Do you often feel tired in the morning even though you’ve beenin bed for seven or eight hours the night before? Like manypeople, you are not sleeping as much as you think you are. Inother words, your sleep efficiency is not that good.

　　你是不是常常觉得即使晚上已经睡了七八个小时，白天依旧无精打采?你不是一个人，很多人都和你一样，因为你的(有效)睡眠时间并没有你想象的那么长。简言之，你的睡眠质量不够高。

　　Sleep experts define “sleep efficiency” as the percentage of time lying down that you are actuallysleeping.

　　睡眠专家对“睡眠效率”的定义是真正睡眠时间占你躺在床上时间的比例。

　　According to explanatory journalism website vox.com, the science of sleep efficiency is still young.There is no specific number for efficiency that’s been proven as linked to poor health. However,according to a New York Times report about sleep quality, some experts estimate a rough ballparkof 85 percent or above as a decent place to be.

　　据解释性新闻网站vox.com的报道，关于睡眠质量的研究起步较晚。目前，尚无具体比例说明(多低的)睡眠效率将会有害健康。但是，据《纽约时报》报道，一些专家认为如果想要保持良好状态，这一比例约为85%或更高。

　　Besides avoiding caffeine intake after lunch and refraining from doing physical exercise before bed,here are more tips for improving sleep efficiency, curated from news website Vox and Quartz.

　　除了午餐后不摄入咖啡因、睡前避免体育运动之外，Vox与Quartz网站还为大家提供了一些提高睡眠质量的小建议，一起来看吧!

　　Avoid blue light at night

　　夜晚避免蓝光

　　Short wavelength blue light, emitted by the sun and by the screens of computers, iPads andsmartphones, stops production of the sleep-inducing hormone melatonin and makes you feel morealert. Blue light tells your brain it’s daytime. Experts suggest turning off your computers andsmartphones one hour or at least 30 minutes before bed. You can also try installing apps thatcan filter blue light on your devices. Both F.lux for computer and Bluelight Filter for Android phoneswork fine.

　　来自太阳光、电脑屏幕、平板电脑或手机屏幕的短波长蓝光都会抑制促进睡眠的褪黑色素的产生，让你毫无睡意。蓝光会让你的大脑误认为此时还是白天。专家们的建议是：至少在入睡前半小时、最好是一小时关掉你的电脑和手机。你也可以在电子设备里下载一些能过滤蓝光的APP，比如可用于电脑的F.lux和用于安卓手机的Bluelight Filter。

　　Keep a consistent sleep schedule

　　保持相同的入睡与起床时间

　　Go to bed and wake up at the same time, or relatively the same time, every day. Avoid bingesleeping on the weekend. Consistency is key to a good night’s sleep, especially when it comes towaking up. When you have a consistent wake-up time, your brain acclimates to this and movesthrough the sleep cycle in preparation for you to feel rested and alert at your wake-up time.Roughly an hour before you wake, hormone levels increase gradually (along with your bodytemperature and blood pressure), causing you to become more alert.

　　每天最好在同一个时间入睡和起床，至少保持相对的一致性。不要在周末睡得太放纵，因为固定的睡眠时间，尤其是固定的清醒时间正是好睡眠的关键。当你拥有固定的睡眠时间时，你的大脑就会形成习惯，在入睡前为进入睡眠状态做好准备，在醒来时恢复清醒。一般在你醒来之前的一小时左右，你的褪黑色素水平会逐渐增加(你的体温与血压也会随之上升)，让你在醒来后更加清醒。

　　Take naps

　　眯一会

　　One of the biggest peaks in melatonin production happens during the 1 to 3 pm time frame, whichexplains why most people feel sleepy in the afternoon. If you aren’t getting enough sleep at night,you’re likely going to feel an overwhelming desire to sleep in the afternoon. When this happens,you’re better off taking a short nap (less than 30 minutes) than resorting to caffeine or strong teato keep you awake. A short nap will give you the rest you need to get through the rest of theafternoon, and you’ll sleep much better in the evening than if you drink caffeine or take a longafternoon nap.

　　褪黑素产生的高峰是每天下午1点至3点，这也是为什么大部分人会在下午感到困倦。如果你前一天晚上睡眠不足，那么你很可能在第二天下午完全被周公打败。这时，你最好的选择就是小眯一会(半个小时以内)。它比喝咖啡或是浓茶效果更好。与喝咖啡或是在下午睡很久相比，小眯一会不仅让你得到充分的休息，还能保证你当天晚上的睡眠。

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（编辑：何莹莹）