User:Cancername/WIP/Sleep basics
Activity and alertness is reduced during sleep. While sleep affects the entire body, it most strongly affects the nervous system. Many important bodily functions, like waste cleanup and memory processing are supported by sleep. There are two kinds of sleep: rapid eye movement (REM) sleep and non-REM sleep. Non-REM Sleep has stages, which start at light sleep and progressively get deeper. In REM sleep, the eyes move quickly. Notably, most dreams occur in it. NREM sleep stages are numbered from 1 to 3, from lighter to deeper. Stages repeat in cycles of around 90 minutes.
Measurement
Sleep originates in the brain. The brain communicates within itself using electrical signals, they can be measured using electroencephalography (EEG), where electrodes are attached to the scalp and the resulting signals are measured. Additionally, eye movement is an indicator of sleep, we can measure the electrical signals causing eye movements using electrooculography (EOG), which involves attaching electrodes around the eye. Finally, skeletal muscle movement can also be used to measure sleep, and by attaching electrodes to skeletal muscle, its activation can be measured as an electrical signal, this is called electromyography (EMG). Other tests are also performed, however, these three are most useful to distinguish sleep stages. Together, these methods are called polysomnography (PSG).
Brain waves
[figure out how to make that fancy image box] [list all the patterns with frequency ranges]
Stages
NREM1
Non-REM sleep stage 1, also called light sleep, is the lightest stage of sleep and comprises around 5% of total sleep time. It generally lasts around 1-5 minutes. In an EEG, In light sleep, the sleeper may be aware, and believe themselves to be awake. [source] [PSG characteristics] [notable events and happenings] [significance?] [vital?]
Cycles
These stages are arranged in repeating cycles, typically lasting around 90 minutes [variance?]. [what order of sleep stages?] [differences between consecutive sleep stages]
Effects and functions
[functions of sleep] [effects on particular conditions]
References
- "51. Sleep and Dreaming". Principles of neural science (5th ed.). New York: McGraw-Hill medical. 2013. ISBN 978-0-07-139011-8.
- Patel, Aakash K.; Reddy, Vamsi; Shumway, Karlie R.; Araujo, John F. (2025). "Physiology, Sleep Stages". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 30252388. Retrieved 2025-06-08.
