The dangers of staying up late are well known to everyone: poor energy, sluggishness, memory loss, reduced immunity, and even premature aging.
So the sooner you go to bed, the better?
Not.
In a recent large study published in November 2021 by the European Heart Journal Digital Health, a journal of the European Society of Cardiology (ESC), a team of researchers from oxford university in the United Kingdom and others found the best "time to fall asleep" to prevent cardiovascular disease.
Moreover, going to bed early, or sleeping too late, is a health risk...
Found the "best time to fall asleep"?
Participants were aged 37–73 and had an average age of 61. The researchers followed them up to identify newly diagnosed cases of cardiovascular disease. Cardiovascular disease is defined as myocardial infarction, heart failure, chronic ischemic heart disease, stroke, and transient ischemic attacks.
The researchers found that after correcting for a confounding factor such as age, sex, length of sleep (both short and long sleep durations are associated with a higher risk of cardiovascular disease), body mass index, diabetes, blood pressure, etc., the sleep start time showed a "U" relationship with cardiovascular risk: people from 22:00 to 22:59 had the lowest risk of cardiovascular disease, went to bed too early and too late increased the risk of disease, and fell asleep in the early morning (24:00) and later at midnight or later. (This time refers to local time, not Beijing time.) ）
The European study is the most extensive study to date of objectively assessed relationship between sleep and cardiovascular disease risk.
A clear link between "sleep time" and cardiovascular disease risk was demonstrated, especially for women.
The optimal "time to fall asleep" is within a specific range of the daily cycle, and deviating from this range, whether too early or too late, can be problematic.
Which is the greater harm, late sleep or lack of sleep?
Previous studies by the University of California have shown that sleeping a lot and sleeping very little can cause health hazards.
The truth of the answer may be the biological clock, and violating the laws of the biological clock will cause harm to physical health. Irregular schedules can affect the resetting of the "biological clock".
All life on Earth has a physiological mechanism called the biological clock (2017 Nobel Prize in Physiology and Medicine).
Inside each of us is the biological clock, a 24-hour cycle from day to night, an invisible clock, a cycle of light and darkness that coincides with the rotation of the earth.
The circadian clock is governed by the "superior optic nucleus" of the hypothalamus of the brain, and both wakefulness and eating behavior are attributed to the role of the circadian clock, which is the inner rhythm of the life activities of the organism and contributes to the regulation of the body's physical and mental function.
If you do not follow the rhythm of the biological clock to arrange your schedule, the human body will feel tired and uncomfortable. In the long run, it will have a great negative impact on people's physical and mental health.
The most typical example is the well-known inverted jet lag, medical "jet lag syndrome" long-distance flight across multiple time zones fatigue patients due to circadian rhythm disorder, will appear insomnia at night and sleepy during the day, dizziness and bloating, severe headaches, palpitations, nausea, as well as judgment and attention loss.
Of course, in fact, some people naturally prefer to go to bed early, while others prefer to sleep late, and each body has a unique internal timer to adjust. At present, the scientific understanding of sleep and the biological clock is far from enough, and it is necessary to further explore the mysteries.
How to maintain the body clock?
So, how to maintain the body's biological clock and maintain physical and mental health?
1. Time to fall asleep
Fall asleep before 23:00. Don't stay up too early, use the time originally used to stay up late for sleep, and fight for the part of the time you go to bed late to get up early.
2. Proper sleep time
People's sleep needs are different. The consumption of energy is not the same as the sleep time is not the same. The quality of sleep is not the same as the length of sleep time.
A person's sleep time varies with age:
Newborns need to sleep 16-20 hours a day
Adolescents and children are 9-10 hours, with a minimum of eight and a half hours
The need for sleep in adults is further reduced, and it only takes 7-8 hours
The sleep time of the elderly is only 5-6 hours
3. Sleep regularity
It is best to set a time every day, follow the rise and fall of the sun, "sunrise and work, sunrise and breathing" to follow the operation of the biological clock, do not randomly disrupt it.
Sleep is largely a habit, so maintain good sleep habits and follow the natural laws of sleep.
4. For people who regularly fly across time zones, pay attention to time difference.
This article is reviewed by Xue Shimin, deputy chief physician of the Department of Respiratory Medicine, Yulin Second Hospital