What is the relationship between early sleep cycles and non-REM sleep?

Early sleep cycles primarily consist of non-REM sleep, which includes several distinct stages. During the initial stages of sleep, a person transitions from light sleep to deeper stages. Non-REM sleep is characterized by slower brain waves and is divided into stages 1 through 4, with stages 3 and 4 being the deepest stages, often referred to as slow-wave sleep. This sleep is crucial for restorative processes in the body, including growth, healing, and supporting immune function.

In the early part of the night, non-REM sleep dominates the sleep cycle, typically taking up a larger portion of the overall sleep time before REM sleep becomes more prominent in later cycles. This is significant for understanding sleep architecture and the body's recovery processes during sleep. Therefore, the relationship between early sleep cycles and non-REM sleep is characterized by a predominance of non-REM stages, making this answer accurate and foundational to understanding sleep physiology.