I really want to ask: How long is the best amount of sleep per day?

"How long is the best sleep for a person?" This question can be said to be the most frequently asked question in the topic of sleep. Many people have heard the saying "it is best for a person to sleep X hours a day" on the Internet or other channels, and then they feel anxious or blame themselves for not meeting this standard, and then fall into a cycle that makes them particularly entangled: the more they want to sleep X hours, the less they sleep. So, how long is the best sleep for a person? Is there an answer to this question?

Let me first give the answer: It depends on the person.

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Different ages require different amounts of sleep per day

In order to answer the question of "how much sleep do people need", the American Academy of Sleep Medicine once organized a sleep expert group. The group members reviewed hundreds of high-quality studies on sleep time and health issues, and then after several rounds of voting and discussion, they finally set a range for the sleep time required for different age groups.

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In general, infants and young children need the most sleep. As they age, the amount of sleep they need tends to decrease until they are 18 years old, when the change gradually stabilizes. Note that it is stabilizing, not fixed. Therefore, sleep needs can vary at different ages. You may have noticed why there are no recommendations for babies under 3 months old. The reason is that the sleep needs of this age group vary greatly [1] (from 11 hours to 19 hours). So, mothers, please be careful not to compete with other children in the community for sleep time and then come back to disturb your baby.

Do adults need to sleep more than 7 hours a day?

Let me first give the answer: it is still the same, it varies from person to person. But most adults do need more than 7 hours of sleep a day, and the majority here is a statistical "average".

If you are usually in a bad state most of the time during the day, often feel sleepy, or need to rely on coffee to stay alive, and then calculate whether you have slept for 7 hours at night, the problem you need to consider at this time is: insufficient sleep at night. The next step is to readjust your work and rest schedule and let yourself sleep more.

But please note that neither "most people" nor "average" equals the standard answer. In the sleep time statistics chart, in addition to the 7 hours in the middle, some data are distributed at both ends. The far left is "short sleepers" and the far right is "long sleepers."

In this world, there are some people who don't need to sleep that much. Sleeping for 6 or 5 hours is enough. The so-called "enough" means that it does not affect the daytime state. They don't need to take a nap or coffee during the day. They can work just like other ordinary people. Such people are called "short sleepers".

Note that short sleepers are not trained, but born short sleepers. Research has found that this is related to certain gene mutations[2]. In terms of numbers, there are very few people with this "gift", no more than 1%, and if estimated, only about 3%[3].

In contrast to short sleepers, some people are born with a need to sleep for a long time. For example, they often need to sleep for 9 or even 10 hours to ensure their energy level during the day (for adults). These people are called “long sleepers” [4]. In many cases, the pattern of long sleepers starts in childhood and continues into adulthood.

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Similar to short sleepers, long sleepers are also very rare, only about 2% [5]. Moreover, some research shows that they are also related to genetics. Obviously, compared with short sleepers, long sleepers are very hard-working. Because whether in school or at work, the outside world does not allow them to "willfully" sleep as much as they need, so long sleepers are the group of people who are most likely to "not get enough sleep". They often doze off during the day, affecting their learning and work efficiency. But if it is during holidays, as long as they sleep as much as their bodies need, their performance will return to a very good state.

Anyway, from short sleepers, to the middle "7-9 hours average", to "long sleepers", these sleep data form a normal continuous "time spectrum". The so-called "adults need 8 hours of sleep" is just a reference answer. As an individual, you cannot label yourself as "not enough sleep" or "too much sleep" based on a single number. In other words, how much sleep you need can be different from others. Combined with what I said before, I can now summarize 2 sentences: Don't compare your sleep time with the past. Don't compare your sleep time with others.

How to judge how much sleep you need every day? Simply put: look at your performance after waking up. If you can stay awake enough most of the time after waking up, and can maintain good enough concentration, and it does not affect your work and life, then you can think that you have slept well. On the contrary, if you are easily sleepy after waking up and your concentration decreases, then it means that you did not sleep well enough - either the time is not enough, or the quality is poor, or both.

