研究發現：週末補覺補的是肥肉 損的是健康

也許你已經習慣了平時缺覺週末補，但是新研究表明，週末補覺彌補不了連續多日缺覺對身體的傷害，更糟糕的是，週末補覺其實補的不是健康，而是肥肉。你還敢補覺嗎？

A new study says the habit of sleeping in on weekends may not be such a good idea for your waistline -- or your health.

一項新研究表明，週末睡懶覺的習慣可能對你的身材和健康都沒有好處。

sleep in: 睡懶覺；睡過頭

"Weekend catch-up sleep is not protective," said Dr. Vsevolod Polotsky, director of sleep research at the Johns Hopkins University School of Medicine. "The bottom line of this study is that even if you sleep longer on weekends, if you continue to sleep poorly, you will still eat too much, and you will still gain weight."

約翰霍普金斯大學醫學院睡眠研究中心的主任弗謝沃洛德·波洛茨基博士說：“週末補覺對身體起不到保護作用。這項研究的結果是，即使你在週末多睡覺，但如果接下來你還是缺覺，那麼你還是會過度進食，還是會增重。”

"Sleeping in on the weekends doesn't correct the body's inability to regulate blood sugar if that weekend is followed by a workweek or school week full of insufficient sleep," said study author Kenneth Wright Jr., who directs the sleep lab at the University of Colorado in Boulder.

該研究的作者、科羅拉多大學波德分校睡眠實驗室主任小肯尼斯·賴特說：“如果週末補覺後，在工作日或上學日又連續多天睡眠不足，那麼週末補覺不能改善身體無力調節血糖的狀況。”

"And when we go back to getting too little sleep again," Wright said, "we're doing things that could be negative for our health long-term."

賴特說：“週末補覺、平時缺覺，長遠來看對健康有害。”

缺覺導致過度進食

The American Academy of Sleep Medicine recommends at least seven hours of sleep each night for adults and much more for children.

美國睡眠醫學會建議，成人每晚至少睡7個小時，兒童需要的睡眠時間比這更多。

The study, published in the journal Current Biology, assigned 36 healthy young men and women to three groups that had different sleep requirements over a total of 10 days. None of the participants had newborns in the home or any health impairments that would affect the quality of their sleep.

發表在《當代生物學》期刊上的這項研究將36名健康的年輕男性和女性分成三組，每一組在10天內按照不同的要求來睡眠。這些參與者家裏都沒有新生兒，也沒有任何會影響睡眠質量的疾病。

The first group had the opportunity to sleep for nine hours each night for the 10 days. The second group was restricted to only five hours of sleep a night for the same duration, while the third was restricted to five hours Monday through Friday but allowed to sleep as long as they wanted on the weekend and go to bed as early as they liked on Sunday night. Come Monday, that third group was put back on the deprived sleep schedule of only five hours a night.

第一組人有機會在10天內每晚睡9個小時，第二組人在10天內每晚只能睡5個小時，第三組人週一到週五每晚只能睡5個小時，但週末可以愛睡多久睡多久，週日晚上也可以想多早上牀就多早上牀。到了週一，第三組又要回到每晚睡5個小時的缺覺狀態。

Both of the sleep-deprived groups snacked more after dinner and gained weight during the study, men much more than women. The sleep-deprived men showed a 2.8% increase in their weight, while women's body size went up by only 1.1%; men who slept in on the weekend showed a 3% increase in weight, while women's body size went up 0.05%.

缺覺的兩組人在吃完飯後都會吃更多零食，而且研究期間體重增加，男性體重增加比女性明顯得多。缺覺的男性體重增加2.8%，女性體重增加幅度則只有1.1%。週末補覺的男性體重增加3%，女性則增重0.05%。

Gaining weight while sleep-deprived isn't surprising, Wright said.

賴特說，缺覺期間體重增加並不意外。

"One of the things we and others have found in the past is that when people don't sleep enough, they tend to eat more, partly because their body is burning more calories. But what happens is that people eat more than they need and therefore gain weight."

“過去的研究結果發現，當人們缺覺時，通常會吃得更多，部分原因是身體消耗了更多熱量。但實際上是因爲人們過度進食從而導致體重增加。”

That could be in part, Polotsky said, because hunger hormones are affected by a chronic lack of sleep.

波洛茨基說，過度進食的部分原因可能是因爲飢餓激素受長期缺覺影響。

"The hormone leptin decreases appetite, while the hormone ghrelin increases appetite," explained Polotsky, who was not involved in the study. "We know from previous research that sleep deprivation causes leptin to drop and ghrelin to rise, so you're hungry."

沒有參與該研究的波洛茨基解釋說：“瘦素會令食慾減退，而飢餓激素則會令食慾增加。從先前的研究得知，缺覺會導致瘦素水平下降，飢餓激素水平上升，所以會感到飢餓。”

補覺補不了缺覺對身體的傷害

What was surprising is what happened to the group who slept in on weekends.

讓人驚訝的是週末補覺組的結果。

"Even though people slept as much as they could, it was insufficient," Wright said. "As soon as they went back to the short sleep schedules on Monday, their ability of their body to regulate blood sugar was impaired."

賴特說：“儘管人們在週末想睡多久就睡多久，但還是不足以彌補失去的睡眠。週一回到缺覺模式後，身體調節血糖的能力就會受到損害。”

Not only that, but the weekend recovery group showed increased sensitivity to insulin in both their muscles and their livers, a result not found in the second group on restricted sleep. That's important, Wright said, because the muscle and liver are two of the most important tissues that take up blood sugar after eating.

不僅如此，研究顯示，週末補覺組的肌肉和肝臟對胰島素都變得更敏感了，這一結果是缺覺的第二組中沒有發現的。賴特說，這個發現很重要，因爲肌肉和肝臟是進食後吸收血糖的最重要的兩個器官。

"That helps us understand why is it that when we don't get enough sleep, we have an increased risk for things like diabetes," he added, because "short, insufficient sleep schedules will lead to an inability to regulate blood sugar and increases the risk of metabolic disease in the long term."

賴特補充道，“這有助於理解爲什麼睡眠不足時糖尿病等疾病的風險會增加”，因爲“缺覺會導致身體無力調節血糖，長遠來看會增加代謝性疾病的風險。”

Metabolic syndrome is an array of symptoms such as fat around the waist, abnormal cholesterol, high blood sugar and high blood pressure, all of which can raise the risk of heart disease, stroke and diabetes.

代謝綜合徵包括一系列症狀，比如腰間脂肪堆積、膽固醇異常、高血糖、高血壓，所有這些都會提高心臟病、中風和糖尿病風險。

生物鐘紊亂

One of the reasons the weekend group may have been more affected is because their circadian rhythm, or biological clock, had been altered, depriving the body of certain hormones.

週末補覺組受的影響更大，其中一個原因是他們的生物鐘被打亂了，導致身體的某些激素喪失。

"If you catch up during weekends, you habitually eat later, because the circadian clock is shifting," Polotsky said. "Add in after-dinner snacks; the sleep-deprived eat much more after dinner, as well."

波洛茨基說：“如果你在週末補覺，你通常會更晚進食，因爲生物鐘往後推了。還有飯後零食，缺覺者在飯後吃的零食會多得多。”

So what's a sleep-deprived person to do if a catch-up over the weekend isn't a good option? Polotsky sums it up in two words: "Sleep longer."

如果週末補覺不是個好選擇，那麼缺覺的人應該怎麼做呢？波洛茨基的答案只有三個字：多睡覺。