Lack of sleep not to be ignored.
What is the importance of sleep and how to improve it?

What is the state of lack of sleep?

Lack of sleep refers to a state where a person does not have sleep necessary for him/her.
An appropriate amount of sleep time required is considered to be approximately 6-8 hours for Japanese adults although it varies among individuals. The National Sleep Foundation in the United States recommends that adults aged 26-64 years should sleep for 7-9 hours. Thus, the length cannot be determined categorically.
Lack of sleep occurs not only when necessary sleep time cannot be taken, but also when there are problems with the quality (depth) of sleep or regular sleep rhythm.

Importance of sleep

Sleep is a physiological phenomenon that is very important for recovery of mental and physical fatigue, and directly linked to mental and physical health of all people.
For example, the action of the brain is greatly affected by sleep. The weight of the brain is about 2% of body weight, but the brain consumes as much as 20% of energy that used by the body. Most of its energy depends on glucose, and the brain is said to consume approximately 25% of glucose required by the entire body.
However, if you continue to wake without sleep, the brain cannot successfully use glucose as energy, thereby the brain nerve cells are exhausted and become difficult to work.
Sleep recovers this condition. An experiment in rats showed that the impaired ability to use glucose due to lack of sleep for 5 days returns to near normal levels after only one day of sleep. In humans, it takes more time to recover, but it is suggested that its surprising recovery capacity is the intrinsic function of sleep.

Signs of lack of sleep

Daytime sleepiness is a sign of lack of sleep. Sleepiness particularly in the morning corresponds to it. We often experience sleepiness after lunch, and this is considered as physiological sleepiness caused by the body clock (i.e., the basic function of the body such as keeping the body temperature and secreting hormones has a rhythm of about 24 hours).
If you feel a trivial change in your daily life, such as “work does not advance”, “learning is not as expected”, or “there are many unusual mistakes”, it may be a sign of lack of sleep.
If lack of sleep is suspected, look back at your previous night's sleep time and quality. It is also effective to compare sleep hours on weekdays and on holidays. If you sleep longer on holidays than on weekdays, you may have a chronic lack of sleep.

Amplification of fatigue

One mechanism that causes sleepiness is a “desire to sleep” that occurs from fatigue accumulated during waking hours. The longer you wake up, the more the desire to sleep increases. For example, a person who is awake for a long time due to working throughout the night, etc. can enter sleep immediately even if he/she is usually a bad sleeper. If the desire to sleep is not satisfied due to lack of sleep, the brain and body cannot take sufficient rest, and the accumulated fatigue remains, thereby amplifying the feeling of fatigue.

To be a cause of various diseases

It is known that people with lack of sleep have high risks of lifestyle-related diseases such as obesity, hypertension, diabetes mellitus, hyperlipidemia, cardiovascular disease, and cerebrovascular disease. For example, it is reported that approximately 30% of people who are treated for hypertension and 37% of diabetic people are suffering from insomnia. Also, it is said to relate to psychiatric diseases, such as depression. The most common initial symptoms of depression are poor sleep quality and insomnia.
Then, not only lack of sleep, but also poor sleep quality can cause disorders. For example, many people with chronic fatigue syndrome (CFS)* experience poor sleep quality. Parasympathetic nerves predominate during sleep in healthy individuals, but do not in patients with chronic fatigue syndrome, and it is considered that a high sleep quality cannot be obtained even if adequate sleep time is secured, which makes fatigue chronic.

*Chronic fatigue syndrome (CFS): A disorder in which symptoms of severe general malaise, slight fever, lymphadenopathy, headache, muscular weakness, sleep disorder, impaired ability to think/concentrate, etc. that markedly interfere with daily living do not resolve even after rest, persisting for a long period of more than 6 months.

Increased stress

When you get closer to the habitual bedtime, your brain will slowly relax and you eventually enter sleep. Brain fatigue resolves with sleep. For this reason, if you cannot sleep sufficiently, brain fatigue accumulates, and you are prone to stress-related health disorders such as unstable mood and emotion including irritability.

