Circadian Rhythm Disorders

The natural patterns of sleepiness and alertness which happen throughout the day are dictated by circadian rhythm, or our body’s internal clock. When our sleep pattern is disrupted, the result is a malfunction of the internal body clock, a mismatch in the external environment regarding the timing and duration of when we should be asleep. People with circadian rhythm disorders experience insomnia at certain time and excessive sleepiness at others, which results in impairment at work, at school, or socially.

The circadian biological clock regulates the timing of sleepiness and wakefulness throughout the day, with dips and rises at different times. In most cases, adults have the strongest sleep drive between 2 and 4 a.m. and in the afternoon between 1 and 3 p.m. However, this may vary depending on whether you are a “morning person” or a “night owl”. This progression may also be determined by on whether you have had adequate sleep or if you are sleep deprived. Circadian rhythm accounts for a more alert feeling at certain pounds in the day, whether or not you have been awake for many hours.

During adolescence, changes occur to circadian rhythm when teenagers experience a sleep phase delay. This makes teens naturally feel more alert later at night and makes it difficult for them to fall asleep before 11 p.m. Because of this, many teens don’t get adequate sleep because they have to wake up early for school or other commitments. This can create some issues because it is recommended for teenagers to get an average of 8.5 to 9.5 hours of sleep per night. The resulting sleep deprivation can alter circadian rhythm, and teens tend to experience the strongest sleep drive between 3 and 7 a.m. and between 2 to 5 p.m. The morning “dip” can be even longer if a teen is sleep deprived, lasting until about 10 a.m.

Exposure to light in the morning makes the brain send signals to raise body temperature and to produce hormones such as cortisol. Melatonin, a sleep-promoting hormone, levels off with light exposure and increases again when it is dark and as bedtime approaches.

Disruptions to circadian rhythm, such as traveling across time zones, can conflict with natural sleep patterns. This shift in time zone radically changes the light cues and forces the body to alter its normal sleep/wake cycle. These symptoms can occur in everyday life, too, when circadian rhythm is disrupted by keeping irregular hours, such as with shift workers. For these reasons, it is important to keep a regular sleep/wake schedule to perform at your best.

The following are common circadian rhythm disorders:

Delayed Sleep Phase Disorder

This disorder is common in adolescents and teens whose tendencies to stay up late and preference to sleep in late affects their lifestyle. However, because teens generally have to wake up early for school, the result is daytime sleepiness and impaired school performance. Teens may be misunderstood as lazy, unmotivated, and underachieving for exhibiting the signs of chronic sleep deprivation. People with this disorder are often more alert and at their most productive at nighttime.

Advanced Sleep Phase Disorder

Usually seen in the elderly, this disorder is characterized by regular early evening bedtimes and early morning awakenings. People with this disorder usually complain of insomnia or sleepiness in the late afternoon or early evening.

Jet Lag

A conflict between the regular sleep/wake cycle and the internal biological clock occurs as the result of being in a new time zone. This can make it difficult to adjust and a person suffering from jet lag will feel fatigued during the day and alert at nighttime. Traveling east is far more difficult than going west because it is easier to delay sleep than advance it.

Shift Work Disorder

People who frequently work at different times of day or work at night experience a conflict between the body’s natural circadian rhythm and their work schedule. It can result in insomnia or excessive sleepiness due to the constant or recurrent interruption of sleep patterns.


This sleep disorder is marked by excessive daytime sleepiness and uncontrollable sleep episodes during the daytime in spite of adequate nighttime sleep.

Treatment for Circadian Rhythm Disorders

Options for treatment vary depending on the specific circadian rhythm disorder and the severity. Individualized treatment plans maximize the chance of success. Such options include:

Behavior Therapy

This type of therapy involves maintaining consistent sleep/wake times, avoiding naps, having an exercise program, avoiding caffeine and nicotine, and having a curfew for stimulating activities before bedtime. For delayed sleep phase syndrome, people should minimize exposure to light during their bedtime routine by reducing indoor illumination and avoiding light emitted from electronics such as TV, computers and cell phones. For advanced sleep phase syndrome, people should increase exposure to light in the evenings by keeping lights on longer.

Bright Light Therapy

Used to advance or delay sleep, this type of treatment requires guidance from a sleep specialist and particular attention to timing. A high intensity light is used and the duration and timing of the exposure can vary from one to two hours.


Medications may be used, such as melatonin, wake-promoting agents and sleep aids. These can be adjusted to maintain the sleep-wake cycle at the desired schedule. Melatonin is an over-the-counter sleep aid – it is a hormone that is particularly effective in treating jet lag.


In order to anticipate or cope with jet lag, a person should advance or delay their bedtime by one or two hours every day. Once the desired schedule is achieved, the sleep-wake cycle should be maintained.

If you are interested in finding out more about circadian rhythm disorders and how it may be affecting sleep quality, call The Los Angeles Sleep Study Institute at 1-855-690-0563 and one of our representatives will be happy to answer any of your questions.