Circadian rhythm and sleep disorders What we need to know

14.02.2024

Table of Contents

What is a circadian rhythm?

The human circadian rhythm is a type of sleep-wake cycle during the day and night. It provides control over a person's sleep and wakefulness schedule. The circadian rhythm is influenced by light and dark periods and other factors. In response to signals from the environment, the nervous system changes activity levels, secretes specific hormones, changes body temperature and metabolism, and thus regulates the sleep-wake cycle.

Under the influence of external factors and sleep disturbances, circadian rhythms may be disturbed, which not only causes discomfort to a person, but also causes a number of diseases. Healthy habits help maintain the circadian rhythm and physiological sleep-liver regime.

How does the circadian rhythm work?

One of the important regulators of circadian rhythms is - hypothalamus suprachiasmatic nucleus, which secretes a hormone to melatonin.

Several components provide a human circadian rhythm. It is one of the biological rhythms of the human body.

cells

Specific cells in the brain regulate the alternation of light and darkness, which is perceived by the retina of the eye. Impulses from these cells are sent to other cells of the brain, which activate one or another function and cause the person to wake up or arrange for sleep.

Hormones

Hormones such as melatonin and cortisol affect circadian rhythms and increase or decrease the body's activity.

Melatonin It is a hormone that is produced in the nucleus of the hypothalamus and which prepares a person for sleep. Active production begins at night, with darkness. During the day, its secretion is inhibited.

Cortisol The main hormone of wakefulness, actively begins to be released in the morning, when waking up.

Other hormones also play an important role in alternation of the sleep-wake rhythm:

Vasopressin - Antidiuretic hormone. It is produced in the suprachiasmatic nucleus of the hypothalamus. It participates in the fluid balance of the body, regulates the volume of blood, its temperature and the formation of urine in the kidneys.

Acetylcholine - It is actively produced in the phase of wakefulness and fast sleep (REM sleep). Participates in the processes of vigilance and information memorization.

Insulin - The activity of insulin beta cells changes significantly during periods of sleep and wakefulness. This leads to suppression of insulin secretion during sleep and active production after waking up.

Leptin - a hormone produced by fat (adipose) cells. The peak of discharge is at night. This hormone regulates the activity of the suprachiasmatic nucleus and promotes the production of melatonin at night. Leptin levels rise after a meal and cause a feeling of fullness. Improper eating and sleeping patterns disrupt this delicate balance and cause both circadian rhythms and metabolic disorders and obesity.

other factors

Body temperature and metabolism are also components of circadian rhythms. During sleep, the body temperature decreases, and when waking up, it rises again. The level of metabolism activity is also different in different parts of the day.

Circadian rhythm changes can be caused by factors such as:

working hours
physical activity
stress
Anxiety
Lifestyle and habits

Age is an important factor. Circadian rhythms are different in children, adolescents and adults.

Circadian rhythm in children

A baby's circadian rhythm is not clearly expressed at birth and is formed only after a few months. For this reason, it is common for babies to have a disruption of the day-night rhythm, for days, weeks and even months. Infants' circadian rhythm is formed in response to environmental influences and changes in their bodies. The production of melatonin in infants begins at the age of about 3 months, and cortisol - at the age of 2-9 months.

The sleep-wake regime of older children is clearly established, influenced by the maturation of circadian rhythms and bodily functions. On average, children need 9-10 hours of sleep a night.

Circadian rhythm in adolescents

In adults, the so-called In teenagers, there is a change in the circadian rhythm known as "sleep phase shift". Unlike younger children, the release of melatonin in adults is not stimulated until 10-11 p.m., which is why adults who wake up early in the evening do not feel the need to sleep and cannot fall asleep.

The same change in the circadian rhythm causes the need for longer sleep in the morning in adults.

Circadian rhythm in adults

Adults' circadian rhythms are well established if they follow healthy habits. Adults usually need to sleep before midnight, which coincides with the peak of melatonin secretion. Also in adults there are periods of lack of energy and fatigue between 1-3 and 2-4 hours of the day.

With age, a change in the circadian rhythm is noticeable. In old age, people go to sleep much earlier and wake up in the early hours of the morning. This process is normal along with other age changes.

What factors alter circadian rhythms?

Often, lifestyle features conflict with circadian rhythms. The reason for this may be:

Night shift
Duty during non-working hours (early in the morning or late at night)
Travel across time zones
A lifestyle that makes us wake up early or go to bed late at night
Medications
stress
mental health problems
Such pathologies as: brain injuries, dementia, head trauma, blindness and others.
Bad sleep habits – irregular sleep schedule, eating late, staring at the screen for a long time before going to bed, etc.

When moving to different time zones in a short period of time, the body cannot adapt to the new environment, which is manifested by the feeling of fatigue and sleepiness during the day and wakefulness at night. Adaptation of the circadian rhythm to a new environment may take several days or even a week.

How to restore the circadian rhythm?

The circadian rhythm can be disrupted by various factors, but there are some tips to restore a healthy circadian rhythm:

Follow a daily routine
To increase the quality of alertness, spend maximum time in the sun during the daytime hours
Be physically active throughout the day
It is necessary to sleep in an environment conducive to sleep - with suitable temperature, lighting and a comfortable mattress.
Avoid alcohol, caffeine and nicotine in the evening
Limit screen time before bed
Avoid short naps in the afternoon

sleep disorders

Sometimes a circadian rhythm disturbance can be a sign of a more serious problem - sleep disturbance. It is important to have a place for early phase and late phase sleep disorders. Irregular work schedule, poor eyesight, adolescence or old age - contribute to the formation of sleep disorders.

Late phase sleep disorder is characterized by waking up 2 or more hours after falling asleep, when it is difficult to fall asleep again. This form of sleep disorder is more common in adolescents and young adults.

In the early phase of sleep disorders, Adayans fall asleep in the early hours of the evening and wake up very early in the morning.

Circadian rhythm disorders may lead to difficulty falling asleep, frequent awakenings at night, and difficulty falling asleep again. This condition causes the following symptoms:

Insomnia
Difficulty falling asleep
Difficulty waking up Dilit
Fatigue during the day
Feeling depressed or stressed

What is the harm to health caused by the disruption of the circadian rhythm?

Maintaining a physiological circadian rhythm is vital. Its disruption has a significant impact on health both in the short term and in the long term and causes changes in the functioning of the cardiovascular system, digestive system, metabolism, skin and other organs. A person becomes more prone to diabetes, obesity, and mental pathologies.