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In recent years, more and more people have realized the benefits of a good night’s sleep. There is a steady increase in the number of purchased sleeping accessories.
Thanks to sleep trackers, people are aware of the importance of the phases of the sleep cycle or the 5 sleep phases. It plays an important role in sleeping better and waking up refreshed.
Most people tend to divide the sleep cycle into the rapid eye movement (REM) cycle and the non-REM (NREM) cycle. But the NREM cycle itself has 4 stages of sleep. Sleep quality has a direct correlation with the amount of sleep you sleep in each sleep cycle.
REM and NREM sleep alternate. Normal sleep on any given night usually contains 4 to 6 sleep cycles. Each cycle usually lasts between 90 and 100 minutes. Subsequent sleep cycles have a longer REM sleep time, and the non-REM sleep time gradually decreases.
Let’s understand the 5 different stages of sleep in a more clear way.
What are the 5 Stages of Sleep?
Stage 1: Non-REM – Falling Asleep
This is the first stage of sleep that begins when you fall asleep. It is a light sleep period and you can easily wake up with even the slightest discomfort. The stage is really short-lived.
In phase 1
- The heart rate slows down.
- Body temperature drops.
- Breathing is slow and the muscles tend to relax.
Stage 2: Non-REM – Light Sleep
This phase lasts about 25 minutes with light sleep. Prepare the stage for a deep sleep.
In phase 2
- Breathing slows further and the heart rate stays lower.
- Negligible for any eye movement.
- The body temperature is low.
- There is an explosion of neural activity called sleep spindles.
Stage 3: Non-REM – Deep Sleep Phase 1
This is the stage where you fall deeply asleep. Stages 3 and 4 are crucial for the brain to relax and recover. There are multiple health-related activities that take place during deep sleep.
In phase 3
- Restores the body and promotes muscle growth in the body.
- Low bloodpressure
- It is very difficult to wake up from a deep sleep. When you wake up, you will feel disoriented and it may be
- difficult to go back to sleep.
- The brain wave slows down.
Stage 4: Non-REM – Deep Sleep Phase 2
At this stage, the body becomes even more immersed in sleep.
During phase 4
- Growth hormones are released.
- During this phase, tissue repair takes place.
- It is also responsible for strengthening the immune system.
- Delta waves are produced in the brain.
- In deep sleep there is no eye movement.
Stage 5: REM Sleep
After about 90 minutes, the body enters the rapid eye movement phase or REM sleep cycle. This is the stage where a human begins to dream that leads to eye movements. The first cycle of REM sleep is the shortest and increases with each cycle.
Again, it’s the shortest at the end of your sleep cycle.
During phase 5 of the REM cycle
- The respiratory rate is high and shallow.
- There is rapid eye movement.
- Blood pressure and heart rate are high.
- The limbs are almost paralyzed to avoid physical activity during dreams, but there may be mild spasms.
- Brainwave activity is high. There is a classification of information that results in learning and increased memory.