ZINUS JAPAN Co., Ltd. (Head office: Shibuya-ku, Tokyo; CEO: Cho Jin-young), the Japanese subsidiary of ZINUS, a global furniture brand of the South Korean Hyundai Group that specializes in bed mattresses and has expanded its market to 21 countries around the world, conducted an online survey in April 2024 targeting 1,200 men and women aged 20 to 70 nationwide. In response to the question, "Have you ever felt that the quality of your sleep deteriorated when you changed to a new environment such as a new school year, starting school, joining a company, being transferred to a new department, or changing jobs?" nearly half (48.8%) of respondents answered "Yes" or "Somewhat Yes."

With daily rhythms changing and new environments that place stress on the mind and body, it seems that many people are experiencing a decline in the quality of their sleep. Additionally, as we approach May, the risk of May blues increases, a condition that causes a decline in motivation and energy, and in severe cases can lead to serious depression. According to psychiatrist Dr. Yuko Ashizawa, there is a close relationship between the risk of May blues and sleep. We asked Dr. Yuko Ashizawa about measures that can be taken to ensure good quality sleep.

[Supervised by] Dr. Yuko Ashizawa, Psychiatrist and Director of Ichikawa Mental Clinic

He is a certified physician for the Japanese Society of Sleep Research, a designated mental health physician, and a specialist and instructor for the Japanese Society of Psychiatry and Neurology. He treats mental disorders and sleep disorders at psychosomatic medicine and psychiatry clinics. He is also the editor of "GOOD SLEEP BOOK: How to get a good, comfortable sleep 365 days a year" (Shoeisha).

Ichikawa Mental Clinic Ichikawa Building 11F, 1-4-10 Ichikawa, Ichikawa City, Chiba Prefecture

https://www.ichikawa-mental.jp/

This season brings with it the risk of "May Sickness," which is closely related to the quality of sleep.

"May sickness" refers to a depressive condition often medically diagnosed as "adjustment disorder" or "depression." The mental and physical stress and fatigue caused by changes in one's new life environment can cause the brain to function poorly, resulting in symptoms such as mental instability, absent-mindedness, and lethargy. Surprisingly, it can occur not only due to negative stress, such as not being able to adapt to a new environment, but also due to positive changes, such as advancing to higher education, transferring, or getting promoted as desired. May sickness can be caused by obvious stressors, such as changes in the environment, and can lead to a vicious cycle of dwelling on them, which can lead to poor sleep and physical and mental fatigue.

A decrease in the quantity and quality of sleep hinders the recovery of fatigue in bodily tissues. The autonomic nervous system and cranial nerves that control mental condition are also made up of individual cells, so it is important to ensure that nutrients and oxygen are distributed to cells, but if you do not get enough sleep, there is a risk that these systems will not function properly.

• Creating an ideal environment for quality sleep

How to choose bedding to create a stress-free sleeping environment

For mental stability, it is also important to ensure that nutrients and oxygen are properly distributed to the cells of the autonomic nervous system and cranial nerves.

Creating a bedding environment that makes it easy to fall asleep and fully relieves physical fatigue is also important.

If bedding compresses certain parts of the body, it can lead to poor blood circulation while you sleep, hindering the transport of oxygen and nutrients, and the mental stress caused by discomfort can reduce the quality of your sleep.

When it comes to mattresses and futons, there are different firmness and shapes that are suited to each person's body type and sleeping position. Sleeping on your back is ideal for better blood circulation, but ease of turning over is also important. Try lying down on the bedding and check whether it's easy to turn over, whether it puts unnatural pressure on specific parts of your body when sleeping on your back, and whether it's comfortable for you in your sleeping position when you fall asleep before making your selection.

Try out a body pressure distribution measuring device, found in bed manufacturer showrooms, which can visualize how your body's pressure is distributed on the mattress . Avoid bedding that places unnatural pressure on your body (i.e., certain parts of your body sink deeply, causing unnatural weight to be placed on them), and choose bedding that doesn't cause you any discomfort.

How to choose a pillow

The criterion for choosing a pillow is how easy it is to turn over in your sleep. Turning over in your sleep is essential for quality sleep. Staying in the same position can impair blood flow, but turning over in your sleep promotes blood circulation in your body. Another benefit is that it regulates the temperature and humidity inside your bedding.

The ideal pillow is one that is high enough to create a straight line between your forehead, nose, and collarbone when you lie down. A pillow that is flatter and lower than what most people imagine will not hinder you from turning over in your sleep.

About the sleeping space

The lighting should not be completely dark, but rather dim enough that some light can shine through the curtains. Bedding such as sheets and pillowcases should be made of natural materials such as cotton or silk in light, soothing colors, such as blue or green. Sheets that are not very absorbent will not absorb sweat, which will cause discomfort and reduce the quality of your sleep.

• Sleep habits to keep in mind

Maintain a consistent wake-up time

The human circadian rhythm (biological rhythm) is approximately 25 hours, about one hour longer than the 24 hours in a day. To correct this discrepancy, wake up at a consistent time in the morning and reset your 24-hour cycle by exposing your eyes to light in the morning. Exposing yourself to light for a consistent period in the morning also contributes to the normal secretion of serotonin, a hormone that helps normalize the autonomic nervous system and cranial nerves.

diet

Eating delicious food also releases serotonin, known as the "happiness hormone," so it's recommended to enjoy your favorite foods in moderation. However, be careful, as unbalanced nutrition and excessive intake of foods that put a strain on the stomach and intestines, such as carbohydrates and lipids, can increase blood cholesterol and disrupt the intestinal environment in the long term, which can have a negative impact on mental health.

