The scientific basis for sleep-related information
Myths about Sleep Quality
Given the pace of modern life, it has become difficult for people to take the time to get a good night's sleep. It can seem like a dream to be able to get a good night's sleep every day. But as we all know, sleep is as important to our health as diet and exercise, and good sleep can improve our brain performance, mood and health.
If you don't get enough quality sleep on a regular basis, you are at a higher risk for many diseases and disorders, from heart disease and stroke to obesity and dementia.
The Meaning of Sleep
Dr. Maiken Nedergaard, who studies sleep at the University of Rochester, believes that sleep is simply "downtime" for a tired brain to rest, and since it's a time for the brain to prepare to learn, remember and create, "it's not just resting. He says.
Dr. Nedergaard and her colleagues found that the brain has a system for removing toxins during sleep, and during sleep the brain changes its normal function and works like a kidney to remove waste products, she explained.
The team found in mice that this system removed some of the proteins associated with Alzheimer's disease, and these toxins were removed from the brain twice as fast during sleep. Dr. Kenneth Wright, Jr. a sleep researcher at the University of Colorado, explains that everything from blood vessels to the immune system uses sleep as a time for repair. There are certain repair processes that occur in the body most effectively during sleep, and if you don't get enough sleep, these processes are disrupted, says Dr. Junior.
Lies about Sleep
The amount of sleep needed depends on the age of the child, but experts recommend that children need at least nine hours of sleep a day and teens need eight to ten hours.
As for adults, they need at least seven hours of sleep.
One of the myths is that adults need less sleep as they get older, but even if you are an elderly person, you still need the same amount of sleep as an adult, but the quality of your sleep may worsen as you age, and some people are on medication that interferes with their sleep. Another myth is that it's okay to sleep in on holidays, but studies have shown that this is almost never true. While it may make sense to take a nap or sleep longer the next night if the quality of sleep the night before was poor, sleeping longer on Sundays to make up for a week's worth of sleep deprivation is not considered healthy behavior.
Recent studies have shown that sleep deprivation causes weight gain and worsens the physiological functions that control blood sugar levels.
On the other hand, more sleep is not always better, and if an adult is getting more than 9 hours of sleep and not feeling refreshed, there may be an underlying medical problem.
Sleep drives metabolite clearance from the adult brain. Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O'Donnell J, Christensen DJ, Nicholson C, Iliff JJ, Takano T, Deane R, Nedergaard M. Science. 2013 Oct 18; 342(6156):373-7. doi: 10.1126/science.1241224. PMID: 24136970.
Ad libitum weekend recovery sleep fails to prevent metabolic dysregulation during a repeating pattern of insufficient sleep and weekend recovery sleep . depner CM, Melanson EL, Eckel RH, Snell-Bergeon JK, Perreault L, Bergman BC, Higgins JA, Guerin MK, Stothard ER, Morton SJ, Wright KP Jr. Curr Biol. 2019 Feb 11. pii: S0960-9822(19)30098-3. doi: 10.1016/j.cub.2019.01.069. PMID:30827911.
Decline in academic performance
Poor sleep quality can have a negative impact on a student's academic performance. Since average sleep duration, quantity and quality of sleep are strongly associated with students' learning ability, poor academic performance and poor interpersonal relationships that predispose to mental disorders, this study aimed to assess the magnitude and correlation of sleep quality among medical students in Ethiopia.
An institution-based cross-sectional study was conducted on
576 undergraduate medical students and data was collected using an interviewer administered questionnaire and sleep quality was assessed using Pittsburgh Sleep Quality Index (PSQI). The collected data was entered into Epi-data version 3.1, analyzed using SPSS version 20, and logistic regression was used to identify potential determinants of sleep quality in undergraduate medical students.
P-values less than 0.05 were considered statistically significant, and the strength of the association was indicated by adjusted odds ratios with 95% CIs.
Results.
The prevalence of poor sleep quality among medical students was found to be 62%. The mean age of the respondents was 21.5 years, and 53.8% were male.
Depression (AOR = 1.92, 95% CI 1.16,3.19)
Lack of social support (AOR = 5.39,95%CI 2.33,2.49)
Stress (AOR = 2.04, 95% CI 1.26,3.31)
Poor sleep hygiene (AOR = 3.01,95%CI 1.75,5.18)
and it was also found to be associated with poor sleep quality with a p-value < 0.05.
