Understanding the different phases of sleep can help you prioritize healthy sleep habits and make informed choices for better rest.

Sleep isn't just a simple on/off switch; it's a fascinating four-phase rollercoaster known as the sleep cycle, with each phase offering unique benefits for your mind and body.

Sleep Phase 1: N1

It is the starting point for relaxation and going into sleep. Your brain waves slow down, your body relaxes, your muscles relax, and your heart rate starts to decrease.

This phase is brief, lasting only a few minutes, is less than 10% of your total sleep time, and you could easily be woken up during it.

Sleep Phase 2: N2

aka NREM2 or Light Sleep

This is when deeper slumber sets in. Your brain waves become even slower, and your body temperature starts to dip.

This phase takes up about 50% of your total sleep time, making it the longest stretch.

Sleep Phase 3: N3

aka Deep Sleep

This is the holy grail of high quality sleep. Your brain waves slow down dramatically, muscles become very relaxed, and your body focuses on repairing and restoring itself.

This phase is crucial for physical and mental health, but it makes up only about 20% of sleep in adults.

Sleep Phase 4: REM

aka Vivid Dreams

Finally, you reach a land of dreams! Your brain becomes super active, generating vivid dreams, while your body remains paralyzed (except for occasional eye movements).

This phase is essential for learning, memory consolidation, and emotional processing. It makes up around 20% of sleep in adults, with longer periods occurring towards the end of the night.

The Cycle Repeats

Impressively, throughout the night, you cycle through these sleep phases roughly every 90 minutes, with more REM sleep concentrated later in the night. So, this 4 phase cycle repeats through the night, albeit with different length of intervals.

At Seattle Oral Care, a sleep clinic, we believe that each sleep phase plays a vital role in overall sleep quality and contributes to your physical and mental well-being.