Sleep health data

Sleep duration, sleep rhythm, frequency of waking at night, and other indicators such as deep sleep ratio and REM sleep duration vary greatly among individuals, and the monitoring error of consumer equipment is high, so it is not recommended to be used as a general health evaluation standard.

Hey, to be honest, there are a lot of people who come to me recently to complain about sleep data anxiety. Last week, my cousin came to me with a screenshot of a smart watch, frowning that her deep sleep accounted for only 16%, which was 10 percentage points lower than the "health standard" given by APP. Is there something wrong with her body? In order to make up this percentage, she lay flat one hour in advance for a week, listening to white noise and soaking hot feet. Instead, she couldn't sleep until one or two o'clock, and she was so sleepy that she couldn't lift her head when she went to work during the day.

Let's talk about the most basic sleep time. Many people open their mouths and say that "adults should sleep for 8 hours". In fact, this is only a general reference value, and it is not an iron law at all. I compiled the sleep reference values of all ages released by the American Sleep Medical Association in 2015 into a table, which you can compare, but you don't need the dead card values:

|--------------|--------------|

Remarks: This data is a general reference, and individuals can fluctuate for 1-2 hours due to differences in genes and living habits, as long as it does not affect daytime function.

Don't believe that some people are born with little sleep. In 2009, the research team at the University of California, San Francisco found that people with DEC2 gene mutation can fully recover their energy by sleeping for 4-6 hours every day, and there will be no health damage. The proportion of such people in the crowd is about 1%-3%. Maybe the colleague around you who sleeps for 5 hours every day is a natural "short sleeper", so there is no need to envy others.

Oh, by the way, what is more important than the length of sleep is actually the sleep rhythm. I have a friend who works as an independent designer for three years. She sleeps from 2 o'clock to 10 o'clock every day, and her physical examination is normal every year. She is much more energetic than when she forced herself to get up at 7 o'clock before going to work. In fact, there is no unified conclusion about the optimal solution of rhythm: the traditional view is that "going to bed early and getting up early" with the rise and fall of the sun is more in line with the law of human hormone secretion and more friendly to long-term health; However, in recent years, the study of chronobiology has also pointed out that everyone's circadian rhythm is different. Some people are born as "night owls" (delayed sleep phase). Forcing themselves to go to bed early will cause sleep fragmentation. As long as the work and rest are fixed and the cycle is stable, no matter whether they go to bed early or get up late, they will have little impact on health. The "staying up late" that really hurts the body is actually sleeping at 10 o'clock today and sleeping at 2 o'clock tomorrow, and the work and rest are completely disorderly.

There is also a core indicator that many people have not noticed: the frequency of awakening at night. That is, when you wake up at night, you may have no impression at all, and then turn over and fall asleep. The house I rented before was a barbecue stall downstairs, and there was always noise in the middle of the night. The bracelet showed that I woke up unconsciously 3-4 times a night, lasting 5-10 minutes each time, and I didn't feel anything at all, but even if I slept for 9 hours, I still had to drink two cups of coffee in the afternoon to hold on. Later, I changed the silent window, and the frequency of awakening dropped to only 1-2 times a week. Generally speaking, waking up unconsciously for more than 2 times and more than 5 minutes every night will affect the quality of sleep in the long run, even if you feel that you have "slept enough".

As for the proportion of deep sleep and REM sleep that everyone is anxious about every day, there is really no need to take it too seriously. First of all, it must be made clear that these data of consumer-grade bracelet watches are estimated by heart rate and motion sensors, which are only 60%-75% consistent with the clinical gold standard polysomnography (PSG, which requires EEG, EMG sensors to be accurate), and the maximum error can reach 30%, so it has no clinical reference value at all. Moreover, the individual differences of such indicators are particularly large: people who often do strength training need more deep sleep for muscle repair, and the proportion will naturally be higher; It is normal for people who do creative work every day and need to deal with a lot of information to have a high proportion of REM sleep in charge of memory integration, and there is no unified "health standard line" at all.

At present, the industry is divided into two groups for this kind of non-core data: most doctors in the clinical school suggest that ordinary people simply don't look at these indicators. They have slept well, but they are anxious when they see the wrong values. The more anxious they are, the more they can't sleep, but they fall into a vicious circle; Practitioners of digital health believe that these data can be used as a reference for personal long-term trends. For example, the proportion of deep sleep has been stable at around 20% before, and it has suddenly dropped to 10% recently. The high probability is that there is too much pressure or too little exercise recently, and it can be adjusted accordingly without completely denying the value of the data.

My own method of using sleep data is particularly rough: I never open the APP every day to see the proportion of deep sleep, but I can pull the weekly report at most once a week and see three points: did more than 80% of the days fall asleep at the same time this week, did I get enough sleep for 7.5 hours that I am used to, and did I wake up less than twice at night? As long as these three are up to standard, I will turn my head and forget.

Say a thousand words and ten thousand words, sleep data is essentially a reference tool, just like your white blood cells are slightly higher when you have a physical examination, maybe you just caught a cold recently, and there is no need to stare at the values every day to take supplements. After all, the most accurate "gold standard" is whether you can work comfortably the next day after sleeping, and you don't have to rely on coffee to lift your spirits. You can't make yourself insomnia in order to make up a few percentages on the APP, right?