Circadian Rhythm Disorder: How Does It Affect Sleep?

written by / July 11, 2019
Circadian Rhythm Disorder - Featured

Nature is based on the principle of cyclicality—the changes of day and night, seasons, years, and so on. These cyclic changes are observed in living organisms as well. The influence of biorhythms on the human body and psyche has been known since ancient times, but the science exploring it—i.e. chronobiology—is a relatively young discipline.

Nevertheless, we know that hampering the body’s 24-hour cycle can impact your physical health, work capacity, and learning processes. In general, a circadian rhythm disorder involves disturbances in the sleep mode. On a basic level, people with these kinds of disorders don’t or can’t fall asleep at the usual hours their bodies naturally require rest.

Historically, the term circadian comes from Latin and means “around the day.” According to science, the circadian rhythm is a self-sustaining autonomous process that periodically alternates between biological states. It also induces natural fluctuations in the intensity of physiological processes and reactions. 

What Is a Normal Circadian Rhythm?

A healthy person’s internal clock counts 24 hours a day. It’s influenced by daylight and darkness at night, which can be reflected in an individual’s shifting energy levels every 20–28 hours. Having a normal circadian rhythm is necessary for the body to regulate its basic vital processes (like pulse and arterial pressure), for the endocrine and nervous system to work effectively, and for you to maintain a general state of activity during the day.

What Is a Circadian Rhythm Sleep Disorder?

The connection between the circadian rhythm and daylight isn’t accidental. We become less active when the circadian rhythm detects less daylight. Our internal biorhythm regulates when we sleep and when we’re awake. Changes in the circadian rhythm can hurt the quality of our lives, so it’s worth knowing what mechanisms are behind them. For this reason, NASA is developing systems that mimic a natural daylight cycle in space to prevent astronauts from losing their internal rhythm, especially for longer flights and space stays.

Considering this circadian rhythm definition, we can establish that some sleep disorders relate to disturbances in our internal clock. These disorders aren’t uncommon. They can manifest as a physical or mental illness or an autonomic sleep dysfunction associated with changes in the circadian rhythm.

This leads to insufficient, excessive, or ineffective sleep. The good news is that modern medical equipment can record an individual’s stages of sleep and then identify any unnatural shifts in their sleep pattern to help discover the source of their problem.

If you’re experiencing any circadian rhythm sleep problems, you should know what keeps your internal clock from operating effectively. Several studies show that a broken circadian rhythm can lead to seasonal affective disorders, bipolar disorders, cardiovascular problems, kidney problems, and cancer, to start. Frequent and prolonged shifts in your daily routine, fatigue, and chronic stress all lead to biorhythm problems. This can begin in the form of common sleep disturbances, followed by general anxiety, increased irritability, neurological and psychological problems, and physical concerns.   

What Causes a Circadian Rhythm Disorder?

Circadian Rhythm Disorder - Blue Light

Among the possible reasons behind the occurrence of circadian rhythm disorders, two are well established:

  • Biological factors – These are any structural or biochemical changes in the parts of the brain that are involved in sleep regulation, such as the hypothalamus.
  • Environmental factors – These are the individual factors that impact our circadian rhythm, for example, working a night shift job or using a cell phone in bed.  

However, having a circadian rhythm disorder causes severe discomfort in the form of chronic sleep deprivation, nervousness, and irritability. The underlying causes of these disorders could be grouped as follows:

  • Lifestyle – This includes frequent travel across time zones, night shift work, regularly visiting nightclubs or bars, and athletic overtraining.
  • Some physiological and non-physiological conditions – This could be pregnancy, severe hunger or thirst, fever, severe pain, and teeth spasms.
  • Diseases – These include infections (like meningitis), gastrointestinal diseases, cardiovascular diseases, headaches, hypoglycemia, or brain tumors.
  • Other sleep conditions – Common ones are chronic sleep deprivation or sleep apnea.
  • Psychiatric conditions – These include generalized anxiety disorder, obsessive-compulsive disorder, post-traumatic stress disorder, chronic fatigue syndrome, schizophrenia, bipolar disorder, neurological disorders (dementia, Alzheimer’s disease), emotional excitement, or anxiety.
  • Consumption of certain substances – These include caffeinated beverages, alcohol, drugs, and medications.

