Weve all been there： Its been a long week at work， so Friday night， you reward yourself by going to bed early and sleeping in. But when you wake up the next morning （or afternoon）， light scathes your eyes， and your limbs feel like theyre filled with sand. Your brain is still lying down and you even have faint headache. If too little sleep is a problem， then why is extra sleep a terrible solution？

Over sleeping feels so much like a hangover that scientists call it sleep drunkenness. But， unlike the drunkenness damage caused byalcohol， your misguided attempt to stock upon rest makes you feel sluggish by confusing the part of your brain that controls your bodys daily cycle.

Your internal rhythms are set by your circadian pacemaker， a group of cells clustered in the hypothalamus， a primitive little part of the brain that also controls hunger， thirst， and sweat， Primarily triggered by light signals from your eyes， the pacemaker figures out when its morning and sends out chemical messages keeping the rest of the cells in your body on the same clock.

Scientists believe that the pacemake revolved to tell the cells in our bodies how toregu late their energy on a daily basis. When you sleep too much， youre throwing off that biological clock， and it starts telling the cells a different story than what theyre actually experiencing， inducing a sense of fatigue. You might be crawling out of bed at 11 a.m.， but your cells started using their energy cycle at seven. This js similar to how jet lag works.

But oversleeping isnt just going to ruinyour Saturday hike. If youre oversleeping onthe regular， you could be putting yourself atrisk for diabetes， heart disease， and obesity. Harvards massive Nurses Health Study found that people who slept 9 to 11 hours a night developed memory problems and were more likely to develop heart disease than people who slept a solid eight（undersleepers are atan even bigger risk）. Other studies have linked oversleeping to diabetes， obesity， and evenearly death， Oversleeping doesnt just happen as amisgui ded attempt at rewarding yourself. The Harvard Nurses Study estimated that chronicover sleeping affects about 4 percent of the population. These are generally people who work odd hours， have an uncomfortable sleepsituation， or a sleeping disorder.

People who work early morning or overnight shifts might be oversleeping to compensate for waking up before the sunrises or going to sleep when its light out. Doctors recommend using dark curtains and artificial lights to straighten things out rather than medication or supplements. Apps likethe University of Michigans Entrain can also help people reset their circadian clock bylogging the amount and type of light they get throughout the day.

When you go to bed， your body cycles between different sleep stages. Your muscles， bones， and other tissues do their repair work during deep sleep， before you enter REM. However， if your bed or bedroom is uncomfortable too hot or cold， messy， orlumpy your body will spend more time in light， superficial sleep. Craving rest， youll sleeplonger.

If everythings just fine with your sleepzone but you still cant get under the eight-hour mark， you might need to go see a doctor. It could be a symptom of narcolepsy， which makes it hard for your body to regulate fatigue and makes you sleep in more. Sleep apnea is a potentially more serious disorder where you stop breathing while you slumber. Its typicallycaused by an obstructed airway， which leads to snoring. However， in a small number of sufferers， the brain simply stops telling the muscles to breathe， starving the brain andeventually forcing a gasping response. Inaddition to all the other terrifying aspects of this disease， its not doing your quality of sleep anyfavors.

No surprise， drugs and alcohol might also be causing you to sleep too much， asdoes being depressed （in fact， oversleeping can contribute to even more depression）. But no matter whats causing it， too much sleep is not good for your long-term health. Ratherthan kicking the can down the road， try getting some equilibrium between your weekend andweekday sleep.

很多人都有過這種經(jīng)歷：經(jīng)過一周的辛苦工作，好不容易捱到周五，為了犒勞自己早早爬上床，然后睡個懶覺。然而，當你第二天上午（或下午）起床時，卻感覺光線刺眼，四肢像灌了鉛一般。大腦昏昏沉沉，甚至感覺頭部隱隱作痛。如果說睡眠不足是個問題，那么為什么多睡卻是個糟糕的解決辦法呢？

過度睡眠之后的感覺很像宿醉，科學家把這稱之為“睡醉”。但是，與酒精會造成嚴重的神經(jīng)損害不同，你囤積睡眠的錯誤做法攪亂了大腦控制日常身體循環(huán)的部分，從而讓你感覺無精打采。

你的生理節(jié)奏由體內的“晝夜節(jié)律控制器”，即一組聚集在下丘腦的細胞群設定。下丘腦是人大腦中原生的一小部分區(qū)域，控制人的饑餓感、口渴感和流汗。眼睛接收到光線信號后，“晝夜節(jié)律控制器”隨之啟動并感覺到現(xiàn)在是早上，然后發(fā)出化學信號，讓你身體其余的細胞保持同樣的節(jié)奏。

科學家們認為，“晝夜節(jié)律控制器”進而指示體內細胞如何每日調節(jié)能量。如果你睡得太多，你的生物鐘就發(fā)生了變化，“晝夜節(jié)律控制器”便開始向細胞發(fā)出與實際不符的信號，從而引起疲乏感。你可能上午11點才爬下床，但是你體內的細胞在早上7點就開始能量循環(huán)了。這與時差反應類似。

然而過度睡眠破壞的可不止你周六的遠足。如果你經(jīng)常性地睡眠過多，就有可能患上糖尿病、心臟病和肥胖癥。哈佛大量的護士健康研究數(shù)據(jù)顯示：一晚上睡9到11個小時的人，比起長期睡夠8小時的人，更有可能出現(xiàn)記憶力的問題和心臟疾病（睡得更少的人則會有更大的問題）。其他研究表明：睡過頭與糖尿病、肥胖癥甚至早逝都有所關聯(lián)。

睡過頭可不僅僅是你犒勞自己的錯誤選擇。哈佛護士研究表明：長期睡過頭的人群占到總人口比重的4%。這些人一般睡覺時間不規(guī)律，入睡環(huán)境不舒服，或是有睡眠障礙。

一大早就開始工作的人還有上夜班的人，可能會為了天不亮就起床或者睡得太遲而補覺。醫(yī)生建議使用深色窗簾或人工照明去解決問題，不要吃藥或吃補品。手機應用可以通過記錄一天中接收到光線的量和類型，來幫助人們重新設定生物鐘——比如密歇根大學的“Entrain”。

當你睡覺時，你的身體會依次經(jīng)歷不同的睡眠階段。肌肉、骨骼還有其他軟組織都會在深度睡眠時進行修復工作，而在快速眼動睡眠階段則不會。但如果你的床或房間不舒服——太熱或太冷、雜亂無章或凹凸不平——你的身體更多處于淺睡眠狀態(tài)。由于對休息的需求，結果會導致你睡得更久一些。

如果你的睡眠區(qū)都沒什么問題，但身體還是無法獲得8小時的睡眠標識，那么你可能得去看醫(yī)生了。這可能是嗜睡癥的癥狀，這種病癥讓你的身體無法調節(jié)疲乏感，然后睡得更多。睡眠呼吸暫停綜合癥是一種更為嚴重的睡眠障礙，即在睡眠中暫停呼吸。這種情況通常是由于氣管內有阻礙所導致的，并導致打鼾。然而，對于一小部分患者而言，大腦只是停止發(fā)出讓肌肉呼吸的指令，使得大腦自身缺氧，最終導致呼吸困難。這種疾病除了所有駭人聽聞的方面以外，對睡眠質量也有所損害。

毫不奇怪，吸毒和喝酒同樣會讓你睡得過多，抑郁也會（事實上，過度睡眠又會進一步加重抑郁）。但是無論原因為何，過度睡眠對身體的長期健康都是沒什么好處的。別再用過度睡眠這種權宜之計了，試著保持工作日與周末的睡眠平衡吧。