“Good sleep” is full of benefits!
What are the points to improve the quality of sleep?

Sleep can rest not only the body but also the brain.

We carry out various physical and mental activities while we are awake, and “fatigue” accumulates accordingly. If fatigue accumulates, the “desire to sleep” sent from the brain becomes stronger, which leads to sleep.
Sleep consists of two types of sleep that differ qualitatively; i.e., “REM sleep” and “non-REM sleep” REM sleep is a shallow sleep, in which the body is resting, but preparing for awakening because you dream or the blood pressure and pulse fluctuate. On the other hand, non-REM sleep is a state, in which the brain wave activity is decreased and the brain (mind) is resting due to deep sleep.
It is generally said that brain (mental) fatigue recovers during non-REM sleep and body fatigue recovers during both types of sleep, especially during REM sleep. Sleeping is an important part of rest for the tired brain.

Not only the amount of time, but also the quality are important for sleep.

It is considered that sleeping more than 6 hours but less than 8 hours is a standard for Japanese adults. However, the time that they can actually sleep (amount of sleep per night) is about 7, 6.5, and 6 hours at the age of 25, 45, and 65 years, respectively, showing a decrease by about 30 minutes with aging. In addition, the amount of sleep time tends to be shorter in the summer season and longer in the winter season.
In this way, the sleep time varies depending on age, season, individual differences, etc., and in the modern society where it may not be possible to secure the time as expected, “quality of sleep” becomes important.

So, what kind of sleep can be said as “high-quality sleep”? The evaluation criteria for sleep quality provided by the Ministry of Health, Labour and Welfare show as follows.
・A regular rhythm of sleep and wakefulness is maintained, showing a clear difference between day and night.
・The required time of sleep is secured, and there is no sleepiness or falling asleep during the day, living in a good mental and physical condition.
・It is seldom to be awakened during the course, having stable sleep.
・It is possible to wake up comfortably and clearly in the morning.
・It is possible to act smoothly after waking up.
・It is possible to fall asleep without excessive time after getting into bed.
・Sleep gives a feeling of deep sleep.
・Satisfaction can be obtained without excessive fatigue during the day.

Recovery from fatigue

The actions of internal organs, function to regulate body temperature, etc. performed in the body are controlled by the autonomic nervous system which continues to work for 24 hours regardless of our will. The autonomic nervous system includes the sympathetic nervous system and parasympathetic nervous system. The sympathetic nervous system is involved in tension, and the parasympathetic nervous system is involved in relaxation. Both systems maintain health while being balanced.
If tired, the functions decrease in both nervous systems, but dysfunction of the parasympathetic nervous system is particularly severe, making the sympathetic nervous system dominant. In other words, a tensed state becomes stronger.
Then, the brain releases an SOS signal that is “sleepiness” to rest the body. If you sleep following this signal, the balance of both systems is restored. However, if you continue the activity, suppressing the sleepiness, the dysfunction of the parasympathetic nervous system cannot be resolved, resulting in a chronic fatigue state. In addition, brain blood flow decreases, thereby impairing the ability to concentrate and judge.
The most effective way to avoid these conditions is sleep. Good quality sleep enhances the function of the parasympathetic nervous system, and balancing with the sympathetic nervous system leads to recovery of fatigue.

Resolving stress

Sleep has an action to resolve mental fatigue. In addition, recovery of brain fatigue can be expected, and therefore concentration, memory, and thinking abilities as cognitive functions are maintained/adjusted, leading to resolution of stress.
Also, it has been shown that insufficient sleep increases the secretion of cortisol, a stress hormone, but conversely, good quality sleep may lead to suppression of the secretion of the stress hormone.

Prevention of obesity

Sleep and obesity are closely related. It has been found that shorter sleep time decreases the secretion of a hormone called leptin, which suppresses appetite, and increases the secretion of a hormone called ghrelin, which promotes appetite. It is also reported that the consumption of high-carbohydrate snacks has increased by 30%. Namely, short sleep can disrupt the balance of appetite-related hormones, which increases appetite, making people more prone to obesity.
On the other hand, increased sleep quality will maintain a proper balance of the secretion of appetite-related hormones and prevent the intake of unnecessary energy sources. This may lead to prevention of obesity.

Maintenance of health

The rhythm of daily life is regulated and the hormonal balance and autonomic nervous system in the body are improved, then an effect that leads to maintenance of health can be expected. This will also lead to mental health.

Beauty effect

The secretion of growth hormone increases during deep sleep which occurs immediately after sleep onset (non-REM sleep). This growth hormone activates not only health but also skin maintenance and metabolism, which is good for the skin. In addition, it also acts to maintain skin firmness and reduce wrinkles, and therefore it is essential for anti-aging.
Thus, good quality sleep is greatly expected to provide beauty effects.

Lifestyle

Lifestyle is an important factor in improving sleep quality. The lifestyle has two roles. One is a direct role where the habit itself, such as exercise and bathing, provides high-quality sleep. The other is an indirect role where if the body clock that creates a daily rhythm (approximately 24 hours) is adjusted to just 24 hours, well-regulated sleep habits are acquired, which improves sleep quality. Here are specific methods.

