What is circadian rhythm? Circadian rhythms and their disorders

Almost all vital processes in nature go through a cycle. The simplest example of a cycle is the change of seasons. Every year, all living things go through four seasons: spring, summer, autumn and winter. Another example is the cycle of the complete rotation of our planet around the sun. One such rotation lasts a year. Or the complete revolution of the Earth around its axis, forming a day.

In our body, certain cycles also occur. Why does the human body have a need for sleep? Or what contributes to his awakening? What is circadian rhythm? The human body is subject to a 24-hour cycle. The most important thing in this cycle is the change of sleep and wakefulness. This process is automatically regulated by the brain.

The concept of circadian rhythm

Circadian rhythms are a change in the intensity of biological processes that occur in the human body throughout the day. In other words, it’s such a biological clock inside the body. It is impossible to bring down their rhythm, as this is fraught with various diseases of the psyche and vital organs.

Circadian rhythms normally create circadian balance. The state when a person is in good health is called a circadian balance.

With a circadian balance, a person feels physically healthy, he has a great appetite, excellent mood, his body is rested and full of energy. Man is in his rhythm. But when the circadian balance is absent, the circadian rhythm is broken, then this leaves its imprint on the health of the body.

The manifestation of circadian rhythms

Everyone must have noticed for himself that he feels more efficient, energetic and full of vitality and energy at some hours of the day and more exhausted, lethargic and sleepy - at others. This is connected with biological rhythms. About 20 thousand neurons in the hypothalamus are responsible for the work of the biological clock in the human body. It is still not known exactly how these “watches” work. However, scientists are sure that for the normal functioning of the body, their work should be clear and coherent, the circadian heart rhythm should always be normal.

On average, a person’s mental activity has two peaks: 9:00 in the morning and 21:00 in the evening. The physical strength of its peak reaches at 11:00 in the morning and 19:00 in the evening.

The cycle "sleep - wakefulness"

A constant change of day and night is a cycle on which the state of the human body, its circadian rhythm, directly depends. The cycle of changing night and day, responsible for the process of changing sleep and wakefulness. It is from the cycle “sleep - wakefulness” that the course of many processes in the body, its normal functioning and ability to work, depends.

Insufficient sleep can cause a decrease in concentration, a decrease in working capacity. In the absence of a full healthy sleep, intellectual functions deteriorate, metabolic processes in the body are disrupted. This is far from all that the violation of the circadian sleep rhythm is fraught with for the body. It is also fraught with early brain aging, mental disorders and even schizophrenia.

The influence of daylight on circadian rhythms

When the sun goes below the horizon, the level of illumination falls. The human visual system sends signals to the brain. The production of such a hormone as melatonin is stimulated. It helps to reduce human activity. Melatonin relaxes a person, makes you feel sleepy.

Conversely, when the sun appears on the horizon, a signal is sent to the human brain about an increase in illumination. Melatonin production is on the decline. As a consequence, the activity of the human body increases.

Other incentives also take part in adjusting the sleep – wake cycle. For example, taking a shower or bath, the usual wake-up call, going to the bedroom, taking a horizontal position and any other habits.

Sunrises and sunsets

Scientists believe that it is an early rise with dawn and going to bed after the sun goes beyond the horizon will make the work of the biological clock clear and harmonious.

It is for this reason that late dawn and early sunset in winter often lead to people feeling sleepy, lethargic and inhibited. This is a normal body reaction to daylight. A person’s biological clock cannot tune in to normal operation. Daily circadian rhythms fail, and various health problems occur.

The same decline in mood, decline in activity and a feeling of powerlessness are experienced by people who live in the conditions of the polar night or when cloudy, rainy weather lasts a very long time.

Human Chronotypes

Human circadian rhythms are still being investigated. Scientists have suggested that there are three main chronotypes of the human body.

The first chronotype includes “larks” - people of the morning type. They wake up early, with sunrise. The next morning and the first half of the day there is a peak in their vigor, ability to work and cheerfulness. In the evening, the Larks are sleepy; they go to bed early.