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At this time, you can refer to the "average" of adults - 7 hours. If the time is less than 7 hours, you can try to find out "where the time has gone". If the time is 7 hours, then you need to find out if there are other "sleep resistances" that are interfering with your sleep quality.

If you want to get more specific, you can refer to the “checklist of questions” provided by the National Sleep Foundation [6]:

① Does 7 hours of sleep make you feel productive and healthy? Or do you notice that you need more sleep to function better during the day?

② According to your current work and rest schedule, do you often feel sleepy during your daily work?

③ Do you rely on caffeine to get through the day?

④ Do you tend to sleep more on holidays when you don’t need to work?

By answering the above 4 questions, you will have a rough idea of ​​whether your current sleep time is enough.

What should I do if I don’t get enough sleep? After completing the above “question list”, an outpatient suspected that he might be a “long sleeper”. His results were as follows:

① 7 hours of sleep cannot provide a good state during the day.

② Often feel sleepy.

③ Just drink 3 cups of coffee a day.

④ During holidays, he often sleeps for 10 hours. He doesn’t need to drink coffee during the day and is in very good condition. So, for him, it is to let himself sleep as much as possible without delaying work in the morning. How to do it? You can refer to the following 3 steps:

1. Draw a pie

The "pie" here refers to reviewing your "time spending", just like doing household financial expenditures, sorting out the activities before going to bed at night, and calculating how much time each of them takes up.

Secondly, sort out the less important projects and try to delete them or reduce their time. Of course, you don’t have to be like an ascetic every night, you can change a little bit each time.

2. Ceremony

Develop a relaxing bedtime ritual. For example, take a bath, watch your phone, play games, etc., and then stay away from the screen for about half an hour before bedtime. The benefit of doing this is that it can make it easier for the brain to get rid of the intense daytime work and Internet information, which is conducive to falling asleep.

3. Get some sleep

There are always various things that deprive you and me of sleep at night. If you really don’t get enough sleep at night, you can take a nap to make up for it.

However, making up for sleep requires some skills. You can't make up too much at one time, otherwise, it will easily affect your sleep that night and disrupt your overall sleep rhythm.

The most recommended way to make up for sleep is to use four words: installment payment. For example, if you don’t get enough sleep on weekday nights, take a 20-minute nap during the noon period. On holidays, sleep a little longer in the morning, no more than 1 hour after waking up on weekdays, and take another 20-minute nap at noon. If you are tired at night, go to bed early.

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Summarize:

① Most adults need about 7 hours of sleep, but this is not the standard answer. As an individual, you cannot measure whether you sleep well based solely on this number.

② Whether you get enough sleep depends on your daytime state after waking up. If you don’t get enough sleep, check whether you get 7 hours of sleep as most people do. If not, it indicates that other factors are depriving you of sleep. If you get enough sleep, you need to find out if there are other sleep obstacles that are affecting your sleep quality.

③ If you plan to sleep more, you can take three steps: drawing cakes, rituals, and catching up on sleep. In short, the adult world is not easy. No one can sleep well every day for 365 days. Don’t worry about short-term lack of sleep. Just treat it as a Buddhist.

There are many interesting things worth doing in life, not just to have a good night's sleep.

References

[1]Kirsch, D. (2022, September 12). Stages and architecture of normal sleep. In SM Harding (Ed.). UpToDate., Retrieved March 1, 2023, from

[2] American Life Science Network: Does sleep deprivation syndrome really exist?

[3] Sleep Education Website: “Short Sleep” Gene: When Six Hours Is Enough

[4]Patel, SR, Blackwell, T., Ancoli-Israel, S., Stone, KL, & Osteoporotic Fractures in Men-MrOS Research Group (2012). Sleep characteristics of self-reported long sleepers. Sleep, 35(5), 641–648.

[5]American Academy of Sleep Medicine.(2014).The International Classification of Sleep Disorders–Third Edition (ICSD-3). Darien, IL.

[6] For a Better You, Better Sleep Website: How Much Sleep Do You Need?

Author: Yu Zhouwei, attending physician of neurology, author of "Sleep Formula"

Reviewer: Tang Qin, Director and Researcher of the Science Popularization Department of the Chinese Medical Association