Sleep, the Sleep–Wake Cycle and Sleep Deprivation

Purpose of sleep – evolutionary and restorative. Sleep–wake cycle as a circadian rhythm; three stages of NREM and one stage of REM, with characteristics (heart rate, eye movement, muscle tension, brainwave patterns via EEG) and the length/repetition of the sleep cycle. Sleep deprivation: causes (shift work, drugs, sleep environment, stressors) and effects of acute and chronic deprivation. Techniques to improve sleep hygiene (study: He et al., 2020).