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The Sleep Cycle

Written by Lanna Wei

Sleep Cycles

Sleep is the most rewarding way to wind down, relaxing your body and mind after a long day at school or work. But have you ever wondered what exactly happens during these long hours? Normally, your body will process through 4-6 cycles, each one lasting around 90 minutes, but it could vary depending on factors such as age, alcohol/drug consumption, along with whether the person has a sleeping disorder (ex. insomnia).

For each cycle your body goes through during a night of sleep, you also transition through four different stages. The first three stages are known as non-REM (non-rapid-eye movement) sleep, and the higher the stage of non-REM sleep it is, the harder it is for someone to wake up because they’re in a deeper sleep. The final and last stage is known as REM sleep, named because this is the stage where your eyes rapidly move back and forth (creepy)! You typically transition into this stage after being asleep for at least 1.5 hours.

During the first cycle of the night, you transition slowly through all four of these stages in order, or chronologically. Afterwards, depending on your body, you might skip through certain stages and transition into deeper sleep. Everybody’s body changes through these stages and cycles during the night, and the pace or way it happens fits to adjust each person individually.

The Four Stages

Stage 1 Non-REM Sleep:

  • During the first stage of this sleep, your body and brain begin to slow down (along with twitches of movement) and shift from being awake to light dozing.

  • Usually lasting 5-10 minutes, a person left undisturbed will shift into Stage 2 of Non-REM sleep, however if awoken, it typically will feel like you haven’t slept at all.