Sleep is a physiological process that your body needs on a regular basis to replenish the resources you exhaust during the day and perform the internal functions that keep your body running properly.
There are phases and stages of sleep, however, that require a lack of distractions or disruptions by external factors, including:
- Tobacco use
- Excessive coffee intake
- Alcohol abuse
In this article, we’ll take a look at the different stages of sleep and how to make sure you enjoy them.
What are the physical stages of sleep?
While your eyes are closed, there are clear electrical oscillations that can be seen on an electroencephalogram (EEG) at an alpha rate of 8-13 per second.
As the minutes go by, you can highlight the changes associated with each stage of sleep, according to your brain activity.
This is how scientists learn what we know today about sleep.
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How are the stages of sleep divided?
- This is the lightest stage of sleep. This is a short stage during which your brain can enter and leave a dream state, and it’s also very easy to wake up.
- In stage 1 sleep, you experience rapid eye movements or REM sleep, as your body’s muscles are slowing down.
- You are able to perceive auditory and sensorial stimuli. This stage is not very restorative, as it’s the minimum level of rest.
- You may experience sudden muscle contractions during this stage, as well. This is why people sometimes experience the sensation of falling: it’s your perception of going from stage 1 into stage 2 of sleep.
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- In the second stage of sleep, a pattern emerges in which your rapid eye movements stop and the dynamic brain waves slow down, leaving a single activity of fast brain waves.
- On the EEG, a pattern known as the sleep spindles begins to appear.
- Apart from those slow waves, this is the moment in which your body temperature, heart rate, and breathing begin to slow down.
- At this point, your nervous system blocks the sensory stimuli, making it almost impossible to receive information from outside.
- This can make it a very refreshing part of sleep, although it occurs in small doses.
- In this stage of sleep, you start having much slower brain wave activity than in the previous stage. These are the delta waves, which are interspersed with rapid but smaller waves.
- In this stage of sleep, a person usually remains for two to three minutes without eye movements and can be difficult to wake up.
- Sensory stimuli are completely blocked. When a person wakes up during this stage, they may feel disoriented and confused.
- During this period, there are no dream images, the blood pressure is lowered, and growth hormone production is increased.
- This stage is guided almost exclusively by delta waves. It is a state of deep, intense sleep from which it is much more difficult to wake up.
- There is no eye movement activity or muscle movement. It’s usually in this sleeping state when children wet the bed, sleepwalk, or experience night terrors.
- During this stage of deep sleep, dreams do not occur. It usually lasts around 20 minutes.
- Still, it is the stage that lets you know whether you got good sleep, or if it was not restorative enough.
How many stages of sleep occur during one night?
People usually switch between rapid eye movement or non-rapid eye movement sleep in periods that range from 70 to 100 minutes.
Rapid eye movement sleep typically lasts between 5 and 30 minutes, while the rest belongs to non-rapid eye movement.
Both cycles typically repeat every hour and a half throughout the night, and you typically experience between four and six cycles of rapid eye movement sleep.