Sleep-Wake Rhythm Disorders

Last updated: April 6, 2019

The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. Read our full medical disclaimer.

Just like any other living organisms, humans have various biological rhythms. One of these is the Circadian Rhythm. The Circadian Rhythm is often called the body clock or the biological clock. Among other things, the Circadian Rhythm controls sleep timing. Because of the Circadian Rhythm, a person’s sleepiness doesn’t continuously increase throughout the day. The ability to fall asleep is dependent on the amount of time since that person woke up and on the internal body clock. This means that a person gets sleepy and wake up at relatively specific times of the day.

However, when a person has a sleep-wake rhythm disorder, that person’s sleeping and waking time doesn’t follow a discernible pattern. They are unable to sleep at their desired sleeping time. If they do fall asleep, they are unable to sleep for long stretched. As a result, they often take several naps throughout the day in order to compensate for the loss of sleep.

What are the symptoms of a sleep-wake rhythm disorder?

When a person has a sleep-wake rhythm disorder, he may experience one or more of the following symptoms:

  • Inability to sleep at night
  • Frequent arousals during the night
  • Difficulty in waking in the morning
  • Excessive daytime sleepiness
  • Frequent naps throughout the day

What are the common causes of Sleep-Wake Rhythm Disorders?

The human body’s Circadian Rhythm is dictated largely by the light absorbed through the eyes. This explains why these disorders are more common to the blind and to the elderly. Significant changes in the regulation of the Circadian Rhythm comes with aging. The elderly are also more likely to develop problems with the lens of the eyes, like cataracts, which makes light absorption more difficult. The tendency to develop Sleep-Wake Rhythm Disorders are further exaggerated in adults suffering from neurodegenerative disorders like Alzheimer’s disease and dementia.

On the other hand, blind people have no way of absorbing light which leads to a decrease in melatonin levels.

What are the types of Sleep-Wake Rhythm Disorders?

There are two types of disorders under this group.

Irregular Sleep-Wake Rhythm Disorder is a rare condition where there is no defined Circadian Rhythm. A person with this kind of disorder doesn’t follow a particular sleep-wake pattern. They can easily fall asleep but they are unable to stay asleep for long. This inability to stay asleep for long periods results in the patient requiring several naps throughout the day to compensate for lost sleep. Unlike with other sleep disorders, those with Irregular Sleep-Wake Rhythm Disorder can still get enough sleep over a 24-hour period. However, their sleeping time is distributed over several short periods.

The second type of Sleep-Wake Rhythm Disorder is the Non-24 Hour Sleep-Wake Disorder. This is a disorder wherein the Circadian Rhythm is not aligned with a 24-hour schedule. People with normal Circadian Rhythms follow a sleep-wake cycle that is a little longer than 24 hours. When a person has Non-24-hour sleep-wake cycle, their circadian rhythms get progressively longer. This results in sleep and wake times moving to a later time each day.

How are these disorders treated?

The first line of treatment for these disorders is changing one’s sleeping habits. Patients are encouraged to stick to a regular bedtime and waking time each day. They are also encouraged to avoid activities that can interfere with their sleeping and waking times like drinking caffeine and alcohol close to bedtime. These changes in lifestyle are often coupled with improvements in the sleeping environment. This includes ensuring that the bedroom is free from disruptive noises, or maintaining a room temperature that is conducive to sleeping.

Some doctors also recommend taking melatonin supplements and undergoing light therapy. These are effective methods that have helped people with these disorders.

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The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. Read our full medical disclaimer.