我们为何需要8小时睡眠？

Why do we need eight hours of sleep?

常速 | 四级（偏易） | 809词 | 3min37s

刘立军供稿

Part I. QUESTIONS

Listen to the passage and choose the best answer to each question you hear.

Q1. What does Dr. Sanjay Gupta say about the commonly recommended eight hours of sleep?

A. It is the minimum amount required for all adults.

B. It is mainly suitable for teenagers and children.

C. It represents an average rather than a fixed standard.

D. It has recently been proven to be scientifically inaccurate.

Q2. Which stage of sleep occupies the largest proportion of an adult’s sleep cycle?

A. Stage one sleep.

B. Stage two sleep.

C. Stage three sleep.

D. REM sleep.

Q3. Why does Dr. Gupta consider sleep especially important for students?

A. It improves physical strength and athletic performance.

B. It reduces the amount of study time students need.

C. It helps transfer daily experiences into long-term memory.

D. It allows the brain to remain active throughout the night.

Q4. What can be inferred about irregular sleeping habits?

A. They mainly affect people who travel frequently.

B. They may interfere with the body’s natural rhythm.

C. They can quickly increase the total amount of sleep.

D. They are less harmful than excessive screen use.

Q5. What is the main purpose of the conversation?

A. To compare the sleeping habits of adults and children.

B. To warn people about the long-term dangers of technology addiction.

C. To discuss the relationship between exercise and brain development.

D. To explain the functions of sleep and ways to improve sleep quality.

Part II. TRANSCRIPT

Why do we need eight hours of sleep?

I got 5 hours of sleep last night. Last night, this is not normal. I got about 6 and 1/2 hours of sleep. Last night, I slept four hours. I got 5 hours 45 minutes of sleep. Last night, I got about 5 hours of sleep. Usually, I try to shoot for 7 to 8.

It seems like most people are not getting 8 hours of sleep. We got a wide range of answers today. I am on a mission to find out if that’s really what we need to do. And I’m bringing in a special guest, Dr. Sanjay Gupta.

How are you? You missed this discussion. Oh man, you are the man I need to speak to. So why eight hours? Is this the optimal amount?

optimal adj. 最佳的，最适宜的

(Q1) So you know, like most things in life, it’s an average. The average is a range between 6 and 10 hours for most adults. The thing is, for kids, it’s actually even more than that—9 to 12 hours for elementary school kids and teenagers, back to sort of 8 to 10 hours.

(Q5-1) Take us inside of our brains. What happens while we sleep?

Sleep is actually a really fascinating time for the brain. It’s kind of interesting because people think it’s just at rest. It’s actually really active. And there are several stages of sleep. (Q2) Stage one, you spend about 5% of your time in stage one. That’s the lightest sleep, just sort of drifting off to sleep. Then stage two, a little bit deeper. About 45% of your sleep is stage two. Then there’s stage three, which is the most restful, about 25%. And then there’s this really interesting stage. It’s called REM—rapid eye movements. Literally, your eyes are moving behind your eyelids, and that’s when you’re dreamy. Yeah. And you cycle over and over again through these stages of sleep. About 90 minutes or so for all the stages.

The other thing your brain is doing is clearing out waste from all the work that it’s done during the day. (Q3) And I think most importantly for students, that’s the time you take memories and experiences from your day and you put them in the long-term memory stores so you can remember these months, years down the road.

So how do I know if I’ve gotten enough sleep for me, for my body?

So, most people generally know because you are probably a little bit grumpier than you normally are. You’re always cheery though, aren’t you? I’ve never seen you grumpy. You know, you feel tired. I think one of the biggest tests—someone told me this years ago—is if you put yourself in a darkened room in a comfortable chair and right away you fall asleep within a couple of minutes; that’s a pretty sure sign that you’re sleep-deprived.

grumpy adj. 脾气坏的，易怒的

(Q5-2) So, give your boy some tips and all of us on getting great sleep.

So, you’re an athlete, probably working out too close to when you go to bed; it’s probably going to keep you up. You’re sort of stimulating the body. Caffeine stimulates the body. So, in the morning, good idea. But later on in the afternoon, that’s probably going to keep you up. Screens, the blue light alone is something that’s going to keep you up. It just kind of wakes your brain up. Kind of wakes your brain up. Yeah. It’s like, hey, time to wake up. Time to actually do something.

caffeine n. 咖啡因

I think the biggest thing is the idea of sleeping around the same time and waking up at the same time every day. It’s like you’re confusing your brain. (Q4) If you go to bed 2 hours early or 2 hours later, your brain’s like, “Wait a second. Is it time to sleep or is it not time to sleep? I’m not sure.” If you get into a consistent pattern of whatever time, so let’s say 11 to 7, uh, every day, you’re likely to get good sleep. Your brain’s not confused, and you can stick with that pattern.

Is that connected to that circadian rhythm we always have?

circadian adj. 生理节律的

And your circadian rhythm can get sort of messed up very quickly. You see that when you travel to LA or, you know, any kind of jet lag? You can essentially put yourself into jet lag right at home by confusing your brain like that all the time if you do nothing else. Well, get rid of the screens for sure, but after that, go to bed at the same time, wake up at the same time.

You know my tip for great sleep? Hang out with people who just put you at ease. And for me, you’re one of those people. You’re the best sleep. You’re the best.

I’m not sure. It’s good that I put you to sleep.

Part III. KEY

Q1. C.【解析】细节题。题目出处为：“So you know, like most things in life, it’s an average. The average is a range between 6 and 10 hours for most adults.” 意为：“就像生活中的很多事情一样，八小时只是一个平均值。对于大多数成年人来说，平均睡眠时间范围是6到10小时。”该句表明“八小时睡眠”并非绝对标准，而是一个平均参考值，因此正确答案为C。

Q2. B.【解析】细节题。题目出处为：“Then stage two, a little bit deeper. About 45% of your sleep is stage two.” 意为：“第二阶段睡眠更深一些，大约占全部睡眠时间的45%。”结合前文“Stage one, you spend about 5% of your time in stage one”以及后文“Then there’s stage three, which is the most restful, about 25%”可知，第二阶段占比最高，因此正确答案为B。

Q3. C.【解析】细节题。题目出处为：“And I think most importantly for students, that’s the time you take memories and experiences from your day, and you put them in the long-term memory stores so you can remember these months, years down the road.” 意为：“我认为，对学生来说最重要的是，睡眠期间你的大脑会把白天的记忆和经历储存到长期记忆中，以便未来数月甚至数年后仍能记住。”该句直接说明了睡眠对学生的重要意义，因此正确答案为C。

Q4. B.【解析】推理题。题目出处为：“If you go to bed 2 hours early or 2 hours later and your brain’s like, ‘Wait a second. Is it time to sleep or is it not time to sleep? I’m not sure.’” 意为：“如果你提前两小时或推迟两小时睡觉，你的大脑就会想：‘等等，现在是该睡觉的时候，还是不该睡？我也不确定’。”由此可以推断，不规律的睡眠习惯会扰乱人体自然生物节律，因此正确答案为B。

Q5. D.【解析】主旨题。题目出处为：“Take us inside of our brains. What happens while we sleep?”以及“… give your boy some tips and all of us on getting great sleep.” 主持人请Gupta博士解释睡眠期间大脑的活动并提供改善睡眠的建议，随后他们对睡眠阶段、大脑功能、记忆形成以及健康睡眠习惯进行了详细讨论，因此正确答案为D。

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