The results of the study showed that an increase of one unit in grade point average was associated with an 81.5% decrease in poor sleep quality (AOR = 0.185, 95% CI 0.13, 0.28).
Wondie, T., Molla, A., Mulat, H. et al. Magnitude and correlates of sleep quality among undergraduate medical students in Ethiopia: a cross - sectional study. Sleep Science Practice 5, 7 (2021). Available at: https://doi.org/10.1186/s41606-021-00058-2
Blood sugar levels
People with diabetes have high levels of blood glucose (or blood sugar), and high blood glucose levels can have a variety of detrimental effects.
According to one study.
African-Americans with sleep disorders are associated with higher blood sugar levels. Previous studies have also found these signs in European and Asian populations.
The researchers looked at data from about 800 African-American men and women who underwent home sleep apnea testing. The subjects wore a device that measured whether they were awake or asleep for a week and were asked to keep a sleep diary. The researchers looked at how long the subjects slept, how often they woke up in the middle of the night, and changes in their sleep patterns, and compared them to blood glucose levels taken at the clinic.
The results.
They also found that about a third of the participants had sleep apnea and most were not receiving treatment for it.
Those with sleep apnea and disturbed sleep patterns were found to have higher blood glucose levels, and those with the most severe sleep apnea had blood glucose levels 14% higher than those without sleep apnea.
Most people with sleep apnea have no symptoms.
Many people with sleep apnea have no symptoms. Dr. Yuichiro Yano of Duke University, who led the study, explained that the results of this study reaffirm the need for improved screening and diagnosis of sleep apnea, both in African Americans and other groups.
Sleep Characteristics and Measures of Glucose Metabolism in Blacks: The Jackson Heart Study. Yano Y, Gao Y, Johnson DA, Carnethon M, Correa A, Mittleman MA, Sims M, Mostofsky E, Wilson JG, Redline S. J Am Heart Assoc. 2020 May 5;9(9):e013209. doi: 10.1161/JAHA.119.013209. Epub 2020 Apr 28. PMID: 32342760.
Sleep quality and fruit and vegetable intake.
This is the first study to demonstrate the expected association between sleep duration and fruit and vegetable consumption.
Cross-sectional, prospective data have been
obtained from a cohort study of women in the UK, where sleep duration was assessed by self-report of average sleep duration on weekdays and weekends, and diet was assessed by a 4-day food diary at baseline and follow-up (approximately 4 years later).
Sleep duration was categorized as short (≤6 h/d), recommended (7-9 h/d), and long (≥9 h/d), and a restricted cubic spline model was developed to investigate potential nonlinear associations between sleep duration and fruit and vegetable intake, using regression analysis adjusting for age, socioeconomic status, smoking, ethnicity, and total energy intake.
Results.
In an adjusted cross-sectional analysis, we found that
People with short sleep duration averaged 17 g/d (95% CI -30 to -4, p = 0.01)
Those with longer sleep duration averaged 25 g/d (95% CI -39 to -12, p < 0.001).
and the total amount of fruits and vegetables was low compared to the recommended RS. An adjusted prospective analysis also found that those who slept less had a lower intake of fruits and vegetables, on average 85 g/d, compared to the RS. In a restricted cubic spline model, the cross-sectional and expected associations between sleep duration and fruit and vegetable intake were non-linear, with women who slept 7-9 hours/day having the highest fruit and vegetable intake.
And the dietary tendencies of those who slept too little or too much also included a significantly higher tendency to over-calorie and snack on snacks, a result that suggested that BMI levels were also related to time.
In Japan, it is recommended to eat 350 grams of vegetables and 200 grams of fruit a day, but the people who slept for the recommended amount of time in this study did not meet those requirements.
However, other factors may affect the amount of time we sleep, so we should only know this as an indicator.
Noorwali, E.A., Hardie, L.J. & Cade, J.E. Recommended sleep duration is associated with higher consumption of fruits and vegetables; cross-sectional and prospective analyses from the UK Women and prospective analyses from the UK Women's Cohort Study. Sleep Science Practice 2, 13 (2018). Available at: https://doi.org/10.1186/s41606-018-0032-0
Sleep Disorders and the Workplace
When it comes to sleep disorders, we want to avoid them as much as possible because they affect not only our work performance but also our health.