The second chronotype includes people of the evening type. They are called "owls." “Owls” behave opposite to “larks”. They go to bed very late and cannot tolerate morning awakenings. In the morning, “owls” are drowsy, lethargic, and their working capacity is extremely low.

Morning retardation of “owls” may be accompanied by a headache. Their performance increases only in the afternoon, more often even after six in the evening. There are times when the peak performance of the “owl” falls at night.

The third chronotype is people with fluctuations in the intensity of physiological capabilities throughout the day. They are called "pigeons" or, in other words - arrhythmias. Such people flow from one extreme to another. They can work equally effectively both in the afternoon and in the evening.

Are “larks”, “owls” or “pigeons” born of people, or do they become so? The answer to this question has not yet been found. However, there have been many studies proving the existence of a relationship between the chronotype and the type of human activity. For example: employees in most cases are “larks”. People working mentally are “owls.” And people of physical labor are “pigeons”. That is, it turns out that a person is able to set his own biological clock himself, to adapt to his rhythm of life. The main thing is not to harm yourself.

Causes of Circadian Rhythm Failure

Violation of circadian rhythms can occur for various reasons. The most basic and common causes of a malfunctioning biological clock:

• Work in shifts.
• Pregnancy.
• Long trip, flight.
• The use of medicines.
• Various changes in the usual way of life.
• Crossing other time zones.
• Owl Syndrome. People with this chronotype prefer to go to bed very late. For this reason, they have difficulty waking up in the morning.
• Lark Syndrome. This chronotype is characterized by early awakening. Such people have difficulties when there is a need to work in the evening.
• When switching to summer or winter time. Many people during this period have a decrease in working capacity, increased irritability, powerlessness, apathy. Moreover, the transfer of hands to winter time is easier to carry than to summer.
• Fans of spending the night at the computer also face a malfunction of the circadian rhythm.
• Night work is a very strong stress for the body. At first, this may not be felt, but with each passing day fatigue accumulates, sleep worsens, working capacity falls, apathy arises, which can be replaced by depression.
• Unforeseen situations when day and night change places.
• Young mothers often suffer from the fact that her circadian rhythms do not coincide with the rhythms of the child. Often in children the main sleep passes during the day, and at night they sleep in small lengths of time. These children are said to have mixed up day and night. Mom, in this case, of course, cannot get enough sleep. This is where a serious violation of the mother’s circadian rhythm takes place.

Circadian rhythm regulation

A person should be able to adapt to any schedule, because life can provide many surprises that can appear extremely negatively at the work of a biological clock. Here are some tips that can help support a person’s circadian rhythms:

• If a person has to fly, then from east to west it is better to choose a morning flight, and from west to east - on the contrary, evening. In this case, before flying westward for five days, you need to try to go to bed a couple of hours later. In the eastern direction, on the contrary - a couple of hours earlier.
• Likewise, going to bed sooner or later, you can prepare for the conversion of the clock hands to summer or winter time.
• It is necessary to try to go to bed no later than 23:00 - this is provided that the dream lasts 7-8 hours. Otherwise, lie down earlier.
• In the case of shift work or some other circumstances, a person should receive his portion of sleep in the other half of the day or, in extreme cases, the next day.
• Do not put off sleep for the weekend. For 4-5 days, the body can get so tired that sleep on the weekend will not be enough. Or something else may happen - there may be a deceptive opinion that there is no fatigue, and insomnia will torment the body. You can not bring the body to extremes, test it for strength. The consequences can be very serious.

Circadian rhythm failure treatment

Circadian rhythm disorders are treated after a diagnosis. The goal of treatment is to return the human body to normal operation, restore the work of his biological clock. The main and most common treatment for circadian rhythm disorder is bright light treatment or chronotherapy. Bright light therapy is used to restore the normal functioning of the human body, to establish the work of its internal biological clock. This technique gives significant results to people who have disturbed circadian sleep rhythms.