为什么我们需要睡觉——生命的三分之一
你有没有想过，当你闭上眼睛、躺在温暖的小床上做美梦的时候，你的身体里正在发生什么神奇的事情呢？也许你会觉得，睡觉只是因为我们累了，需要休息一下。但实际上，睡眠可远不止"休息"这么简单哦！科学家们经过几十年的研究发现，睡眠是一种非常复杂、非常重要的生命活动，它对我们的身体健康、学习能力、情绪管理甚至寿命长短都有着至关重要的影响。
Have you ever wondered what magical things are happening inside your body when you close your eyes, lie on your cozy bed, and drift into dreamland? You might think that sleeping is simply because we're tired and need to rest. But actually, sleep is far more than just "taking a break"! After decades of research, scientists have discovered that sleep is an extremely complex and vital life activity. It has a profound impact on our physical health, learning ability, emotional management, and even how long we live.
想象一下，如果你今年十岁，从出生到现在，你已经睡了大约五年的时间！如果你现在六十岁的爷爷奶奶，他们已经睡了将近二十年的觉！这就是我们要探讨的第一个重要发现：人类一生中大约有三分之一的时间都在睡眠中度过。这个数字听起来是不是很惊人？
Imagine this: if you are ten years old now, from the moment you were born until today, you have already spent about five years sleeping! If you have grandparents who are sixty years old, they have spent nearly twenty years sleeping! This is the first important discovery we're going to explore: humans spend approximately one-third of their lives sleeping. Doesn't that number sound amazing?
什么是睡眠？睡眠的科学定义
What is Sleep? The Scientific Definition of Sleep
在深入了解睡眠的重要性之前，让我们先来认识一下什么是睡眠。从科学的角度来看，睡眠（Sleep）是一种周期性的自然休息状态，在这个状态下，动物的意识会发生改变，大部分外界刺激不再引起反应。睡眠时，我们的身体会进行一系列重要的生理活动，包括组织修复、能量储存、记忆巩固等等。
Before we dive deeper into the importance of sleep, let's first understand what sleep actually is. From a scientific perspective, sleep is a periodic state of natural rest in which an organism's consciousness is altered, and most external stimuli no longer elicit responses. During sleep, our bodies carry out a series of important physiological activities, including tissue repair, energy storage, memory consolidation, and more.
人类的睡眠并不是一整块均匀的过程。科学家们通过脑电图（Electroencephalogram，简称EEG）等精密仪器的研究，发现睡眠主要分为两个截然不同的阶段：非快速眼动睡眠（Non-Rapid Eye Movement sleep，简称NREM睡眠）和快速眼动睡眠（Rapid Eye Movement sleep，简称REM睡眠）。这两个阶段会交替出现，形成一个完整的睡眠周期，每个周期大约持续90到110分钟。
Human sleep is not a uniform, continuous process. Through research using sophisticated instruments like the electroencephalogram (EEG), scientists have discovered that sleep is primarily divided into two distinct phases: Non-Rapid Eye Movement sleep (NREM sleep) and Rapid Eye Movement sleep (REM sleep). These two phases alternate throughout the night, forming complete sleep cycles, with each cycle lasting approximately 90 to 110 minutes.
非快速眼动睡眠又被细分为三个阶段：第一阶段是浅睡眠期，身体开始放松，呼吸和心跳变慢，脑波逐渐减慢；第二阶段是轻度睡眠期，身体更加放松，体温下降，脑波中出现特殊的"睡眠纺锤波"和"K复合波"；第三阶段是深度睡眠期，也被称为"慢波睡眠"，这时身体进入最深的休息状态，脑波变为缓慢的delta波，身体开始分泌生长激素，进行组织修复和能量恢复。
NREM sleep is further divided into three stages: Stage 1 is the light sleep phase, where the body begins to relax, breathing and heart rate slow down, and brain waves gradually become slower; Stage 2 is the light sleep phase, where the body becomes more relaxed, body temperature drops, and special "sleep spindles" and "K-complexes" appear in brain waves; Stage 3 is deep sleep, also called "slow-wave sleep," when the body enters its deepest state of rest, brain waves become slow delta waves, and the body begins to secrete growth hormone for tissue repair and energy restoration.
而快速眼动睡眠就是我们做梦的主要阶段。在这个阶段，你的眼球会快速转动，脑波变得活跃，类似于清醒时的状态，但身体的肌肉却处于瘫痪状态（这被认为是一种保护机制，防止我们在做梦时真的做出动作）。研究表明，REM睡眠对大脑的情绪调节和记忆整合起着关键作用。
REM sleep is the primary stage when we dream. During this phase, your eyes move rapidly beneath your eyelids, brain waves become active, similar to when you're awake, but your body muscles are in a state of paralysis (this is believed to be a protective mechanism to prevent us from actually acting out our dreams). Research shows that REM sleep plays a crucial role in emotional regulation and memory integration in the brain.
一个晚上，你会经历四到六个这样的完整睡眠周期。值得注意的是，前半夜的睡眠周期中，深度睡眠（NREM第三阶段）占的比例较大；而后半夜的睡眠周期中，REM睡眠的时间则更长。这就不难解释为什么很多小朋友在早上醒来前会做比较生动的梦了！
During one night, you will experience four to six of these complete sleep cycles. It's worth noting that in the first half of the night, deep sleep (NREM Stage 3) accounts for a larger proportion, while in the second half of the night, REM sleep lasts longer. This explains why many children tend to have more vivid dreams just before waking up in the morning!
