Sleep Health Research

The core conclusion about sleep health is very clear - there is no universal "standard sleep template", and the core indicators to judge whether sleep is healthy are never rigid requirements such as "sleeping enough for 8 hours" and "going to bed before 10 o'clock", but the two core criteria of "long-term rhythm stability" + "no persistent feeling of fatigue after waking up".

I followed the team from the Sleep Laboratory of the Municipal Mental Health Center for more than half a year of community follow-up last year, and met too many people who were deceived by stereotyped sleep standards. The one who impressed me most was a 95-year-old girl who worked on the Internet. In order to comply with the "healthy schedule" mentioned on the Internet, she forced herself to change her previous habit of going to bed at 12 a.m. and waking up at 8 a.m. to lying down at 10 a.m. and getting up at 6 a.m. As a result, she lay in bed for more than two hours every day before she could fall asleep. In less than three months, she lost one-third of her hair volume due to persistent anxiety. When she went to the laboratory for monitoring, her sleep efficiency had only reached 60%. Later, we asked her to change her sleep schedule back to her original schedule. We only asked her to have a difference of no more than half an hour between falling asleep and waking up every day, regardless of the specific time. After two months, we visited again. Her sleep efficiency increased to 92%, and her overall condition was visibly improved.

In fact, the academic debate on sleep rhythm has been going on for almost 20 years, and there have always been two voices with solid evidence. The traditional rhythm school insists that the human body's melatonin secretion and cortisol fluctuations follow the rise and fall of the sun. Going to bed late for a long time is equivalent to forcibly disrupting the body's built-in clock that has evolved over millions of years. Even if you sleep for enough hours, the long-term risk of metabolic diseases and cardiovascular diseases will be more than 30% higher; and recently The individual rhythmists who have emerged in recent years have come up with the opposite cohort study data: people themselves are divided into lark type, owl type and intermediate type. As long as they can keep their schedule stable for a long time, even if they go to bed at 2 am and start at 10 noon, as long as the sleep cycle is complete, there will be no statistical difference in health risks from those who go to bed early. In 2023, "Sleep Medicine Reviews" published a meta-analysis covering 210,000 samples, and the final compromise conclusion was: Regardless of whether you go to bed early or late, people who have a long-term stable sleep schedule have a 37% lower risk of suffering from various chronic diseases than people who have a sleep schedule that alternates between morning and evening, and sleep duration that changes from long to short. To put it bluntly, "not messing with the rhythm" is much more important than "pursuing a standard schedule."

Another mistake that many people tend to make now is to regard sleep data from consumer devices as imperial edict. I have done controlled tests in the laboratory before. For sleep monitoring of the same volunteer on the same day, the deep sleep duration measured by the medical polysomnography instrument was 1 hour and 47 minutes, while the data given by the three mainstream consumer bracelets were 42 minutes, 2 hours and 13 minutes, and 1 hour and 12 minutes respectively. The error can be up to 40%. To put it bluntly, the data analysis logic of this type of device relies on body movement and heart rate estimation, and it is impossible to accurately judge sleep stages. To judge whether you have slept enough, you have to look at two feelings: whether you can get up smoothly within 10 minutes after waking up, and whether you will feel sleepy regardless of the occasion during normal work and study during the day. These two indicators are more reliable than any APP's sleep score.

As for how to treat insomnia, which everyone is most concerned about, there is no absolutely unified answer in the industry. Current mainstream guidelines regard cognitive behavioral therapy (CBT-I) as the first-line intervention for insomnia. It is believed that it can fundamentally correct misperceptions about sleep without drug side effects. However, many clinicians have suggested that for sudden acute insomnia (such as encountering a major accident or being unable to sleep for more than a week due to jet lag), appropriate short-term use of non-benzodiazepine sleep aids is more effective and can prevent short-term insomnia from turning into chronic insomnia. There is no need to talk about sleep aids as if they are facing an enemy. Those legendary sleep-aid methods, such as foot soaking, listening to white noise, and spraying sleep-aiding essential oils, essentially help you establish a conditioned reflex for sleep. If you are still watching exciting short videos while soaking your feet every day, no matter how hot the water is, it will not help you. There are also people who rely on drinking alcohol to help them sleep. I advise you to stop as soon as possible. Alcohol can indeed make you fall asleep quickly, but it will greatly suppress the duration of REM sleep. It looks like you are sleeping deeply, but in fact, your sleep in the second half of the night is fragmented, and you will only be more tired when you wake up.

The longer I do this, the more interesting I find sleep. It is the most instinctive need of the body. The more you focus on it and force it to meet standards, the more likely it is to cause problems. An old professor who has studied sleep for a lifetime told me that the best sleep regimen is not to take sleep seriously, go to sleep when you feel sleepy, and get up when you wake up. It is more effective than any expensive pillows or sleep aid supplements. This sounds a bit rough, but if you look carefully, it is really the case.