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Stages of the Sleep Cycle: Non-REM and REM


*Nothing in this article constitutes medical advice. Seek the guidance of a physician if you have any questions.*

Sleep is an essential part of our biological processes and is crucial to good health. We spend about one-third of our lives doing it, so it’s definitely not something to overlook! Sleeping helps our brains form necessary pathways and create memories. When we lack sleep our brains don’t function at the optimal level.

How much sleep do we need?

It is well established that adults should ideally get between 7 to 9 hours of sleep per night. There’s definitely no magic number, but most adults fall within this range. A chronic lack of sleep can result in a slew of health problems like high blood pressure, heart problems, obesity, and depression.

What are sleep mechanisms?

Humans have two internal sleep mechanisms that are designed to work together to regulate the sleep-wake cycle.

Circadian rhythm

Circadian rhythms are responsible for regulating numerous processes in the body from  temperature to wakefulness and hormone releases. When it comes to sleep, circadian rhythms use external cues like outside light and temperature to help regulate the sleep cycle.

Sleep-wake homeostasis

The homeostatic sleep drive is an integral part of the sleep-wake cycle. After each hour spent awake, the sleep drive strengthens throughout the day. The homeostatic sleep drive will remind the body to sleep after a certain period of time.

Workers with non-traditional schedules like night shift workers have disruptions in both their circadian rhythms and sleep-wake homeostasis. When these mechanisms are interrupted, healthy sleep becomes more difficult to achieve.

What are the stages of sleep?

We go through two primary phases of sleep – rapid eye movement (REM) and non-rapid eye movement (non-REM). The brain goes through certain activities during these phases, and cycles through each stage multiple times during the course of the night.

Here are the four stages of the sleep cycle:

Stage 1 (non-REM)

The first stage of sleep is a transition from wakefulness to sleep and is the lightest phase of them all, lasting only a few minutes. During this stage, heart rate, breathing frequency, and eye movements all start to decrease and the brain waves begin to slow.

Stage 2 (non-REM)

This is also a lighter stage of sleep that occurs before the deeper stages. The body and its processes relax even more. Brain activity slows while also having sporadic bursts of electrical activity. The body will spend more time in stage 2 than in any other stage during the sleep cycle.

Stage 3 (non-REM)

The final stage of non-REM is marked by slow brain waves. The body’s breathing and heart rate are at their lowest during stage 3. This period of sleep is essential for feeling refreshed in the morning, and generally occurs in longer periods during the initial part of the night.

Stage 4 (REM)

The first REM cycle is reached about 90 minutes after going to sleep. It is called “rapid eye movement” because the eyes will rapidly move under the eyelids. REM sleep is when dreaming occurs, and brain activity is more similar to that seen during wakeful periods. Breathing, heart rate, and blood pressure increase and can sometimes be irregular.

Sleep apnea and the sleep stages

In obstructive sleep apnea, the soft tissues in the throat relax and collapse, which prevents normal breathing from taking place. People who suffer from sleep apnea experience frequent disruptions in their sleep stages due to the body waking itself to resume regular breathing.

People who suffer from sleep apnea often experience excessive daytime sleepiness. A CPAP machine is the most successful method in treating sleep apnea and can help improve sleep quality significantly.

Properly cleaning a CPAP machine

Traditional methods of cleaning CPAP machine equipment can be tedious and time consuming. Instead of spending excess time using soap and water, there are other options that are much more effective.

Ozone cleaning is one of the best ways to sanitize CPAP equipment in the least amount of time. Ozone is a highly reactive gas composed of three oxygen atoms, and is a very potent cleaning agent.

The Sleep8 device is easy to use, and it disinfects CPAP equipment at the push of a button. How does it work exactly? Simply place any CPAP hoses, masks, and the water reservoir in the included bag, attach to the Sleep8 device and turn it on! It’s that simple.

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Written by Amanda Peterson


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