Decline in cognitive function

If brain fatigue accumulates due to lack of sleep, the ability to concentrate, memorize, and think also decreases. These cognitive functions are also important in maintaining mental health.
A study in healthy volunteers showed that lack of sleep can lead to development and worsening of anxiety, depression, persecutory delusion, etc., and cognitive decline. This can lead to poor efficiency and errors in work and learning.

Easier to gain weight

Several studies also clarified that lack of sleep can predispose people to obesity.
A mechanism is considered that if a short sleep time continues, it disrupts lifestyle such as diet and exercise, thereby making it easier to gain weight. In addition, lack of sleep increases the secretion of ghrelin, a hormone which promotes appetite, and decreases the secretion of leptin, a hormone which suppresses appetite. Further, the secretion of cortisol, a stress hormone which is involved in increased dietary intake and visceral fat, also increases. Changes in the secretion of these hormones increase the intake of energy sources, and if the use of energy by exercise, etc. is not sufficient (the consumption of energy sources is not sufficient), the energy sources will be changed to accumulated fat, leading to weight gain.

Dietary habit

Your dietary habit is also very important to prevent lack of 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.

● 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.

● 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.

● 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

*Sleep consists of two types of sleep that differ qualitatively; i.e., “REM sleep” and “non-REM sleep”. Generally, it is said that brain (mental) fatigue recovers during non-REM sleep and body fatigue recovers during both types of sleep, especially during REM 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 rhythm

People fall into a natural sleep at night with the action of the “body clock” that beats a rhythm at one-day (about 24 hours) cycle.
Therefore, it is important to establish a habit of getting up and going to bed at the same clock time regardless of weekdays or weekends. Beware that going to bed late on weekends, waking up late on holidays, and excessive napping can disturb the body clock.
However, you need not stick to it because the amount of sleep time required varies among individuals. It is not recommended to set a goal such as “I want to sleep for XX hours”.
Also, there may be occasions when you go to bed, but do not become sleepy. If you spend too much time in bed, you will have less feeling of deep sleep. In such a case, it is better to get out of bed daringly.

Utilization of light

The body clock is reset by exposure to light every morning, and beats a constant rhythm. The cycle of the body clock is longer than 24 hours, and therefore we need to put the clock forward daily. The morning light has the action to put the delayed body clock forward. When you get up in the morning, first open the curtain and shutter, and take the natural light into the room.
In contrast, the light at night has the power to delay the body clock. Beware that if you get too much light at night, your body clock will be delayed, making it hard for you to wake up early and giving a negative effect on your sleep.

Exercise habit

Moderate exercise promotes sleep onset, reduces awakening during sleep, and improves sleep quality. Since the effect is weak with just one exercise, it is important to continue the exercise regularly. It is reported that the effective timing of exercise is from evening to night (about 3 hours before bedtime).
Aerobic exercises that make the exerciser a little sweaty, such as rapid walking, light jogging, and stretching which are less stressful and can be continued long, are effective.
However, exercising immediately before going to bed will excite the body, and therefore should be avoided.

Napping

It is ideal that people can live with a constant rhythm every day and have sufficient sleep, but it may not be possible to get necessary sleep at night due to work, errand, etc. In such a case, take a nap early in the afternoon. Try to nap for a short time (within 30 minutes) because you may have bad awakening if sleep too long.

Relaxation method right for you

Stress is the biggest obstacle to high-quality sleep. Set up a “relaxation time” before going to bed to refresh and relieve your mental and physical tension.
Try to find a relaxation method right for you; e.g., listening to your favorite music, reading a light book, soaking in a tepid bath slowly, being covered with a fragrance you love ..., etc.

There are many factors that cause lack of sleep in our lives. There may be a tendency to lead to lack of sleep in the modern life.
The causes of lack of sleep are not limited to stress and irregular life habits. There are various factors such as physical and mental diseases, intake/uptake of drugs and irritants, and inappropriate environments including noise, light, or sound in the bedroom. Try to remove these factors causing lack of sleep one by one to improve your living environment little by little, so that you can have adequate sleep.
If your sleep shortage does not improve despite your efforts, consult a medical institution early.