The best time to sleep has been revealed. Do you sleep during this time period?

The best time to sleep has been revealed. Do you sleep during this time period?

The inner workings of a modern night owl:

"I have to work overtime tonight. Looks like I'll have to stay up late or pull an all-nighter again!"

"It's already midnight, but only the night time belongs to me. I really don't want to sleep!"

iiMedia Research survey data shows that 98.5% of respondents have stayed up late in the past six months, of which 67.2% stayed up late on their own initiative; 43.4% of respondents said they stayed up late 1-3 times a week. Moreover, 80.9% of consumers with insomnia are aged 22-40, which shows that the problem of office workers staying up late is quite serious. Some people even stay up until 2 or 3 in the middle of the night and have to get up at 6 or 7 in the morning to go to work, which means they don’t get enough sleep.

Staying up late has many harmful effects on the body. It not only makes us mentally exhausted, but also causes a series of health problems. In this article, we will list the harms of staying up late and the best sleep time mentioned in the study, and finally give reasonable suggestions for those who have to stay up late.

Research shows that these are the dangers of staying up late!

The importance of sleep to physical health is self-evident, and there are naturally many studies on the harm of staying up late to the body.

- Promote aging: A study published in the Journal of Neuroscience mentioned that staying up late and not getting enough sleep can lead to sleep disorders, which affect the human brain in many ways. If you are completely deprived of sleep, that is, you don’t sleep all night, your brain will instantly age 1 to 2 years the next day. [1] However, this damage is reversible. As long as you get enough sleep afterwards, you can reverse this abnormality by making up for it in time.

- Easy to gain weight: Sleep time is correlated with obesity. Sleep plays an important role in hormone secretion, metabolic changes, etc. Staying up late or lack of sleep will cause corresponding adverse effects, which will lead to weight changes.

In addition, lack of sleep can lead to increased levels of ghrelin and decreased levels of leptin in the blood, which can increase subjective hunger by stimulating appetite, making people tend to choose high-energy foods and less likely to choose fresh fruits and vegetables. The fatigue caused by lack of sleep can also cause people to reduce exercise and increase sedentary time.

Studies have shown that sleeping too short or too long can significantly increase weight and the risk of obesity. In an analysis of the association between sleep duration and weight gain of more than 5 kg, the risk was 26% higher in the short sleep group and 12% higher in the long sleep group compared with normal sleep. In an analysis of the association between sleep duration and the risk of obesity, the short sleep group had a 35% higher risk of obesity, but the association between long sleep and obesity was not significant. [2]

It can be seen from this that lack of sleep will really make you gain weight. If you want to maintain your body shape or lose weight better, getting a good night's sleep is also an important prerequisite.

- Increased risk of type 2 diabetes: Several studies have shown that sleep duration and sleep quality can lead to decreased insulin sensitivity and glucose tolerance. Short sleep duration or poor sleep quality can lead to decreased insulin sensitivity and glucose tolerance, thereby increasing the risk of type 2 diabetes. [3]

A cross-sectional survey of sleep duration among 15,145 Chinese adults aged 18 to 75 years showed that those who slept less than 6 hours had significantly impaired fasting blood sugar levels compared to those who slept 6 to 8 hours. [4]

- Increased risk of hypertension: Insufficient sleep not only increases the risk of diabetes, but also has a significant impact on blood pressure. Many elderly people with hypertension will feel that if they do not sleep well at night, their blood pressure will increase the next day. Many studies have confirmed that insufficient sleep increases the incidence of hypertension in the population, [3] and also increases the risk of other cardiovascular-related diseases.

- Susceptibility to Alzheimer's disease: Every time you stay up late, you may be one step closer to Alzheimer's disease. Animal studies have found that staying up late or not getting enough sleep can lead to the deposition of beta-amyloid protein in the brain, which is one of the important signs of Alzheimer's disease. The increase in beta-amyloid protein plaques increases the risk of developing Alzheimer's disease. [5]

- Prone to myocardial infarction: Many friends who have experience of staying up late may have had this experience. Occasionally, they will feel a tightening and twitching pain in their heart. You must be careful.

A study published in the Journal of the American College of Cardiology from Renji Hospital affiliated to Shanghai Jiao Tong University School of Medicine found that staying up late increases the risk of myocardial infarction. For patients who have already had a myocardial infarction, staying up late will significantly increase the area of ​​the myocardial infarction, which is about 20% higher than that of those who do not stay up late, and will lead to a significant increase in major adverse cardiac events by 92%. [6]

- Impact on immune function: Night owls who stay up late for a long time often have malnutrition in their diet and lack of exercise, which naturally has a negative impact on maintaining immunity. At the same time, studies have also confirmed that staying up late will reduce immunity.

Studies have shown that long-term lack of sleep can have a lasting adverse effect on hematopoietic stem cells, which in turn affects the normal function of the lymphatic system, affects immune function, and increases the body’s inflammatory response. [7] Getting enough sleep of 7 to 8 hours a day can help prevent inflammation and disease, especially for people who already have underlying diseases.

- May cause cancer: As early as 2007, the World Health Organization (WHO) has defined staying up late as a Class 2A carcinogenic factor. Although staying up late is not 100% certain to cause cancer, it will increase the risk of cancer.

In addition, staying up late will also make your memory worse, your skin worse, your eyes dry, your mood low, and you irritable...

What time is the best time to go to bed?

