也许你已经习惯了平时缺觉周末补，但是新研究表明，周末补觉弥补不了连续多日缺觉对身体的伤害，更糟糕的是，周末补觉其实补的不是健康，而是肥肉。你还敢补觉吗？
A new study says the habit of sleeping in on weekends may not be such a good idea for your waistline -- or your health.
一项新研究表明，周末睡懒觉的习惯可能对你的身材和健康都没有好处。
sleep in: 睡懒觉；睡过头
"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."
约翰霍普金斯大学医学院睡眠研究中心的主任弗谢沃洛德·波洛茨基博士说：“周末补觉对身体起不到保护作用。这项研究的结果是，即使你在周末多睡觉，但如果接下来你还是缺觉，那么你还是会过度进食，还是会增重。”
"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.
该研究的作者、科罗拉多大学波德分校睡眠实验室主任小肯尼斯·赖特说：“如果周末补觉后，在工作日或上学日又连续多天睡眠不足，那么周末补觉不能改善身体无力调节血糖的状况。”
"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."
赖特说：“周末补觉、平时缺觉，长远来看对健康有害。”
缺觉导致过度进食
The American Academy of Sleep Medicine recommends at least seven hours of sleep each night for adults and much more for children.
美国睡眠医学会建议，成人每晚至少睡7个小时，儿童需要的睡眠时间比这更多。
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.
发表在《当代生物学》期刊上的这项研究将36名健康的年轻男性和女性分成三组，每一组在10天内按照不同的要求来睡眠。这些参与者家里都没有新生儿，也没有任何会影响睡眠质量的疾病。
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.
第一组人有机会在10天内每晚睡9个小时，第二组人在10天内每晚只能睡5个小时，第三组人周一到周五每晚只能睡5个小时，但周末可以爱睡多久睡多久，周日晚上也可以想多早上床就多早上床。到了周一，第三组又要回到每晚睡5个小时的缺觉状态。
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%.
缺觉的两组人在吃完饭后都会吃更多零食，而且研究期间体重增加，男性体重增加比女性明显得多。缺觉的男性体重增加2.8%，女性体重增加幅度则只有1.1%。周末补觉的男性体重增加3%，女性则增重0.05%。
Gaining weight while sleep-deprived isn't surprising, Wright said.
赖特说，缺觉期间体重增加并不意外。
"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."
“过去的研究结果发现，当人们缺觉时，通常会吃得更多，部分原因是身体消耗了更多热量。但实际上是因为人们过度进食从而导致体重增加。”
That could be in part, Polotsky said, because hunger hormones are affected by a chronic lack of sleep.
波洛茨基说，过度进食的部分原因可能是因为饥饿激素受长期缺觉影响。
"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."
没有参与该研究的波洛茨基解释说：“瘦素会令食欲减退，而饥饿激素则会令食欲增加。从先前的研究得知，缺觉会导致瘦素水平下降，饥饿激素水平上升，所以会感到饥饿。”
补觉补不了缺觉对身体的伤害
What was surprising is what happened to the group who slept in on weekends.
让人惊讶的是周末补觉组的结果。
"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."
赖特说：“尽管人们在周末想睡多久就睡多久，但还是不足以弥补失去的睡眠。周一回到缺觉模式后，身体调节血糖的能力就会受到损害。”
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.
不仅如此，研究显示，周末补觉组的肌肉和肝脏对胰岛素都变得更敏感了，这一结果是缺觉的第二组中没有发现的。赖特说，这个发现很重要，因为肌肉和肝脏是进食后吸收血糖的最重要的两个器官。
"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."
赖特补充道，“这有助于理解为什么睡眠不足时糖尿病等疾病的风险会增加”，因为“缺觉会导致身体无力调节血糖，长远来看会增加代谢性疾病的风险。”
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.
代谢综合征包括一系列症状，比如腰间脂肪堆积、胆固醇异常、高血糖、高血压，所有这些都会提高心脏病、中风和糖尿病风险。
生物钟紊乱
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.
周末补觉组受的影响更大，其中一个原因是他们的生物钟被打乱了，导致身体的某些激素丧失。
"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."
波洛茨基说：“如果你在周末补觉，你通常会更晚进食，因为生物钟往后推了。还有饭后零食，缺觉者在饭后吃的零食会多得多。”
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."
如果周末补觉不是个好选择，那么缺觉的人应该怎么做呢？波洛茨基的答案只有三个字：多睡觉。
