The Stages of Sleep
To put it simply, sleep disorders are also called parasomnias. They can occur whenever a person enters specific stages of sleep or when a person is about to fall asleep or wake up. In order to understand parasomnias better, one must first understand the different stages of sleep.
The stages of sleep are classified according to the type of brain activity present during each particular stage. If you’ve ever felt tired even after getting a full 8 hours of slumber the night before, it means that you didn’t enter the restorative stage of sleep. Night terrors and sleep paralysis also occur in different stages of the sleep cycles.
The stages of sleep are categorized into two types, composed of four stages in total.
The first type is called non-rapid eye movement (NREM) sleep. It is composed of 3 stages namely:
- Stage 1 / N1: This stage is the shortest, and is best described as when a person is dozing off, about to fall into a deeper sleep.
- Stage 2 / N2: During this stage of sleep, the breathing slows down and the body’s temperature lowers. The brain isn’t as active as it was in the previous stage but will still have a bit of activity.
- Stage 3 / N3: This stage is best known as short-wave sleep (SWS) and the body enters a deep sleep. This stage is vital for memory and creativity.
The second type of sleep is called rapid eye movement (REM) sleep, and it is when the amount of brain activity is at its highest during sleep. During REM sleep, a person’s eyes usually move rapidly despite the body being completely at rest.
REM sleep is important for memory, learning, and other cognitive functions. In order for a person to feel well-rested, they must enter REM to make the most of out of sleep’s restorative benefits.
Night terrors, or sleep terrors, are a variety of parasomnia usually classified under arousal disorders. An arousal disorder does not necessarily mean that an individual will immediately wake up, but instead be partially awake from a very deep sleep. The transition from short-wave sleep to almost waking up can cause someone to become very confused, or in the case of night terrors, terrified and disoriented.
An individual experiencing a night terror may experience the following:
- Crying or screaming suddenly
- Sweating profusely
- Appear flushed
- Increase in heart rate
In some cases, people with night terrors may jolt up suddenly and start to scream at something with their eyes open. Despite appearing to be awake, they might not be able to respond normally because they’re not fully awake. If a person is currently having an episode of night terrors, consoling them might be futile or may lead to them becoming more agitated.