There is a lot of controversy about what time to go to bed. Some people think that the earlier the better, while others think that as long as you get 7 to 8 hours of sleep, it doesn't matter what time you go to bed.

Stop arguing, the best time to sleep is out.

A cohort study involving 88,026 British participants explored the relationship between bedtime and cardiovascular disease risk and ultimately identified the optimal sleep time. The study showed that the time of bedtime and cardiovascular disease risk showed a "U"-shaped relationship, and going to bed too early or too late would increase the risk of cardiovascular disease. [8]

Going to bed before 22:00 at night increases the risk of cardiovascular disease by 24%. Going to bed between 22:00 and 23:00 can reduce the risk of cardiovascular disease. Going to bed between 23:00 and 00:00 increases the risk of cardiovascular disease by 12%. Going to bed after 00:00 or later increases the risk of cardiovascular disease by 25%. [8]

Another large cohort study involving more than 320,000 adult participants showed that when sleep duration reached 7 hours per day, mortality from all causes, cardiovascular disease, and other causes was reduced to the lowest level. [9]

Therefore, based on the above two studies, it is recommended that you should fall asleep between 22:00-23:00 and ensure 7 hours of sleep.

What to do if you have to stay up late?

We know that staying up late is harmful to health, but sometimes we have to work overtime, be on duty, study, and stay up late for life. In this case, how can we reduce the harm of staying up late to the body?

-Before staying up late: Find an opportunity to take a short nap before staying up late to ensure that you have more energy at night; staying up late will consume more B vitamins, so pay attention to its supplementation in your diet, such as increasing the intake of whole grains, or you can directly take complex B vitamin supplements; don’t eat too much at dinner to avoid drowsiness after meals and affect your work at night. You can add low-calorie foods to your meals, such as milk oatmeal, cucumbers, and cherry tomatoes.

- Staying up late: Do not drink coffee frequently just to stay up late, to avoid having difficulty falling asleep after work, or even affecting the quality of sleep and getting up frequently at night; get up and walk around regularly to reduce sitting and avoid drowsiness; the lighting should be appropriate, not too dim or not turned on, otherwise it will damage your eyesight; use artificial tears properly to moisturize your eyes.

-After staying up late: Make sure to replenish water the next day. Men and women should drink at least 1700 ml and 1500 ml respectively; eat more dark vegetables to replenish rich carotene to protect the eyes; and get enough sleep. Although getting enough sleep cannot completely eliminate the damage caused by staying up late, it can help us restore our physical strength and condition and reduce the damage.

Staying up late may feel good, but the harm should not be underestimated. Some friends stay up later and later. Night owls, cherish your life! Don't stay up late for revenge!

References:

[1]Chu, Congying et al. “Total Sleep Deprivation Increases Brain Age Prediction Reversibly in Multisite Samples of Young Healthy Adults.” The Journal of neuroscience : the official journal of the Society for Neuroscience vol. 43,12 (2023): 2168-2177. doi:10.1523/JNEUROSCI.0790-22.2023

[2]. Zhang Shuang, Li Lian, Huang Yubei, Chen Kexin. Meta-analysis of sleep duration in adults on weight gain and obesity risk[J]. Chinese Journal of Epidemiology, 2015(36):519-525.

[3] Yang Tingting, Anne F. Fish, Kong Weimin, et al. Research progress on the correlation between insufficient sleep and cardiovascular metabolic diseases[J]. Chongqing Medicine, 2017, 46(24): 3430-3433.

[4]Lou, Peian et al. "Interaction of sleep quality and sleep duration on impaired fasting glucose: a population-based cross-sectional survey in China." BMJ open vol. 4,3 e004436. 13 Mar. 2014, doi:10.1136/bmjopen-2013-004436

[5]Parhizkar, Samira et al. “Sleep deprivation exacerbates microglial reactivity and Aβ deposition in a TREM2-dependent manner in mice.” Science translational medicine vol. 15,693 (2023): eade6285. doi:10.1126/scitranslmed.ade6285

[6]Zhao, Yichao et al. "Disruption of Circadian Rhythms by Shift Work Exacerbates Reperfusion Injury in Myocardial Infarction." Journal of the American College of Cardiology vol. 79,21 (2022): 2097-2115. doi:10.1016/j.jacc.2022.03.370

[7]McAlpine CS, Kiss MG, Zuraikat FM, et al. Sleep exerts lasting effects on hematopoietic stem cell function and diversity. J Exp Med. 2022; doi: 10.1084/jem.20220081external link

[8] Shahram Nikbakhtian, Angus B Reed, Bernard Dillon Obika, Davide Morelli, Adam C Cunningham, Mert Aral, David Plans, Accelerometer-derive sleep onset timing and cardiovascular disease incidence: a UK Biobank cohort study, European Heart Journal - Digital Health, 2021;, ztab088, https://doi.org/10.1093/ehjdh/ztab088

[9]Svensson T, Saito E, Svensson AK, et al. Association of Sleep Duration With All- and Major-Cause Mortality Among Adults in Japan, China, Singapore, and Korea. JAMA Netw Open. 2021;4(9):e2122837. doi:10.1001/jamanetworkopen.2021.22837

Author: Xue Qingxin, registered dietitian

Reviewer: Zhang Yu, researcher at Chinese Center for Disease Control and Prevention

The article is produced by Science Popularization China-Creation Cultivation Program. Please indicate the source when reprinting.