Circadian Rhythm Sleep Disorder Classifications

Since the time we dedicate to sleep is regulated in a homeostatic way, nothing happens if our schedules are upset for a short period of time. This kind of “delay” is adjusted within a few hours, and everything returns to normal. But if your body’s sleep cycle is upset for an extended period of time, then you may have a sleep disorder.

Delayed Sleep Phase Syndrome

More common in young people, this type of sleep disorder is characterized by sleep being delayed until around 2 a.m. or even later. In this case, one might avoid sleep deprivation by sleeping in late.

However, individuals with this syndrome suffer from daytime sleepiness, which impairs their work or school performance. Because of this, patients could be considered lethargic, disinterested, or lazy. The truth is that these “night owls” are productive and creative late at night but chronically tired for any morning duties.

Advanced Sleep Phase Disorder

This circadian rhythm sleep-wake disorder is typical in older people. They prefer to go to bed regularly (with a usual bedtime between 6 p.m. and 9 p.m). This leads to waking up early in the morning (between 2 a.m. and 5 a.m.). People with this syndrome are the so-called “morning larks.” They frequently suffer from sleepiness in the late afternoon or early evening, as well as insomnia in the early morning.

Irregular Sleep-Wake Rhythm

Here, the circadian rhythm is so disorganized that there’s no known sleep or wake pattern. This condition is typical in people with dementia or other neurodegenerative diseases, as well as in children with an intellectual disability. 

It’s thought that this irregular sleep-wake disorder occurs when the circadian rhythm degenerates or isn’t exposed to adequate day/night light patterns. The most common side effects are insomnia and excessive daytime sleepiness.

With this disorder, sleep becomes fragmented—over a 24-hour period, people may take a series of naps to get an average amount of sleep.

Non-24-Hour Sleep-Wake Disorder

Here, the circadian rhythm for sleep shifts to a little later every day. Up to 70% of blind people could be affected by this disorder, although it can occur in sighted people as well. When it becomes impossible for someone to synchronize their internal clock based on light exposure, they’ll follow a day-night pattern that’s either determined by other people or by their own internal clock (which is proven to be genetically defined). 

For this circadian rhythm disorder, blindness causes a patient’s sleep and wake pattern to occur around 30 minutes later each day, resulting in a shifting sleep schedule. This is because the internal clock is genetically coded to run at 24 1/2 hours in length. The side effects are insomnia and daytime drowsiness, especially if this continues for several weeks.

Jet Lag

Can you change your circadian rhythm? Jet lag puts the question to the test. When our internal sleep and wakefulness routine conflicts with the patterns in a new time zone, this condition is the result. Usually, it’s difficult for an individual to fully adjust to the new time zone. The good news is that there are some tips on how to overcome and avoid jet lag. Keep in mind, traveling east is even more complicated than a westward trip because it’s easier to postpone going to sleep than it is to make yourself sleep earlier.

Shift Work Disorder

This disorder is very common considering how many people work rotating shifts or work overnight. People have different circadian rhythms, which can be damaged by irregular work schedules. When someone’s internal biological clock is thrown off this way, this eventually leads to difficulties adjusting to the day’s changes.

Shift work disorder is characterized by continual and repeated sleep interruptions that result in insomnia or excessive sleepiness. It can also cause the development of more serious psychiatric problems.


Narcolepsy could also be considered a sleep disorder related to the circadian rhythm. People with this condition experience extreme daytime drowsiness and even lethargy. These symptoms are combined with episodes of falling asleep during the day—no matter whether a patient already had enough sleep the night before.

Circadian Rhythm Disorder: Symptoms and Diagnosis

Circadian Rhythm Disorder - Symptoms

A given person with this type of sleep disorder may sleep well. However, due to alterations in the sleep-wake rhythm, the most common consequences are daytime drowsiness and insomnia. These are the two main symptoms of these disorders. If you sleep poorly and wake up several times a night, this may indicate a problem with your circadian rhythm.