Here are some conclusions from a social science paper that gives some hints on the subject.
The study
The study was conducted in Korea.
28,804 people over the age of 15 who worked three or more days a week were surveyed. Questionnaires were conducted on the size of the company they worked for, the number of employees, the shift system, commuting time, etc.
The correlation between these and sleep disorders was investigated.
Conclusion
Various factors suggested a correlation between commuting time and sleep disorders.
When commuting time exceeds 60 minutes, sleep time tends to decrease.
There was also a study in the U.S. that showed that people who spent more than three hours a day commuting to work were more likely to have health problems.
When broken down by gender, men and women who commute more than 50 minutes and 40 minutes, respectively, are more likely to have sleep disorders. This is also the result. Long working hours were also considered a problem, but commuting time had more to do with it.
https://doi.org/10.1016/j.shaw.2019.08.001
Advantages and disadvantages of napping
There is a tendency for people who do not get satisfactory sleep at night to take naps. The environment in which they live makes it difficult for them to get a good night's sleep.
I think there will be people who need to take a nap.
In 2009, a study by Cote concluded that
Napping has been shown to improve performance in areas such as reaction time, logical reasoning, and symbol recognition, as well as improve mood throughout the day. A study by Jennifer at the University of Michigan in 2015 showed that a 60-minute nap can strengthen tolerance due to frustration and increase tolerance to cravings.
All of this points to an emotional reset as a benefit of mastering what we have learned. And in terms of learning alone, it seems that a 90-minute nap may be equivalent to 8 hours of sleep in reinforcing what has been learned.
In addition, a 2008 study by MedNic found that a 90-minute nap and 8 hours of sleep had the same effect on learning, and in an experiment with an afternoon latte compared to a placebo, the early memory scores of those who napped and those who did not napped were better.
This suggests that the effects of napping may be similar to the physiological effects of caffeine. So far, these are the benefits of napping, but there are some drawbacks that can occur if napping becomes too excessive.
One is that it is associated with systemic inflammation.
It has been suggested that increased levels of C protein, which is associated with systemic inflammation, is due to excessive sleep and napping.
On the other hand, we do know that taking naps can help restore immune function. On the other hand, we know that napping restores immune function, but excessive sleep does not provide this benefit.
And the downside is that napping may simply interfere with your nighttime sleep.
Apparently, we should use the 90 minutes that studies have shown as a guideline.
Although naps are not biologically mandatory, it is possible that people who take regular naps perform better in the evening than those who do not.
Of course, this is not necessary if you are getting a good night's sleep and have no performance problems.
However, if you have problems with sleep deprivation and performance, you may want to consider taking a nap as an option.
Studies have validated napping for 60~90 minutes, so I think it's okay to try napping when it suits your schedule.
Mednick, S., Ehrman, E. (2006). Take a nap! Change your life. New York, NY: Workman Publishing.
Milner, CE, & Cote, KA (2009). Benefits of napping in healthy adults: effects of nap length, time, age, and nap experience. Journal of Sleep Research, 18, 272-281. doi: 10.1111 / j.1365-2869.2008.00718.x
Studte, S., Bridger, E., and Mecklinger, A. (2015). Napping preserves associativity, but not item memory performance. Neurobiology of Learning and Memory, 120, 84-93. doi: 10.1016 / j.nlm.2015.02.012
Changes in the sense of taste
What I hear about taste is that there is a change in the perception of sweetness and saltiness with age. It's a bit of anecdotal evidence, but I've always wondered if such a thing could happen. I was wondering if it could happen.
There is a study that suggests that there may be a relationship between taste and sleep quality. I would like to introduce you to a study that shows that there may be a relationship between taste and sleep quality.
Contents of the study
The purpose of the study was to evaluate taste sensitivity and sleep patterns through age. Thirty-five adult males and 24 elderly subjects were studied for sleep assessment (Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale) and taste sensitivity.
Taste sensitivity was assessed using three dilutions, which showed different concentrations for the four basic flavors (salty, sweet, bitter, and sour).
