What is Circadian Rhythm?

The circadian clock is the “internal body clock.” This clock regulates bodily functions on a daily basis, including a person’s sleep habits. The rhythm generated by that internal clock is the circadian rhythm. Sleep and wakefulness follow a circadian rhythm.

What Are Circadian Rhythm Disorders?

When an individual’s internal circadian clock is not in sync with the external clock, it may result in the development of circadian rhythm disorder. The sleep disorder manifests as an inability to fall or stay asleep, as well as excessive daytime sleepiness, with significant impact on health outcomes and impairment in social and occupational performance.

What are the Different Types of Circadian Rhythm? 

Circadian rhythm sleep disorders include delayed sleep phase syndrome, advanced sleep phase disorder, shift work disorder, and jet lag.

Delayed Sleep Phase Syndrome

Delayed sleep phase syndrome is commonly seen in adolescents or young adults and is characterized by theinability to fall asleep until very late. These “night owls” are most productive at night and can often be chronically tardy or inefficient for early day obligations, like school or work.

Advanced Sleep Phase Disorder

Advanced sleep phase disorder is typically seen in the elderly. Those suffering from this sleep disorder tend toawaken very early in the morning and become very sleepy early in the evening.

Shift Work Disorder

Shift work disorder is seen in individuals who are constantly rotating shifts or work schedules, thus disrupting the internal circadian clock. This can result in insomnia or excessive sleepiness.

Jet Lag

Jet lag occurs when the internal clock is thrown off due totravel into a new time zone. The body often requires a period of adjustment to get back on a regular sleep cycle. When someone regularly travels between time zones, this can become a chronic sleep disorder.

What are the Symptoms of Circadian Rhythm Sleep Disorders?

Some symptoms commonly seen in persons with a circadian rhythm disorder include:

• Inability to fall asleep at night
• Repeated waking in the middle of the sleep cycle
• Excessive daytime sleepiness
• Inability to concentrate
• Poor performance at work or school

What are the Risk Factors for Circadian Rhythm Disorders? 

The following factors may increase the risk of having or developing a circadian rhythm sleep disorder:

• Tendency to be a “night owl”
• Having family members with sleep disorders
• Lack of exposure to morning sunlight
• Excessive exposure to bright light in the evening
• Poor sleep hygiene
• Occupation that requires irregular shifts and work hours
• Frequent travel between different time zones

How are Circadian Rhythm Disorders Diagnosed?

If you believe you may be suffering from a circadian rhythm sleep disorder, it is important to schedule an appointment with a sleep specialist, such as Dr. Malhotra, who can evaluate and diagnose your condition. Making a diagnosis typically begins with a physical examination, medical history, and sleep history evaluation.