What Is Sleep Architecture?

Sleep Architecture Is Impacted By Age, Disorders

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If you have ever been curious about the structure of your sleep, and how sleep unfolds throughout the evening, you may want to learn about a concept called sleep architecture. Much like regular architecture, sleep architecture refers to the way that sleep is well, built. The idea of sleep architecture helps us to understand the pattern of the various stages of sleep, how these sleep patterns change as we get older, and what impact sleep disorders may have on sleep architecture.

 

Defining Sleep Architecture

Sleep architecture represents the cyclical pattern of sleep as it shifts between the different sleep stages, including non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Sleep architecture allows us to produce a picture of what our sleep looks like over the course of a night, taking into account various depths of sleep as well as arousal to wakefulness. Sleep architecture can be represented by a graph called a hypnogram.

There are generally four to five different sleep cycles during a given night and each of the different cycles lasts from about 90 to 120 minutes. Early in the night, you may transition from lighter sleep stages (called N1 sleep) to deeper, slow-wave sleep (called N2 and N3 sleep). REM sleep may appear, and it becomes more common during the latter part of the night, alternating with N2 sleep. REM sleep, also known as Rapid Eye Movement sleep, is the deepest state of sleep.

REM sleep is the state of sleep where dreams occur. Consistent interruptions to REM sleep can lead to a host of potential issues, such as sleep paralysis

How Sleep Architecture Changes with Age

Like many other aspects of life, sleep architecture alters with age. Have you ever held elderly people complain of difficult sleeping?

Well, there is a reason for it. As we get older, both the amount and the quality of our sleep may change. Slow-wave sleep often decreases as we get older and lighter N1 sleep increases. As a result of this shift, it becomes easier to awaken throughout the night and harder to fall, and stay asleep at night. As a result, more time may be spent awake, leading to insomnia, and a host of other potential problems. Often, people are then forced to take naps during the day in order to make up for lost sleep. 

The Impact of Sleep Disorders on Sleep Architecture

Certain sleep disorders may also have an impact on sleep architecture. There are certain sleep architecture abnormalities that may exist in the context of sleep disorders. If REM sleep occurs earlier than 90 to 120 minutes into the sleep cycle, this may suggest various causes, including:

  • Narcolepsy: An individual with narcolepsy might fall into a deep REM sleep at a rate much quicker than normal. 
  • Irregular sleep-wake rhythm
  • Withdrawal from tricyclic antidepressants or MAO inhibitors

Other sleep disorders such as sleep apnea may lead to disruptions of the natural sleep architecture with frequent arousals leading to numerous sleep stage shifts and abnormal cycling of sleep.

Sources:

American Academy of Sleep Medicine. "International classification of sleep disorders: Diagnostic and coding manual." 2nd ed. 2005.

Hirshkowitz, M. et al. "Polysomnography of adults and elderly: sleep architecture, respiration, and leg movement." J Clin Neurophysiol. 1992 Jan;9(1):56-62.

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