Is it true to get 8 hours of sleep a night to be healthy?
What time at night is the best place to sleep? 10 o'clock? 11 o'clock? 12 o'clock?
How long is the best time to take a nap? 20 minutes? 30 minutes? Or 1 hour?
Image source: Stand Cool Helo
These questions may seem simple, but you may not be able to answer them correctly.
Because sleep is one of the most difficult biological mysteries for humans to explain.
The latest published scientific research results have answered 4 sleep problems that we care about!
Today, Brother Dian will take you to understand.
If you want to understand these studies in detail, read the whole text carefully; if you just want to read the conclusions, just look down at the bold text!
How long you get enough sleep each day actually varies from person to person. Like what:
Elementary school students aged 10 to 13 must sleep at least 9 hours a night;
Adults over the age of 20 usually only need 7 to 8 hours per night [1].
The so-called "8 hours of sleep" is just a very rough average. There is no need to be demanding that you must sleep for 8 hours.
The criterion for judging whether you have enough sleep time is whether you have enough energy during the day and are not easy to fall asleep.
In September 2021, a study published in the Journal of the American Medical Association (JAMA) gave the answer to this question [2].
The study, from the National Cancer Center in Japan, analyzed the relationship between sleep duration and risk of death in East Asian populations.
A total of 320,000 people took part in the study, including Chinese.
The average age of the participants was 54 years, with women accounting for 55%.
Based on the length of sleep each day, participants were divided into 6 groups:
5 hours or less, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours or more.
The results found:
Among women, the most slept 7 hours a day (33.8%);
Among men, those who slept the most 8 hours a day (35.1%).
The most important findings were that the lowest points of all-cause mortality, cardiovascular disease and other causes of mortality, both men and women, fell on 7 hours of sleep.
In a nutshell: People who sleep 7 hours a day have the lowest risk of death for all causes; while sleeping too little (less than 5 hours) or too much (more than 10 hours) increases the risk of death.
Therefore, Dian Ge would like to remind you that if the sleep time is too short or too long, the risk of some specific diseases will increase. This may be because[2]:
Sleep is short, and secretion of a hormone called "leptin" decreases, while the secretion of auxin-releasing peptide increases. Changes in these two hormones can make people have a good appetite, and eating more increases the risk of obesity and diabetes, which in turn increases the risk of cardiovascular-related death.
The long sleep time may be because certain diseases have been hidden in the body, but they have not yet been diagnosed. At this time, the disease may lead to the release of inflammatory substances, such as C-reactive protein, which are all related to increased sleep time.
In November 2021, a study specifically analyzed the relationship between the timing of falling asleep and the risk of heart disease [3].
Researchers from institutions such as Oxford University in the United Kingdom, 88,000 people (on average 61 years old, 58% of women) were selected to collect their time to fall asleep and wake up. Then, over an average period of 5.7 years, they were followed up on their newly diagnosed cardiovascular disease.
The results showed that people who fell asleep at 12 a.m. (or later) had the highest incidence of cardiovascular disease; the lowest were those who fell asleep at 10 to 11 p.m.
Specifically, compared with people who fall asleep every night from 10 to 11 p.m.:
People who fell asleep at 12 a.m. (or later) had a 25% increased risk of cardiovascular disease;
People who fall asleep at 11 to 12 p.m. have a 12% increased risk of cardiovascular disease;
People who fell asleep before 10 p.m. had a 12 percent higher risk of cardiovascular disease. (Wouldn't it be okay to go to bed too early?) And let no one live! ）
Of course, going to bed early is better than staying up late. Because staying up late also increases the risk of cancer!
Poke the video to see the downsides of staying up late
There's also the bad news – the food you eat for dinner may also affect your cardiovascular disease risk.
In May 2021, a study by Harbin Medical University showed:
Eating too many refined carbohydrates and high-fat meats for dinner is at higher risk of heart disease. For example, processed meats (such as bacon, burgers, chicken nuggets, etc.) and foods with added sugar (such as cakes, breads, sweet drinks, etc.) [4].
Eating high-quality carbohydrates and plant protein for dinner can reduce the risk of cardiovascular disease by about 10%. For example, vegetables, soy products, natural grains (such as brown rice, pure oatmeal porridge, etc.).
To help you summarize:
If you want to reduce the risk of cardiovascular disease, it is best to go to bed at 10 to 11 o'clock every night. (It is to close your eyes and fall asleep, not to say that you go to bed and cover the small quilt to continue to play with your mobile phone Oh ~)
Also, it is recommended to eat a light snack for dinner. Cakes, braised pork, fried chicken and other delicacies should be enjoyed at noon.
Seeing this, someone will definitely raise their hand and ask: How to sleep during napping?
The answer is: sleep lying down.
No kidding you. We workers rarely have the conditions to lie down and sleep at noon, most of them lie on their desks and take a nap. You must have had the experience of falling asleep on your stomach, drooling with numbness in your hands and feet, and getting more tired.
In fact, the actual significance of the nap is to relieve fatigue and make the afternoon work more energetic (convenient for the boss to work better). If you have the conditions, you can buy a camp bed and sleep as much as possible, which is more comfortable and more relieving.
As for how long to nap, studies suggest that either limit it to less than 20 minutes or sleep well for the entire full sleep cycle (90 minutes) – if you have enough time.
Why? Because people fall asleep for 20 to 30 minutes, they will fall into a deep sleep. When you wake up at this point, you will feel very tired, which is not conducive to getting into a working state quickly.[5]
The experts have something to say
Li Zhong
Director and Chief Physician of the Department of Neurology, Sixth Affiliated Hospital of Sun Yat-sen University
In fact, there is no need to force you to sleep between 10 and 11 o'clock every day. Occasionally, short-term, for a special reason, going to bed a little earlier or later, is not a big problem.
It's important to plan when you sleep at night or nap, and keep your mouth shut so you get better quality sleep and a healthy body.
Don't forget to share this article with your circle of friends
Get a good night's sleep with your beloved friends
bibliography
[1]https://www.sleepfoundation.org/how-sleep-works/how-much-sleep-do-we-really-need.
[2] Svensson, T., Saito, E., Svensson, A. K., et al. (2021). Association of sleep duration with all-and major-cause mortality among adults in Japan, China, Singapore, and Korea. JAMA network open, 4(9), e2122837-e2122837.
[3] Nikbakhtian, S., Reed, A. B., Obika, B. D., et al, D. Accelerometer-Derived Sleep Onset Timing and Cardiovascular Disease Incidence: A UK Biobank Cohort Study. Available at SSRN 3857637.
[4] Hou, W., Gao, J., Jiang, W., et al. (2021). Meal Timing of Subtypes of Macronutrients Consumption With Cardiovascular Diseases: NHANES, 2003 to 2016. The Journal of Clinical Endocrinology & Metabolism, 106(7), e2480-e2490.
[5]https://www.sleepfoundation.org/how-sleep-works/stages-of-sleep.
Author: Zhuang Shilihe
Editors: Zhang Jie, Emgrand, Zhang Liang
Proofreading: Wu Yihe | Typesetting: Li Yongmin
Operation: Han Ningning | Coordinator: Wu Wei
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