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The four stages of sleep and their importance from your Denver physical therapist

January 24, 2022

Everything accomplished in a day is possible because of the sleep achieved the night before. Some of the major systems that keep us alive, our respiratory, cardiovascular, and digestive systems to name a few, are impacted by the amount of sleep we receive. When recovering from a sports injury the body and mind need time to rest and recover as well.

Sleep is not one thing, rather four stages that cycle to form what most consider to be sleep. Within these four stages our bodies are able to repair themselves from the previous day's labors and prepare us for the day ahead. Whether for an athlete searching for the best route to recovery or someone interested in living their healthiest life, sleep is of the utmost importance. Here is some information on all four stages of the sleep cycle and why they are critical to our daily functions.

acronyms to know
NREM: non-rapid eye movement, also called quiet sleep
REM: rapid eye movement, otherwise known as active or paradoxical sleep 

The Stages

NREM Stage 1

The beginning of sleep. In the NREM Stage 1 you transition from being awake to sleeping, this all usually lasts about five to ten minutes. While in stage 1 your brain begins to slow and with it follow your eyes’ movement, heartbeat, and breathing. 

NREM Stage 2

In NREM Stage 2 you become less aware of your surroundings and eye movement completely stops. As your breathing and heart rate even out, body temperature drops and the brain begins to produce sleep spindles. They are believed to be associated with memory consolidation, which is the creation of memories through gathering, processing, and filtering the previous day. Lasting about 20 minutes, this stage is a preparatory for those to follow..

NREM Stage 3

NREM Stage 3 is the most restful of all the stages; your muscles are relaxed fully, breathing slows and blood pressure drops. This is where we experience our deepest sleep; also known as delta sleep. Our brain waves slow, becoming delta waves and while in this stage it is very hard to be awakened. The body takes this tranquil time to begin its physical repairs and the brain consolidates declarative memories, things you have learned throughout the day, general knowledge, personal experiences and such. NREM Stage 3 is the key to us feeling rested and ready for the day to come.

REM Sleep

Before coming into REM sleep, you first dip back into the preparatory NREM Stage 2 rest. Stage 2 accounts for about half of all the time we spend sleeping as it is a transition stage between others. After our bodies have gone dormant, the brain wakes up. Our breathing and eye movements are sped up and irregular, on scans the brain is lit up with activity. This can also be attributed to the fact that while in REM sleep, we experience dreams. 

Cycling through the stages is how our bodies are able to fully rest. Now that we have covered each, you can see that sleep is critical to our body's overall functioning. After completing one sleep cycle, it begins again allowing us to recover from injuries and daily strain. We here at Peak Physical Therapy and Wellness want to help you live your healthiest life and get back to playing your sport as soon as possible! Reach out today for an appointment and let us help you begin your journey through recovery.