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Overview of Sleep Disorders

Regularly getting a good night’s sleep is crucial to both physical and mental health. During the sleep state, the body restores itself and memories are processed, benefitting our overall energy, alertness, and clarity of mind. How much sleep we need depends on our age and lifestyle, though it is generally agreed that adults should get approximately eight hours of sleep per night (slightly less as they get older).

When our bodies sleep is defined in part by circadian rhythms, natural chemical processes that control our internal body clock. These patterns are normally tied to cycles of light, inducing sleepiness at night and waking us in the morning when it is light again. Melatonin, for example, is a hormone that induces sleepiness, lowers body temperature, and prepares the body for rest. Levels of melatonin naturally increase during the early evening as it begins to get dark, reach their peak in the middle of the night, and taper as morning arrives.

Despite the restful exterior of the sleep state, sleep is a dynamic, structured state of consciousness that progresses through several different stages with differing functions. The stages are defined by patterns of brain waves, muscle activity, and eye movements. During the early stages of light sleep, the muscles relax and the sleeper begins to drift from awareness of the conscious environment. The sleep gradually deepens, eliminating conscious awareness of the external environment until slow-wave sleep (SWS) is reached. The next phase is characterized by further changes to the brain waves, as well as rapid eye moments, and is thus dubbed rapid eye movement (REM) sleep. REM is also the stage of sleep where dreaming occurs. Following a period of REM sleep, the brain returns to SWS, continuing to cycle through the sleep phases throughout the night.

Sleep studies have shown that each of these phases is important for a satisfying night’s sleep. Disorders that prevent or interrupt the stages of sleep can cause a significant amount of physical and emotional distress, as a person never receives proper rest and rejuvenation.

Common Sleep Disorders

The most common sleep disorder is insomnia, in which a person has difficulties either falling asleep or staying asleep. Insomnia can sometimes lead to sleep state misperception, a condition where even if the patient does go through all the stage of healthy sleep, they do not properly sense that they have done so and thus continue to feel sleep deprived. Insomnia may be a short term phenomenon, related to stress, environmental noise or temperature, or medication side effects. Jet lag is also a form of transient insomnia that travelers experience as their body clock readjusts to a new sleep schedule as they shift time zones. If the inability to sleep is frequent and lasts for a month or more, this can be classified as chronic insomnia. Chronic insomnia is a more complicated disorder, often caused by a combination of both physical and mental health factors.

Sleep apnea is a disorder in which breathing is interrupted during sleep, often accompanied by loud snoring. The momentary lapses in breathing can last up to ten seconds, sometimes waking the sleeper briefly, though they may have no memory of it. In more serious cases, sufferers of sleep apnea may have hundreds of these episodes per night, drastically reducing the quality of their sleep. Sleep apnea episodes may either be due to a momentary physical narrowing of the airway or an issue with signaling from the brain that tells the body to breath.

There are also several sleep disorders related to involuntary physical movements made during sleep. In the early stages of falling asleep, some people are woken by sleep starts, sudden muscle jerks sometimes accompanied by a feeling of falling. Periodic limb movement disorder is characterized by muscle spasms in the legs that can wake the sleeper. Restless legs syndrome is a similar phenomenon in which the sleeper feels cramping or other uncomfortable sensations in their legs that cause an irresistible urge to move them. In cases of REM sleep behavior disorder, the sleeper physically acts out the movements they are dreaming during REM sleep, which can sometimes be very physical or violent. It is a common misconception that people who are sleepwalking are acting out dream activities, but these episodes usually happen during SWS, before the dream stage of sleep.

Narcolepsy is a disorder that disturbs the waking hours of the sleeper, causing them to be overwhelmingly tired and sometimes fall asleep suddenly or at inappropriate times. Narcoleptics may also experience cataplexy, a sudden limpness or paralysis of the muscles in the body.

Risk Factors of Sleep Disorders

Short term sleep disorders pose no risk, as they usually pass in a matter of days, and the person is able to catch up on rest after a few nights of good sleep. Chronic insomnia, however, can cause significant sleep debt. A large sleep debt can cause physical, mental, and emotional fatigue, reduce alertness, and leave a person in a mental haze. Chronic sleep disorders can also put a person at risk for depression, which further exacerbates the sleep symptoms, extending the cycle of insomnia.

Next Steps:

While you may find this medical information useful, as the next step we strongly recommend that you make an appointment to see one of our physicians to ensure that your health issues are properly addressed.

To schedule an appointment with our physicians, please call our patient coordinator at 1-212-679-9667, send the form below or an email to: info@patientsmedical.com. We are currently accepting new patients and look forward to being of assistance.

We are located at: Patients Medical PC, 800 Second Avenue, Suite 900 (Between 42nd & 43rd Street), Manhattan, NYC, New York, NY 10017.



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Article Last Updated: 08/26/2015