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.
It’s important to note night terrors are not the same as nightmares. Whereas night terror episodes are usually forgotten by an individual, nightmares can be vivid and even recurring. This is because night terrors happen in the NREM sleep stage, while nightmares usually occur when a person is in REM sleep.
Night terrors most often happen in children who are aged 4 to 12 years old usually when they’re still in the first 3 to 4 hours of the night. Durations of episodes can vary, and can usually anywhere from 10 to 40 minutes.