The importance of sleep health

The core value of sleep health is never simply "rest", but the underlying physiological foundation that supports human immunity, cognition, metabolism and even emotional stability. The health risks of long-term sleep disorders are much higher than the high-oil and high-sugar diet that most people are wary of every day.

Last week, I helped an old Internet operator adjust his work schedule. He had been working on projects for three consecutive months and slept less than five hours a day on average. Taking advantage of his good health at the age of 27, he drank ice cream when he felt sleepy. He drank two cans in a row to stay up until the middle of the night. He felt that "sleeping less is just yawning during the day, it's no big deal." As a result, during a routine physical examination at the unit last week, his fasting blood sugar was found to be 6.3mmol/L, which is the critical line of abnormal glucose tolerance. The first sentence of the endocrinology doctor after reading the report was not to tell him to give up milk tea or fried chicken, but to ask him to ensure that he sleeps 6.5 hours a day for a month, and then come back for a review.

Many people's understanding of sleep is still at the level of "you only need to supplement when you are tired". They think that as long as they suppress their sleepiness with coffee and energy drinks, it will not affect the body's function. A controlled experiment published in "Nature Neuroscience" last year has already exposed this illusion: subjects who slept less than 6 hours for three consecutive days had an average decrease in activity of the brain's prefrontal cortex by 23%, and the corresponding decrease in reaction ability and judgment accuracy was almost the same as when the blood alcohol concentration reached 0.05%. To put it bluntly, you think your thinking is clear and fine, but in fact the probability of driving and making mistakes has doubled, but you just can't notice it.

At this point, someone will definitely ask, how long is enough sleep to be considered healthy? In fact, there is currently no unified standard answer to this question in the academic community. The mainstream school is the standard promoted by the American Academy of Sleep Medicine for more than ten years: adults aged 18-64 should sleep 7-9 hours a day, and less than 6 hours is considered insufficient sleep. However, in recent years, more and more individualized research schools have put forward a completely different view: the reference significance of sleep duration is far lower than sleep quality and personal feelings. As long as you are fully awake within 10 minutes after waking up and can maintain stable energy during the day without relying on coffee or strong tea, then even if you only sleep for 6 hours a day, you are still a completely normal "short sleeper". There is no need to force yourself to lie down for 8 hours. On the contrary, it is easy to cause anxiety due to being unable to sleep, and induce real insomnia.

I just met a parent of a senior in high school last month, and I fell into this trap. She read on the Internet that "high school students not sleeping enough for eight hours will affect their performance in exams." She insisted that the children go to bed at 10 o'clock every day. As a result, the children were already under great pressure to study and could not fall asleep while lying in bed with their minds full of knowledge points. After lying there for half a month, they developed conditioned insomnia. They became nervous when they touched the pillow, and in the end they could only sleep for more than three hours a day. Later, when we made adjustments, we first removed all the requirements of "8 hours of sleep" and let him follow his own pace. Even if he goes to bed at 12 o'clock and wakes up at 5:30 every day, as long as he sleeps for more than 85% of the time in bed, it will be no problem. His sleep state has completely returned to normal in about half a month.

Oh, by the way, many people catch colds every time the season changes, and the wounds on their skin heal slowly. Their first reaction is "My immunity is low, I need to take some vitamin supplements." But if you look at your daily schedule in the past half month, you will most likely stay up late and suffer from lack of sleep. An experimental data from the Stanford University Sleep Laboratory in 2021 shows that people who sleep less than 4 hours a day for a week will have a 37% decrease in the activity of NK cells that fight viruses and remove mutated cells. This decrease is much greater than if you were exposed to the cold wind for half an hour and ate junk food for 3 days in a row.

I have been doing sleep intervention for 6 years, and the most common misunderstanding I have seen is that people always regard sleep as "redundant time that can be sacrificed at any time": squeeze in sleep time first to catch up on projects, squeeze in sleep time before binge watching TV series, squeeze in sleep time first when preparing for exams, always thinking that you can make up for it by catching up on a long sleep when you are done. In fact, if you think about it, your body is like a 24-hour community convenience store. It is open during the day to pick up customers. The store is closed at night not to give the clerk a rest, but to take inventory of the day's inventory, clean the store, and replenish the goods to be sold the next day. If you open the door two hours earlier and close the door two hours later every day, all the time will be taken away from inventory and replenishment. In less than half a month, the store will definitely be in a mess: there are not the goods that should be there, the food that is due has not been cleared, the floor is full of garbage, and all kinds of problems will arise. Sleep is the time for closing the shop and taking inventory. Every hour of sleep you sacrifice is essentially setting up trouble for the normal functioning of the body.

And to be honest, the damage caused by lack of sleep cannot be made up by supplementary sleep. Those who stay up until early morning on weekdays and sleep for 12 hours at a stretch on weekends must have experienced this: after waking up, they feel groggy and even more tired than when they go to work. This is because catching up on sleep can only relieve superficial fatigue. The metabolic damage and cognitive loss caused by the loss of deep sleep cannot be repaired by fragmented catching up on sleep. On the contrary, it will disrupt your original circadian rhythm and make you more tired.

Of course, you don’t need to be overly anxious after reading it. Staying up late or staying up all night once in a while will not cause any irreversible damage to the body. You don’t need to read the post that “staying up late for a long time can cause cancer” will scare you so much that you lie in bed and turn over and over, unable to fall asleep. Instead, you will suffer from anxiety insomnia. Our bodies are much more durable than you think. As long as we can maintain a relatively regular schedule most of the time, have enough energy when we are awake, and are not so tired that we can't open our eyes at every turn, that's enough. After all, whether you sleep well or not, your own body feelings are more honest than all academic standards.