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Internal Clock Disorders / Circadian Rhythm Disorders

Circadian Rhythm Sleep Disorders Specialist in Colorado

The body’s sleep wake cycle is controlled by the internal clock, known as circadian rhythm. Disorders of the circadian rhythm occur when the body’s internal clock is out of sync with the natural day-night cycle. This can lead to sleep disturbances, daytime fatigue, and other health issues.

Types of Circadian Rhythm Disorders:

Delayed Sleep Phase Disorder (DSPD)

Patients naturally fall asleep much later than a typical bedtime (e.g. 2-6 AM) and wake later in the day. It is common among teenagers and young adults.

Advanced Sleep Phase Disorder (ASPD)

Patients have early sleep onset (e.g. 6-9 PM) and early wake time (e.g. 3-5 AM). More common in older adults.

Irregular Sleep-Wake Rhythm

Sleep is fragmented into multiple naps throughout a 24-hour period rather than a consolidated sleep period. It is often seen in individuals with neurodegenerative disease (e.g. Alzheimer’s disease).

Non-24-Hour Sleep-Wake Disorder (Non-24)

Sleep wake cycle shifts later each day, making it difficult to maintain a consistent schedule. Common in blind individuals who lack light perception.

Shift Work Sleep Disorder (SWSD)

Sleep difficulties due to working night shifts or rotating shifts, leading to fatigue and sleep deprivation.

Jet Lag Disorder

Temporary sleep disruption caused by traveling across multiple time zones. Symptoms include insomnia, excessive daytime sleepiness, and digestive issues.

Symptoms of Circadian Rhythm Disorder:

  • Difficulty falling asleep or staying asleep
  • Daytime fatigue or excessive sleepiness
  • Poor concentration or memory problems
  • Mood disturbances (e.g. irritability, depression)
  • Gastrointestinal discomfort

Causes and Risk Factors

  • Genetics: Some people have a naturally delayed or advanced circadian rhythm

  • Light exposure: Artificial light at night (phones, computers) can disrupt the sleep cycle.

  • Lifestyle and Work Schedule: Night shifts, inconsistent sleep patterns and frequent travel can contribute.

  • Medical conditions: Neurological disorders, depression and blindness can impact circadian rhythms.

Diagnosis

  • Sleep diaries: Tracking sleep wake patterns over 1-2 weeks

  • Actigraphy: Wearing a wrist device that monitors sleep patterns through movement and light exposure

  • Sleep study: May be indicated to rule out other causes of sleep disruption

Treatments Offered:

Light Therapy:

Bright light exposure in the morning for DSPD or evening in ASPD helps reset the body’s internal clock.

Melatonin Supplements:

Taking melatonin at a prescribed time can be helpful in shifting sleep-wake cycles (early evening for DSPD, later for ASPD).

Behavioral Changes:

It is important to maintain a consistent sleep schedule (even on weekends). Avoid screens and bright lights before bedtime. Practice good sleep hygiene (cool, dark, quiet room).

Chronotherapy:

Gradually shifting sleep time earlier or later over days/weeks to adjust to a desired schedule.

Medications:

Prescription sleep aids or wake-promoting agents may be used in specific instances.

Management of Jet Lag and Shift Work:

Strategic napping, proper light exposure and timed melatonin use can help with adjustment.

Frequently Asked Questions

What is the role of light therapy in circadian rhythm disorders?

The internal clock and the amount of time you are awake both signal your body when it is time to sleep. Of the two, the internal clock is the primary driving factor. The body’s internal clock is controlled by two factors, light and melatonin release. Exposing yourself to bright light (2000 lux-10,000 lux) at specific times can trick your body’s circadian rhythm into thinking it is earlier or later and time to sleep. The timing of the bright light therapy should be discussed with a physician as improper use can further delay or advance sleep cycles.

Why is jet lag worse in certain places that I travel than others?

The intensity and duration of the disorder are related to the number of time zones crossed, direction of travel, ability to sleep while traveling, and availability and intensity of light. Up to 1/3 of patients do not experience jet lag.