Importance of Sleep

Most sleep experts classify sleep in four stages. Your body will move in and out of those stages when you go to sleep. According to the National Library of Medicine the stages of sleep are as follows:

• Stage 1 – Is referred to as light sleep, This stage is believed to occupy 5% of your night’s sleep.
• Stage 2 – Is referred to as deeper non rem sleep but not the deepest level of non rem sleep. This state is believed to occupy 45% of your night’s sleep.
• Stage 3 – Is referred to as the deepest level of non rem sleep. This stage is believed to occupy 25% of your night’s sleep.
• Stage 4 – Is referred to as REM sleep. This stage is believed to occupy 25% of your night’s sleep.

What happens during each stage?

Stage 1 begins when more than 50% of the alpha waves are replaced with low-amplitude mixed frequency activity. Breathing is regular. This stage last about 1 to 5 minutes.

Stage 2 this is when your heart rate drops, your body temperature drops. This stage is where your synaptic plasticity is active. It is essential in memory consolidation. The first cycle of this stage last around 25 minutes but it tends to get longer as each successive cycle occurs.

Stage 3 is considered the deepest stage of sleep. It is typically most difficult to wake from this stage of sleep. If a person is awaken during this stage of sleep it is common to be groggy and mentally foggy for some time after waking. Of course the time of groggy/foggy varies but typically it last between 30 minutes and 1 hour. This is the stage of sleep where people grind their teeth, sleepwalk, and have night terrors. It is also the stage where the body does most of its repair to your muscles and brain.

Stage 4 is your REM (rapid eye movement) cycle of sleep. It is the cycle that you dream and often remember your dreams. During the REM cycle of your sleep it is similar to being awake. The difference is your breathing is usually more irregular and erratic. This stage is usually 90 minutes into sleeping and the first REM cycle will last about 10 minutes and the last cycle can be up to an hour.

RESOURCES:
National Library of Medicine, Physiology, Sleep Stages, Aakash K Patel, Vamsi Reddy, Karlie R Shumway, John F Araujo, January 26, 2024
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Kaiser Permanente, Stages of Sleep, Ignite Healthwise, LLC Staff, July 31, 2024
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Sleep Foundation, Stages of Sleep: What Happens in a Sleep Cycle, Eric Suni, Medically Reviewed Dr. Abhinar Singh, December 8, 2023
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Last viewed: 20250309