Risks and factors of decreased sleep quality

Lifestyle

The human body has the “body clock” which makes a daily rhythm (approximately 24 hours). If your life is irregular, the body clock becomes unstable, causing disruptions in the rhythm of sleep and wakefulness.
Why do we need a regular life? The role of the body clock is not limited to determining the timing of sleep. It also regulates hormone secretions and physiological activities in preparation for sleep. These preparations cannot be controlled by your own will. A regular life is the key to adjusting the body clock and smoothly entering sleep programmed in it.

Bedroom environment

Sometimes, the bedroom environment can also be stressful, reducing the quality of sleep. There are cases where you cannot sleep due to a concern about light and sound. In addition, if the temperature and humidity in the bedroom are not appropriate, you cannot have a good sleep.
For example, exposure to bright light at night may delay the body clock. It is said that even with home lighting (illuminance: 100-200 lux), the long exposure delays the body clock. It is also said that the voice of people is a factor that greatly interferes with sleep, and therefore it is bad to sleep with TV or radio on.

Stress

Stress is the biggest obstacle to the quality of sleep. When the sympathetic nervous system in the autonomic nervous system is stimulated by stress and becomes dominant over the parasympathetic nervous system, non-REM sleep which recovers brain fatigue is reduced. Sleepiness is less likely to occur, and even if you fall asleep, non-REM sleep is less, so sleep is shallow, making you wake up many times at night.

In addition to resolving fatigue, good quality sleep also leads to maintenance of our health, such as adjustment of hormone balance or autonomic nervous system and enhancement of immunity.
On the other hand, if the quality of sleep becomes poor, fatigue will accumulate not only in the body but also in the brain, thereby making it impossible to carry out sufficient activities. Then, cognitive functions such as memory, judgment, and concentration decrease. As a result, not only performance in work, study, exercise, etc. is deteriorated, but also there is a risk of leading to major accidents in some cases.
In addition, the risk of developing various diseases including lifestyle-related diseases is increased and the symptoms are worsened. Specific disorders include:

● Obesity
Shorter sleep time decreases the secretion of leptin, a hormone which suppresses appetite, and increases the secretion of ghrelin, a hormone which promotes appetite. The lost balance of these appetite-related hormones increases appetite, making people more prone to obesity.

● Diabetes mellitus
Poor sleep quality can lead to high blood sugar and insulin resistance (a condition in which insulin sensitivity decreases and insulin cannot exert its action sufficiently), which increases the risk of diabetes mellitus.

● Hypertension
Poor sleep quality may increase blood pressure due to increased sympathetic nerve tone, resulting in hypertension.

● Chronic fatigue syndrome
Chronic fatigue syndrome (CFS) is a condition in which a person feels too tired to perform daily activities for a long time despite no objective abnormality in physical examinations or laboratory tests. Many of the patients experience sleep disorders.

We hope you understand that poor sleep quality is associated with various risks. Many of you may have noticed that daily unintentional habits actually interfere with sleep. If you become able to have good quality sleep, your performance will be improved, and you can live a fulfilling day. The quality of sleep will be changed with a little ingenuity, so we hope your efforts.

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