The nutrients necessary for improving the quality of sleep are proteins that make neurotransmitters, vitamin B6, which is essential for the synthesis of serotonin, vitamin B12, which helps the brain and nerves function normally, tryptophan, a raw material for neurotransmitters such as serotonin, norepinephrine, and dopamine, iron, which is said to be essential for the production of dopamine, GABA, which relieves stress and calms excited nerves, and glycine, which increases blood circulation to the extremities of the body and cools the core body temperature.

Foods that improve the quality of your sleep

Include meat and fish in your daily main dishes, and try to actively consume shellfish such as clams and clams, which are rich in vitamin B12, shrimp and sea urchin, which are rich in glycine, and tofu and natto, which are rich in tryptophan. As a staple food, germinated brown rice, which is rich in GABA, is recommended.

Euglena, which is said to contain nutrients that help improve sleep quality, contains 59 types of nutrients, including vitamin B6, vitamin B12, tryptophan, iron, GABA, glycine, and paramylon, a beta-glucan unique to Euglena. A clinical trial in which participants took 1,000 mg of Euglena powder and a placebo powder without Euglena powder for 12 weeks showed a significant improvement in subjective sleep satisfaction. Euglena can be taken in the form of over-the-counter drinks or tablet supplements.

 

- Limit alcohol consumption and only drink caffeine up to five hours before going to bed at night.

Drinking alcohol directly affects the quality of your sleep, and the diuretic effect of alcohol can wake you up during the night, which can also lead to poorer quality sleep. It's also recommended to limit your intake of caffeine, which stimulates the nervous system, to no more than five hours before bedtime.

・Timing and intensity of exercise

Exercise produces fatigue-causing substances such as lactic acid in the body, which helps the body recover from fatigue and makes it easier to fall asleep. Exercise also improves blood flow throughout the body and to the brain, making it easier to process thoughts. By developing an exercise habit, you can build up stamina in the medium term, which can help maintain concentration and motivation at work and may also reduce the risk of May blues, which can be caused by a loss of confidence in work. Ideally, exercise should be done outdoors in the morning, such as a 15-minute walk or more, enough to break a slight sweat.

・Take a lukewarm half-body bath to lower your core body temperature before going to bed

When the body's internal temperature (core body temperature) drops, the parasympathetic nervous system becomes dominant, making it easier to fall asleep. To slow the drop in core body temperature when you go to sleep, in the warm spring and summer months, take a lukewarm half-body bath at 38-40°C at least an hour before bed. Relax in the bath for about 20 minutes.

- Avoid looking at the LCD screen (blue light) of a computer or smartphone one hour before going to sleep

Blue light disrupts your sleep phase (sleep rhythm) by stimulating the brain. Ideally, it's said that it's best to avoid exposure to blue light after the evening. Surfing the web before bed also makes you interested in what you're viewing, which causes your sympathetic nervous system to dominate, preventing your parasympathetic nervous system, which should be dominant when you fall asleep, from functioning properly, making it difficult to fall asleep.

When you can't fall asleep...techniques to help you fall asleep

If the sympathetic nervous system remains dominant before you go to sleep, it will be difficult to fall asleep. Here are some techniques to help you fall asleep by making the parasympathetic nervous system dominant.

• Massage and skin care

・Ear massage to regulate the autonomic nervous system

Stimulating the area around the ears helps to activate the parasympathetic nervous system.

First, pinch the whole ear with your fingers from above and below, then pinch the center of the ear and pull it outward. Then pinch the top of the ear and pull it up, and in the same way pinch the earlobe and pull it down. Repeat this sequence several times.

Aromatherapy before and after sleep is also effective.

It is said that scents directly stimulate the brain and can also help improve the quality of sleep.

Lavender is well known as a scent that helps you relax when falling asleep, but there are also other scents that are recommended for use before falling asleep and when you wake up in the morning.

Recently, skin care brands that focus on aromatherapy have appeared, so incorporating pleasant scents into your skin care products before and after sleep can also help regulate your autonomic nervous system.

You can use it in an aroma diffuser or aroma stone, or put a drop or two on a tissue and place it next to your pillow. Choose natural fragrances, as synthetic ingredients may unknowingly cause stress.

Recommended scents to use before bed: The comforting, sweet scent of geranium and lavender is recommended before sleep.

Clear scents like frankincense and deep forest scents like cedarwood also have a calming effect. The sweet and refreshing scent of orange bergamot is said to relieve tension and stress and leave you feeling refreshed.

Recommended scents for after waking up: Refreshing, cool scents such as eucalyptus and mint, or refreshing bitter scents like tea tree, can be expected to increase the feeling of freshness after waking up in the morning.

 

• Important things for mental well-being

In fact, the best way to maintain mental stability is to "talk to someone you trust."

It is said that feelings of loneliness can worsen depressive symptoms. Other ways to relieve stress for those who find it difficult to interact with others include immersing yourself in a hobby, sleeping, or yelling.

Remember that there is nothing better than maintaining a consistent routine and living a healthy life (eating three meals at consistent times, waking up at the same time, getting enough sleep at a time that suits you, and exercising regularly).

If you are still able to work, see how it goes, but if you wake up feeling exhausted and your body is stuck to the futon and you can't get up, see a psychiatrist as soon as possible.