工作可能造成的損害。