The circadian rhythm refers to the changes in your body’s daily biological and physiological processes. The most obvious of these changes is your sleep and wakefulness. The region of our brain that regulates the circadian rhythm is a double center called the suprachiasmatic nucleus and located in the anterior hypothalamus. This center ensures the temperature settings of our body, the adjustment of the sleep and wake cycles, and the regular maintenance of some hormones. These hormones are especially vital hormones such as melatonin, cortisol and growth hormone. This center ensures the regular functioning of the rhythmic working processes of our body. The most important factor affecting these processes is light. Other factors include our social and physical activities. For example, with the decrease of light in the environment, the secretion of melatonin begins to increase. Melatonin has a sleep-inducing hypnotic effect. The presence of light naturally suppresses the secretion of melatonin.
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What is circadian rhythm sleep disorder?
Abnormalities in the processes that regulate the body’s circadian rhythm and conditions that constantly disrupt them cause the rhythm to be disrupted. Thus, situations such as not being able to sleep, waking up early, not being able to sleep or sleeping excessively may occur. These situations also cause negative effects on social life. With circadian rhythm disorder, confusion or shifting of sleep and waking hours to daytime can be seen. For example, falling asleep during the hours you need to work may indicate that your body’s circadian rhythm is disrupted. Such irregularities can be seen in shift workers or those experiencing jet lag. Many of these irregularities are temporary and will usually correct them quickly. However, if you have been experiencing such imbalances for more than 3 months, then a circadian rhythm disorder can be mentioned.
What are circadian rhythm sleep disorders?
Circadian rhythm sleep disorders are classified according to which stage of sleep is affected and why. Below you can see the classification of circadian rhythm sleep disorders:
- Delayed sleep phase disorder
- Early sleep phase disorder
- Irregular sleep-wake rhythm disorder
- free-range sleep phase disorder
- Shift work sleep phase disorder
- Jet lag sleep phase disorder
- Sleep phase disorder not otherwise specified
Delayed Sleep Phase Disorder
Delayed sleep phase disorder is at least 2 hours delay in sleep onset time compared to expected hours. Naturally, the inability to wake up on time in the morning develops. The patient usually complains of not being able to wake up in the morning. For this reason, he experiences negativities in school or work. Examining these patients by keeping a one-week sleep diary facilitates the diagnosis. Since any underlying cause with depressive effects may trigger sleep disorders in these patients, they may also need to be evaluated from a psychiatric point of view.
What is early sleep phase disorder?
Early sleep phase disorder is the state of going to sleep at least 2 hours earlier than expected and waking up earlier. The total sleep time of these patients is normal. Since patients can get the sleep they need, they feel rested despite waking up early in the morning. If the early sleep time is delayed in this picture of insomnia, which is generally seen in advanced ages, when the patient wakes up early in the morning, daytime sleeplessness is felt because the total sleep time cannot be completed.
What is irregular sleep-wake rhythm disorder?
These patients do not have a regular sleep rhythm during the day. The patient sleeps at least 3 times during the day, but these sleeps are of short duration, such as 2-4 hours. Total sleep time is normal. Generally, the suprachiasmatic nucleus in the brain is damaged. This picture can also be seen in cases where light perception is impaired, such as cataracts. Sometimes it can also be seen in conditions that cause brain damage such as Alzheimer’s, head trauma or mental retardation. Sleep hygiene disorders, some drugs, alcohol or substance use can also cause this picture.
What is free-range sleep phase disorder?
These patients have the problem of starting to sleep later and waking up later than the previous day. The synchronization between the patient’s body rhythm and the timing of daylight is broken. It is usually seen in patients who experience complete blindness. There may also be patients who do not have vision problems. They benefit from melatonin therapy.
What is shift work sleep phase disorder?
It is a rhythm disorder in which insomnia or excessive desire to sleep is seen in duty-based workers. In these patients, the risk of occupational accidents increases due to distraction. At the same time, cardiovascular diseases, mood disorders and digestive system problems may accompany the picture. This adversely affects the patient’s quality of life. The problem can be limited with the arrangements to be made in the shift system. It may be beneficial to change the shift periods at least one week apart, to have a bright light source in the working environment, to consume tea or coffee during the work, and to go to sleep in a hygienic environment without delay at the end of the work.
What is jet lag sleep phase disorder?
It usually occurs due to the incompatibility between the body’s own circadian rhythm and the geographical time rhythm of the reached region after long distance inter-regional journeys with a time difference. The body recognizes the geographical rhythm of the other side’s time zone and takes some time to adapt to it. Daytime sleepiness, nighttime insomnia, mood disorders or gastrointestinal complaints may occur. In general, older people are more likely to be affected as it takes longer to adjust. Traveling westward will require sleeping later, and traveling eastward will require sleeping earlier. In order for the body’s own circadian rhythm to get used to these changes, it will be beneficial to prepare according to the travel direction and distance.