What is the Origin of NREM Sleep Cycles?

The term is foundational to polysomnography and sleep medicine, classifying sleep based on electroencephalogram (EEG) activity and eye movements. 'NREM' differentiates this quiescent phase from the more active REM phase.

What is the Mechanism of NREM Sleep Cycles?

During the NREM stages, particularly SWS, there is a profound decrease in metabolic rate and brain temperature, allowing for significant energy conservation and cellular repair. Crucially, the largest pulsatile release of Growth Hormone (GH) occurs during SWS, driving tissue repair, protein synthesis, and fat metabolism. The slow, synchronized brain waves facilitate the transfer of memories from the hippocampus to the cortex for long-term storage.

NREM Sleep Cycles

Meaning

NREM Sleep Cycles, or Non-Rapid Eye Movement sleep cycles, constitute approximately 75% of total sleep time and are characterized by three distinct stages (N1, N2, N3), culminating in slow-wave sleep (SWS), which is the deepest and most restorative phase. These cycles are vital for physical recovery, energy restoration, and the crucial consolidation of declarative memory. The integrity of these cycles is a clinical marker of sleep health.