These samples were encoded with three digits and presented randomly to the participants in 50 mL plastic cups.
As a result, the quality of sleep was poor in both groups.
Older adults showed adverse effects in identifying sweet and salty tastes, and in this population, sleep duration was found to be associated with perception of sweetness.
Discussion
The study showed that older adults have difficulty discriminating between sweet and salty tastes, independent of sleep quality.
According to this researcher, a change in the duration of the intervention may change the conclusions, since there is no change in taste perception after less than 7 hours of sleep per night. It is true that a decrease in the quality of sleep may affect the sense of taste, as it may decrease biological sensitivity. It seems to be a sensory experience.
Although the results are limited, there is some data showing that taste sensitivity decreases with less sleep. It can be inferred from this that when the body is tired, it tends to want to eat sweets, so we cannot say with certainty, but there may be a relationship.
Martelli ME, Jacob N, Morais MA, et al. Taste sensitivity throughout age and the relationship with sleep quality. Sleep Sci. 2020;13(1):32-36. doi: 10.5935/1984-0063.20190127
Checking the quality of sleep.
When your sleep becomes unsatisfactory, you want to do something about it because it will affect your daily life.
One way to do this is to keep a record of how long you sleep, but do you know how long it is useful to keep a record? Here is a study that investigates the number of days to record.
Contents of the study
Recording sleep is important for epidemiological studies of disorders and diseases that may be related to sleep deprivation and limitation.
The purpose of the current study was to test how many days and weeks are needed to apply a reliable sleep diary. The study was conducted with 53 male and female participants. Volunteers completed a morning and evening questionnaire to later identify their chronotype.
Afterwards, they received a sleep diary in which they filled in periods of 28 consecutive days (or 4 weeks) of nocturnal sleep.
Participants were instructed to describe the time they began to fall asleep and woke up within one hour of waking.
As a result,
there was no difference in the amount of time participants slept from week to week. Participants slept longer on Sundays and Saturdays compared to other days of the week.
The reliability value of the sleep diary increased as the number of nights increased, reaching adequate reliability (≥0.70) recorded for seven consecutive days.
Borba DA, Reis RS, Lima PHTM, et al. How many days are needed for a reliable assessment by the Sleep Diary? Sleep Sci. 2020;13(1):49-53. doi:10.5935/1984-0063.20190131
Physical health of people working day and night shifts.
Excerpted content from a conversation with Dr. Kenneth Wright Jr, an NIH-funded sleep expert at the University of Colorado at Boulder.
What is the Circadian System?
The circadian system is the internal clock provided by the human body. It controls the timing of many of our activities, such as when we eat and when we are active.
As an example, there is a hormone called melatonin, and the body clock determines when melatonin is produced, but since melatonin is a hormone related to sleep, when melatonin levels are high, appetite does not occur. Therefore, if you do not get enough sleep, you will wake up when melatonin levels are high, and if you eat during this time, your blood sugar levels will tend to be low.
Disruption of the body clock
Long-term disruption of the body clock can lead to weight gain, obesity, and may even lead to the onset or worsening of depression. It can also lead to type 2 diabetes, heart disease and stroke, and the onset of symptoms from cancer.
One of the factors that contribute to this disruption of the body clock is "shift work," a topic that has been called into question because this way of working goes against basic biology.
People who work in shifts should try to maximize their total sleep time in a 24-hour period as a countermeasure against the disruption of the body clock. This is done by going home after the night shift, staying awake for a little while and then going to sleep. At that time, you can sleep for 5-6 hours, but most of the time, your body clock will wake you up. This is because our body clocks are programmed to wake us up, not because we have had enough sleep.
Therefore, if you wake up after 5-6 hours of sleep, give yourself about 2 hours before you go to work to take a nap. This will give you the recommended 7 to 8 hours of sleep.
However, people who start work early in the morning, say before 7 a.m., often have insomnia because they have to go to bed earlier than usual. To cope with insomnia, these people may take melatonin, try to go to bed earlier, or use light to adjust their body clock.
Waking up at the same time every day is also important for shift workers. If you work irregular hours, your body clock will be disrupted, which can lead to many health problems.
From NIH News helth:Dr. Kenneth Wright on Shift Work and Sleep