三分之一的生命：睡眠的时间账本
One-Third of Life: The Time Account of Sleep
让我们更具体地算一算睡眠时间的这笔账。如果你今年八岁，按照每天需要十到十一个小时睡眠计算，到今天为止，你已经：
Let's calculate the sleep time account more specifically. If you are eight years old now, and you need ten to eleven hours of sleep per day, by today, you have:
- 睡眠了大约3到4年的时间
- Slept approximately 3 to 4 years
- 做了超过10万个梦
- Had over 100,000 dreams
- 经历了超过10万次睡眠周期
- Experienced over 100,000 sleep cycles
- 在睡眠中"长高"了一点点（睡眠时身体会分泌生长激素）
- Grown a little taller during sleep (the body secretes growth hormone during sleep)
如果你现在十八岁成年了，这些数字会变成：睡眠超过6年，做梦超过20万次，经历超过20万次睡眠周期。到了六十岁的时候，你将在睡眠中度过将近二十年的时光！
If you are now 18 years old and have become an adult, these numbers would change to: over 6 years of sleep, over 200,000 dreams, and over 200,000 sleep cycles. By the time you reach sixty years old, you will have spent nearly twenty years of your life sleeping!
这样的计算让我们意识到，睡眠绝不是浪费时间。相反，它是我们生命中最重要的"投资"之一。睡眠就像是大自然为我们安排的一项神秘任务，而我们每个人都是这个任务的主角。
These calculations help us realize that sleep is definitely not a waste of time. On the contrary, it is one of the most important "investments" in our lives. Sleep is like a mysterious task arranged by nature for us, and each of us is the protagonist of this task.
不同年龄的睡眠需求：你需要睡多久？
Sleep Needs at Different Ages: How Long Should You Sleep?
了解了睡眠的重要性之后，你可能会问：那我到底需要睡多久才够呢？这是一个非常好的问题！不同年龄段的人，需要的睡眠时间是不同的。科学家们根据大量的研究数据，为各个年龄段的人们制定了推荐的睡眠时间指南。
Now that we understand the importance of sleep, you might ask: how long do I actually need to sleep? This is an excellent question! People of different ages have different sleep requirements. Based on extensive research data, scientists have developed recommended sleep duration guidelines for people of all ages.
美国国家睡眠基金会（National Sleep Foundation）发布的最新睡眠建议如下：
The latest sleep recommendations published by the National Sleep Foundation are as follows:
| 年龄段 | 建议睡眠时间 | 备注 | |--------|-------------|------| | 新生儿（0-3个月） | 14-17小时 | 刚出生的宝宝需要最多的睡眠 | | 婴儿（4-11个月） | 12-15小时 | 睡眠逐渐变得规律 | | 幼儿（1-2岁） | 11-14小时 | 包括午睡时间 | | 学龄前儿童（3-5岁） | 10-13小时 | 午睡逐渐减少 | | 学龄儿童（6-13岁） | 9-11小时 | 避免睡眠不足 | | 青少年（14-17岁） | 8-10小时 | 青少年需要较多睡眠 | | 青年人（18-25岁） | 7-9小时 | | | 成年人（26-64岁） | 7-9小时 | | | 老年人（65岁以上） | 7-8小时 | 睡眠可能变浅 |
| Age Group | Recommended Sleep Duration | Notes | |-----------|---------------------------|-------| | Newborns (0-3 months) | 14-17 hours | Newborns need the most sleep | | Infants (4-11 months) | 12-15 hours | Sleep gradually becomes regular | | Toddlers (1-2 years) | 11-14 hours | Includes nap time | | Preschoolers (3-5 years) | 10-13 hours | Naps gradually decrease | | School-age children (6-13 years) | 9-11 hours | Avoid sleep deprivation | | Teenagers (14-17 years) | 8-10 hours | Teenagers need more sleep | | Young adults (18-25 years) | 7-9 hours | | | Adults (26-64 years) | 7-9 hours | | | Older adults (65+ years) | 7-8 hours | Sleep may become lighter |
作为小学生（6-13岁），你每天需要大约9到11个小时的睡眠。这意味着如果你早上七点起床，晚上应该在八点到十点之间上床睡觉。你达标了吗？
As a school-age child (6-13 years old), you need approximately 9 to 11 hours of sleep each day. This means if you wake up at seven in the morning, you should go to bed between eight and ten o'clock at night. Are you meeting this standard?
有意思的是，随着年龄的增长，我们需要的睡眠时间反而在减少。这主要是因为老年人的深度睡眠时间减少，而且他们的睡眠效率（实际睡着的时间与躺在床上的总时间的比值）也下降了。但这并不意味着老年人不需要睡眠，只是他们的睡眠模式发生了变化。
Interestingly, as we age, the amount of sleep we need actually decreases. This is mainly because older adults spend less time in deep sleep, and their sleep efficiency (the ratio of actual sleep time to total time spent in bed) also decreases. However, this doesn't mean older adults don't need sleep; it just means their sleep patterns change.