Your body runs on an invisible or internal clock that causes you to feel sleepier at night and more awake and alert during the day. This natural sleep-wake rhythm is known as the circadian rhythm. A disruption of this rhythm may be considered a circadian rhythm sleep disorder.
Disrupting this natural rhythm in the body can cause symptoms that range from daytime sleepiness to depression. Taking steps to get on a more regular sleep schedule can help.
There are several types of circadian rhythm sleep disorder. Many classifications are based on when a person typically goes to sleep.
Advanced Sleep Phase Disorder (ASP)
According to the American Academy of Sleep Medicine, an estimated 1 percent of the population experiences ASP (AASM, 2008). People with this condition go to bed earlier than most people—typically between 6 p.m. and 9 p.m. They also wake up early, usually between 2 a.m. and 5 a.m. People with ASP are more likely to be middle-aged or older adults.
Delayed Sleep Phase Disorder (DSP)
An estimated 7 to 16 percent of people have DSP (AASM, 2008). People with this condition typically go to sleep later than most people and sleep later, too. This condition is more common in adolescents and young adults.
Free-Running (Nonentrained) Type
Typically, people with this disorder have brains that do not recognize the lighting cues that signal circadian rhythms. They have varying, irregular sleep patterns. Dementia, blindness, or mental retardation can be contributing factors to this condition.
Irregular Sleep-Wake Rhythm
A person with this condition does not sleep for an extended period of time. Instead, he or she may take brief naps throughout the day. Symptoms include a chronic inability to sleep and/or excessive sleepiness. Neurological disorders, such as dementia, can contribute to this condition.
Jet Lag Disorder
This condition affects people of all ages and occurs when a person travels to another time zone. The body has difficulty adjusting to the new time. The greater the difference in the time zones is, the more significant the symptoms are. This condition is usually temporary, and it affects some people more than others.
Shift Work Disorder
This condition occurs in workers who work during the night or early morning hours. People with this condition have difficulty getting enough sleep in the daytime to compensate for lost overnight sleep.
Conditions that influence sleep include:
- levels of physical activity
- social activities
- levels of melatonin, a sleep hormone
Disruptions of one or more of these factors can lead to a circadian rhythm sleep disorder.
The pineal gland in the brain is responsible for releasing melatonin. Patients with disorders that affect the brain are more likely to have a circadian rhythm sleep disorder.
A circadian rhythm sleep disorder can impact many facets of a person’s life. Each disorder type has unique symptoms. Most people with circadian rhythm sleep disorders have one or more of these symptoms:
- difficulty going to sleep
- difficulty staying asleep
- not feeling refreshed after sleeping
Certain medical conditions can make a person more likely to experience a circadian rhythm sleep disorder. For example, people with congestive heart failure or chronic obstructive pulmonary disease are more likely to experience the condition. Additional risk factors related to medical conditions include:
- chronic pain syndromes
- mental retardation
Taking certain medications can stimulate the body and make sleep difficult. These include:
- beta-adrenergic drugs used to treat asthma
- selective serotonin reuptake inhibitors (SSRI)
People who travel overseas often are more likely to have a circadian rhythm sleep disorder. Evening shift workers are also at risk.
A sleep medicine specialist can diagnose a circadian rhythm sleep disorder. The specialist will typically recommend that you keep a sleep journal. This journal details when you went to sleep and woke up for one to two weeks.
People who have difficulties keeping an accurate sleep journal may opt for actigraphy. This technique uses a wrist monitor to measure periods of being awake and asleep.
A sleep medicine specialist may also recommend a sleep study. This involves sleeping under observation. A patient may wear a heart and/or breathing monitor during the sleep study. This helps a sleep medicine specialist rule out heart- or breathing-related sleep disruptions.
Addressing light and melatonin, the two chief factors affecting sleep, can help reduce circadian rhythm sleep disorders. A combination of changes to promote better sleep can help sufferers find relief.
Patients can purchase melatonin, a hormone that regulates sleep-wake cycles, over the counter to enhance sleep. This remedy is thought to be effective in treating jet lag.
A doctor may prescribe from a class of medications known as benzodiazepines for patients with acute insomnia. These medications work quickly, but insomnia can return when the medication is discontinued. Benzodiazepines are also known for being addictive. Examples include:
- quazepam (Doral)
- temazepam (Restoril)
- triazolam (Halcion)
Nonbenzodiazepine hypnotics are another class of medications that treat circadian rhythm sleep disorders. Unlike benzodiazepines, these medications are not addictive. They also do not cause a rebound effect, or a return of symptoms, after a patient stops taking the medication. Examples include:
- eszopiclone (Lunesta)
- zaleplon (Sonata)
- zolpidem (Ambien, Ambien CR, Edluar)
Patients with circadian rhythm sleep disorders often benefit from taking steps to make their bedrooms better suited to sleep. This includes:
- performing quiet activities, such as reading, before going to sleep
- avoiding bright lights at night
- sleeping in a quiet and comfortable room.
They should avoid stimulants such as caffeine, nicotine, and strenuous physical activity before bed. They should also avoid drinking alcohol, which can disrupt sleep.
Bright light therapy or turning on lights brighter than 2,500 lux for two hours in the morning after awakening has been shown to help those with DSP return to their more regular sleep rhythms (Dodson & Zee, 2010).
Circadian rhythm sleep disorders are not always problematic. While some people may not maintain a traditional sleep schedule, people with circadian rhythm sleep disorders may get enough sleep. For those that do not sleep enough, complications can include:
- disrupted social schedule
- trouble concentrating at work
If patients are able to make changes to their sleep routines and light exposure, they may likely resume a more normal sleep schedule. Others may need medications or altered work schedules to reduce symptoms.