puhketsüklid

Puhketsüklid, also known as sleep cycles, refer to the repetitive patterns of sleep stages that humans and many other animals pass through during a night's sleep. These cycles typically last about 90 to 110 minutes and occur multiple times throughout sleeping hours. Each cycle consists of several stages, including non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep.

NREM sleep is subdivided into three stages: N1 (light sleep), N2 (moderate sleep), and N3 (deep sleep or slow-wave sleep). During these phases, the body experiences physical relaxation, reduced heart rate, and decreased brain activity. REM sleep, characterized by rapid eye movements, increased brain activity, and vivid dreaming, usually occurs towards the latter part of each cycle.

The structure of sleep cycles is crucial for restorative processes, memory consolidation, and overall health. In a typical sleep cycle, NREM sleep predominates at the beginning of the night, with deep sleep (N3) being most prominent early on. As sleep progresses, REM stages increase in duration, particularly in the later cycles, facilitating cognitive functions.

Disruptions to normal sleep cycles, such as those caused by sleep disorders, shift work, or travel across time zones, can adversely affect physical and mental health. Understanding and maintaining healthy sleep cycles are important for well-being, cognitive performance, and emotional regulation.

Research indicates that the sleep cycle pattern varies across individuals and age groups, with infants experiencing more REM sleep and older adults often experiencing less deep sleep. Overall, the integrity of these cycles is essential for a balanced and restorative sleep experience.