(单词翻译:单击)
Popular opinion is that you should get eight hours of sleep a night,
人们普遍认为夜间睡眠时间应达到八小时，
but it might not actually be the number of hours you sleep, but the quality of your sleep that matters.
但（真正重要的）实际上并不是你的睡眠时间，而是你的睡眠质量。
Scientists aren't totally sure why we evolved to sleep.
科学家们还不能完全确定我们为什么会进化为需要睡眠的生物。
When we sleep we're unconscious to the world leaving us vulnerable to predators,
睡觉时，我们对周围世界失去知觉，这样我们很容易受到掠食者的侵袭，
but every species that has been studied in detail sleeps,
但是每一个被人类详细研究过的物种都睡觉，
so there's something beneficial to it!
所以睡觉肯定有某种好处！
Not sleeping well isn't just annoying, it's linked to poor overall health, lack of focus,
睡眠不好不只是烦人，它会导致整体健康状况不佳、注意力不集中，
memory loss, and Alzheimer's disease.
记忆丧失以及阿尔茨海默病。
Broadly speaking, there are two kinds of sleep,
广义上说，睡眠有两种类型，
non-rapid eye movement (NREM) and rapid eye movement (REM) sleep.
非快速眼动（NREM）睡眠和快速眼动（REM）睡眠。
Together they encompass the stages of sleep that are vital for feeling rested in the morning.
它们共同组成了睡眠阶段，这对我们早晨感觉精神饱满非常重要。
If sleep is cut short we don't go through all these phases.
如果睡眠不足，我们就不会经历所有这些阶段。
This can lead to anxiety, depression, fatigue, physical pain,
这会导致焦虑、抑郁、疲劳、身体疼痛，
and sleep disorders ranging from insomnia to hypersomnia, which is sleeping too much.
以及睡眠紊乱，失眠嗜睡，也就是睡眠过多。
Bad sleep can even stop us from forming memories.
糟糕的睡眠甚至会阻碍我们的记忆。
A new study looked at dendrites, branching outgrowths from neurons that carry electrical signals from synapses to the cell body.
一项关于树突的新研究展开。树突是一种神经元上的分支生长物，帮助进行从突触到细胞体电信号传输。
Activity in dendrites increases during sleep.
睡眠时树突活性增加。
That increase is linked to short and repetitive brain waves called spindles.
这种增加与短而具有重复性的脑电波，纺锤波有关。
These spindles peak at the beginning and end of a non-REM sleep cycle, the latter-end is marked by slow wave activity in the brain.
这些纺锤波在非REM睡眠周期的开始和结束时达到高峰，后者被脑中慢波活动标记。
During that peaking you're in a deep-sleep phase.
在高峰期间，你处于深度睡眠状态。
And without it, your memories suffer.
没有它，你的记忆就会受损。
So it's that deep-sleep phase right before REM sleep that we really need.
所以，我们真正需要的是REM睡眠前的深睡眠阶段。
The slow waves are associated with the most prominent brain activity during sleep.
慢波与睡眠中最显著的大脑活动有关。
They help transfer memories from the hippocampus to the prefrontal cortex where they are consolidated and stored.
它们有助于将记忆从海马体转移到前额叶皮层，从而加以巩固和储存。
These slow waves are also linked to attention in wakeful hours, heart health, metabolic regulation, and overall cognition.
人在清醒时，这些慢波也影响到注意力状态、心脏健康、代谢调控以及整体认知。
By the way, missing out on that deep sleep can be as simple as having anxiety.
顺便说一下，错过深睡眠也就意味着焦虑。
When we're stressed, our bodies are primed to respond to situations by waking up.
当我们感受压力时，我们的身体就准备保持清醒，来应对各种情况。
When you're stressed the amygdala's "fight or flight" response doesn't totally shut down.
当你感到紧张时，杏仁核的“战斗或逃跑”反应并没有完全停止。
This means, you can't enter that deep sleep restorative phase!
这意味着，你无法进入深度睡眠恢复期！
Without this restorative sleep, we don't restore our brain to a baseline condition.
如果没有这种恢复性睡眠，我们就无法使我们的大脑恢复到一个基线状态。
And over the years this adds up.
如果长年如此，这种状态就会累加。
The link between poor sleep and Alzheimer's isn't from a few bad nights,
睡眠不佳与阿尔茨海默病之间的联系不是源自几个糟糕的夜晚，
it's from YEARS of poor sleep that doesn't allow the brain to properly repair itself.
而是多年的不良睡眠积累，这会使得大脑无法现实适当的自我修复。
So what can you do? A lot of research points to sleep hygiene as a simple place to start.
那么你能做什么呢？众多研究表明，这一切可以从睡眠卫生简单开始。
The same way you shower to clean your body you want to clean your sleeping space.
就像你洗澡来清洁你的身体一样，你想清洁你的睡眠空间。
Establishing healthy sleep habits like avoiding caffeine in the afternoon,
养成健康的睡眠习惯，比如避免在下午喝咖啡因饮品，
not napping late in the day, keeping screens out of the bedroom,
如果时间已晚，就不要再小睡了，把带屏幕的东西都移出卧室，
and exposing yourself to light patterns that mimic your circadian rhythm.
让自己置身于与你生理节奏合拍的轻模式中。
Of course, the stresses that are keeping your brain from fully relaxing are less simple to fix,
当然，阻碍你大脑完全放松的压力，不那么容易放下，
but worth working on it if means healthy sleep for a healthy life.
但是如果健康的睡眠意味着健康的生活，那就值得一试。
If you like this video be sure to subscribe for more Seeker, we've got a so many videos on sleep!
如果你喜欢这个视频，请订阅更多Seeker视频，关于睡眠，我们有很多内容！
Click here to watch. You'll sleep better at night.
点击这里观看。晚上你会睡得更好。
And speak in of, did you know, some birds can sleep while flying by keeping part of their brain awake!
谈到，你知道吗？有些鸟能通过保持部分大脑清醒而在飞行中睡觉！
I wish I could do that.
我希望我能那样做。
