Circadian rhythm disorders

When the biological clock fails and periods of wakefulness and sleep are not synchronized with external situations of light and dark, circadian rhythm disorders occur. The wordcircadian´ is formed by two parts: circa Y ten. The combination of both in Latin means ´around the day´.

The circadian rhythm is marked by changes that occur in the body throughout the twenty-four hours of the day. These changes are usually regular. In most people, the waking time is basically the same every morning, and the sleeping time is also the same at night.

While there are internal genetic factors that regulate the circadian rhythm, it could be said that Light as an external factor is the main regulator of the biological clock. The area of ​​the brain known as the circadian pacemaker is responsible for interpreting the light it receives to order the body as a whole to wake up or be sleepy.

External light enters the eye and stimulates the retina, which is the layer of impulse receptor cells at the bottom of the eyeball. The impulses generated there are transmitted to the Circadian pacemaker of the brain that will increase or decrease the production of the substance called melatonin, which promotes sleep.

Causes of circadian rhythm disorders

Among the different causes that can cause circadian rhythm disorders we can differentiate internal and external types.

Internal causes

  • Brain injuries: Alzheimer's disease, for example, or head trauma that compromises the brain. Also aftermath of a stroke or an infection in the upper central nervous system, such as encephalitis.
  • Psychiatric disorders: Scientific studies have shown the association between various psychiatric diseases and alterations in the biological rhythm.
  • Insensitivity to the day and night cycle: It is a particular condition in which the brain is unable to determine the changes in the cycle of external light, so it does not generate the usual rhythm of sleep and wakefulness.

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External causes

  • Long trips that span different time slots: long air travel especially from west to east.
  • Work in rotating shifts: when daytime schedules alternate with nighttime schedules continuously.
  • Lack of regularity of schedules: in people who because of their lifestyle do not have a routine habit of waking and bedtime schedules.
  • Prolonged prostration: the long-term stay in bed, due to disabling pathologies, for example, alters the biological clock. It happens frequently in hospitalized people.
  • Medicines: Some drugs prescribed for other disorders have drowsiness or overstimulation as adverse effects.

Night work shifts affect the circadian rhythm. It is also affected by having an irregular schedule for waking up and going to bed.

The five disorders of the circadian rhythm

Science has cataloged five entities within the circadian rhythm disorders. We will describe them in the following space:

Time lag or jet lag syndrome

This is the disorder caused by a plane trip that crosses different time zones. By making the change in such a short time, the body loses the references of moments for rest and activity.

Shift-associated disorder

Workers who are scheduled to perform tasks in day and night shifts suffer from this alteration. According to studies, between five and ten percent of workers with rotating shifts suffer from altered biological clock. It will always be less harmful for the shift to be fixed at night, provided it is a matter of rotations between day and night.

Delayed sleep phase disorder

In general it is an affectation of young people, since it is generated by the displacement of bedtime and getting up. When a person regularly goes to bed late and gets up late, it is difficult to fall asleep early on the day he needs to do it.

Advanced sleep phase disorder

Unlike the previous one, those who go to bed early and wake up early suffer. Of course, it is more common in the elderly than in young people. Once the pattern is established, it is difficult for the sufferer to stay awake for more hours during the night.

To continue reading: How to treat daytime sleepiness naturally

24-hour sleep and wake syndrome or non-synchronization syndrome

This has been described in blind people, affected by ocular non-sensitivity to external light. In them, periods of sleep and wakefulness maintain their length, but can last more than twenty four hours.

Jet lag is one of the forms of circadian rhythm disorders.

How these disorders are treated

The first option to treat circadian rhythm disorders is the modification of habits, looking for the coincidence with the light of day. The use of natural or artificial intense light is also a strategy.

Those traveling at risk of jet lag should be exposed to sunlight at the destination as soon as possible, to change the indications of the biological clock. Night workers should have intense artificial light in their workplace to simulate daylight.

As for drugs for these disorders the best known is melatonin. Artificially this substance tries to replace the body melatonin. Its use is common among frequent travelers suffering from jet lag. It is assumed that short-term use has no adverse effects. In any case, it is always preferable to take non-pharmacological measures.