The Stages of Sleep

The Stages of Sleep

Sleep is divided into several stages that cycle throughout the night, affecting the quality of rest individuals receive. The four main stages of sleep are:

1. Stage 1 (NREM): This stage is the transition from wakefulness to sleep. It is a light sleep stage where individuals may feel drowsy.
2. Stage 2 (NREM): Stage 2 is a slightly deeper sleep where heart rate and body temperature decrease.
3. Stage 3 (NREM): Also known as slow-wave sleep, this stage is crucial for physical restoration and growth hormone release.
4. Stage 4 (NREM): The deepest stage of sleep, where the body repairs itself and strengthens the immune system.

During the night, individuals progress through these stages in a cyclical manner, with each cycle lasting around 90 minutes. The order of the stages may vary throughout the night, with more time typically spent in deep sleep earlier in the evening.

The quality of sleep is influenced by the time spent in each stage, with restorative deep sleep (stages 3 and 4) playing a vital role in physical recovery and overall well-being. Disturbances in these stages can lead to feelings of grogginess, difficulty concentrating, and may impact mood and cognitive function.