Since the differential diagnosis is broad, it’s essential to exclude other medical disorders, including narcolepsy, which can simulate delayed sleep phase disorder.

However, it’s a challenge to diagnose these disorders. With this in mind, any diagnosis should be made by a sleep specialist who offers individual treatment. Before your appointment, it’s a good idea to prepare a sleep log for your last two weeks, and don’t forget to describe your sleep history in detail. 

Circadian Rhythm Sleep Disorder Treatment Options

Treatment is based on two approaches: progressing or delaying when you go to sleep and when you wake up. It’s common to use melatonin in pill form, since the human body already naturally produces this substance to regulate its circadian rhythm. In fact, the production of melatonin in relatively high levels is associated with the onset of sleep. Conversely, exposure to light delays sleep.

To achieve an optimal ratio in your circadian rhythm’s sleep and wake cycle, you can make some mild alterations to your routine. The following are some ways to alleviate certain circadian rhythm sleep disorder symptoms:

  • Try soothing the nervous system with a soft light so you can fall asleep at the convenient and proper time.
  • Adjusted your bedtime gradually.
  • Consistently wake up at the same time.
  • Avoid conflicts and stressful or emotional situations.
  • Start a new hobby.
  • Play a sport, run, or go swimming during the day.
  • Try yoga, pilates, or stretching.
  • Consider psychotherapy.
  • Perhaps visit a health resort or SPA.
  • Go to the cinema, the theater, a concert, or another event you enjoy.
  • Take a walk in nature or go on a trip.

An additional circadian rhythm disorder treatment option is to take prescribed medications. But this is for more severe cases. For example, if the disorder is severe or has been going on for some time, it’s best to seek medical help. Some severe cases, like those associated with shift work and business trips, may even require a patient to consider transferring to a more appropriate job.


What happens if your circadian rhythm is out оf whack?

Our biological clock, also called our “circadian rhythm,” primarily manages our sleep/wake cycle. Most people notice that they experience different levels of drowsiness throughout the day or that they have trouble falling asleep during the night.

The circadian rhythm works with functions that are synchronized with your sleep/wake cycle—such as body temperature, hormone secretion, urine production, and blood pressure changes. If there’s a problem with the internal rhythm, then we can expect variations in these same processes.

How long does it take to reset your circadian rhythm?

Controlled by the body’s so-called biological clock, the circadian rhythm refers to the physiological and mental cyclical changes that the body undergoes throughout the day. 

The photosensitive retinal cells in the eye contain melanopsin pigment, which responds to the pupil’s reaction to light. One of their functions is to “restart” the circadian rhythm upon detecting light.

Unfortunately, these cells also respond to shortwave LED light (blue and green), which is widely used in TVs, tablets, laptops, and mobile phones. Because so many people use their devices right before bed, in the morning they’ll feel drained and unprepared for the day. They can also have problems falling asleep, which will eventually mess up their circadian rhythm.

When you need to tweak your sleep schedule for some reason, there are a few simple steps that you should follow. If you’ve changed your time zone and jet lag has affected your circadian rhythm, this process can take up to a few days to reset. However, if you suffer from a sleep disorder, such as delayed sleep phase syndrome, it can take up to a couple of months.

How do I fix my internal clock?

There are a few things you can do if your internal clock is thrown off:

  • A short daytime nap won’t significantly affect your circadian rhythm, but it can have a pretty rejuvenating effect.
  • Regulate your diet—eat moderately such that you neither overeat nor feel hungry.
  • Monitor your sleep—watch whether you’re sleepy all day or at certain times of the day.


Despite the wide range of sleep medications available, it can be hard to manage sleep disorders related to our internal clock. Every circadian rhythm disorder requires a different approach for identification and treatment, in which the only goal is to normalize the circadian biorhythm and avoid developing a new sleep disorder.

At medical school, it was easy to realize that sleep is crucial while studying during the many sleepless nights I spent. As a new mom, when the lack of sleep became even more evident, this was the real moment when I started appreciating the benefits of a good night’s sleep. Since sleeping is so essential to our health and immune system, I took it upon myself to educate people on different aspects of sleep by sharing the valuable information I have learned.