● Keep life cycle/bedtime/waking time constant
Sleep and wake-up are regulated by the body clock. Beware that going to bed late on weekends, waking up late on holidays, and excessive napping can disturb the body clock. Establish a habit of going to bed and getting up at the same clock time regardless of weekdays or weekends.

● Exposure to sunlight in the morning
The body clock is reset by exposure to sunlight in the morning, and beats a constant rhythm. When you get up in the morning, open the curtain and shutter, walk outside, etc. to have morning sunlight. It is reported that sleepiness occurs 14 hours after waking up in the morning. In other words, if you get up late, the time when you become sleepy will be late at the same extent.

● Avoid bathing immediately before going to bed, but soak in a tepid bath slowly.
A key to getting good sleep is to activate the parasympathetic nervous system before sleeping. Take a tepid bath slowly 30 minutes or more (preferably 1 hour or more) before going to bed to relieve mental and physical tension. It is known that half-body bathing causes less burden on the heart, makes the parasympathetic nervous system dominant, and improves the quality of sleep.

● Moderate exercise
It is also important to make a habit of moderate exercise. It is said that it is good to perform exercises that make the exerciser a little sweaty in the afternoon, rather than in the morning. Mild physical fatigue provides a peaceful sleep. Beware that a heavy exercise causes stimulation by itself, and conversely delays sleep onset. It is effective to continue aerobic exercises, which are less stressful, for a long time.

● Stress release
Stress is the biggest obstacle to sleep. Find a hobby that suits you, such as music, reading, sports, traveling, etc., to change your mood cleverly and avoid accumulation of stress.

Dietary habit

Diet is also very important for good quality sleep. Try to have the following dietary habits.

● Eat breakfast
Think about nutritional balance and try to eat balanced breakfast (a simple meal has no problem). It promotes wakefulness in the morning and makes a circadian rhythm of sleep and wakefulness.

● Do not eat evening snack before going to bed
Avoid it because digestive activities interfere with sleep onset. However, a very small amount of chocolate, etc. are considered to be good for sleep. If you eat meals at the time you usually sleep, your body clock will be disturbed.

● If you want caffeine, take it by 3-4 hours before bedtime
Caffeine has arousal effects, which may cause difficulty in falling asleep or shallow sleep. It also has a diuretic effect, so you may be awakened during the night. If you want, take it by 3-4 hours before bedtime. People sensitive to caffeine are recommended to refrain from consuming it after 3:00 pm.

● Refrain from nightcap
Alcohol promotes falling asleep, but it is a temporary effect. Similarly to caffeine, it increases the frequency of awakening during sleep, which makes sleep shallow, preventing a feeling of deep sleep.

● Take nutrients expected to improve the quality of sleep
Be aware of nutrition for good quality sleep. We introduce nutrients considered good for sleep and foods that are rich in these nutrients.

Nutrients expected to improve the quality of sleep

Note: Some of these nutrients have an upper intake limit due to the risk of excess intake.

Vitamin B1 in the above table tends to be deficient. Because it is water soluble, then easily lost in the cooking process, and not easily absorbed in the body. Based on the statistics of the daily vitamin B1 intake of Japanese, it is considered that most people are potentially deficient. In particular, there is a statistic that young people often have poor intake.

In such a case, it is one of countermeasures to take “fursultiamine”, a vitamin B1 derivative which improved the weak points of vitamin B1 and is characterized by the following features, from vitamin preparations.

[Characteristic 1] Excellent absorption from the small intestine and other digestive tracts compared to vitamin B1.
[Characteristic 2] Well transferred to tissues such as muscles and nerves.
[Characteristic 3] Abundantly converted to “activated vitamin B1”, a coenzyme which helps the production of energy and maintains normal functions of nerves and other organs, in the body.

Sleep environment

An environment good for sleeping greatly improves the quality of sleep. The points are “bedding”, “temperature/humidity”, and “light”.

● Bedding
Beddings that can maintain a sleeping posture with less impact on the body, and have the ability to hold warmth and absorb/release moisture are conditions for comfortable sleep. It is recommended to select beddings with reference to the followings.
・ A pillow that fits your body and has a low impact on the neck and shoulders
・ A bottom mattress and bed mat with moderate hardness
・ A well-fitted top cover

● Temperature
It may be recommended to keep at around 20℃ in winter and 26℃ in summer for the room temperature and around 40%-70% for the humidity. Use the air-conditioner appropriately.

● Light
A light that is too bright at night can disturb the body clock. It is said that a device shedding a light of not a whitish daylight color but a soft sunset color is recommended.

Improving sleep quality gives various benefits. Lifestyle, dietary habit, and sleep environment are all important for good quality sleep. If there are any problems that interfere with sleep among them, consider measures for resolution. However, it is difficult to solve everything at once in daily life. Improve your daily life little by little, dealing with the problems one by one, without being impatient.
If the problems do not improve despite your efforts, a disease may be hidden. Consult a medical institution early.

Risks and factors of decreased sleep quality