The Various Stages of Sleep
11th February 2022Have you ever wondered why you sometimes wake up feeling more tired than before you went to bed or why you wake up to every little sound? Do you have days where you have to snooze your alarm clock 5 times before you are able to get out of bed? All of this has to do with the different stages of sleep you are in when you wake up. Herewith a breakdown of the stages of sleep.
REM and NREM
According to scientist these are the two main categories of Sleep. REM – Rapid Eye Movement and NREM – Non-Rapid Eye Movement. At the beginning of the night, you will experience a longer period of NREM sleep followed by a short period of REM sleep and as the night progresses you will have a shorter NREM sleep and the REM sleep increases. This nightly cycle should last between 90 and 110 minutes repeated around 4 – 6 times a night. Each state of sleep is characterised by different responses of the body, functions and brainwaves.
Stages of NREM Sleep:
Stage 1 – The first and lightest stage of sleep. This is where you start to drift off to sleep, getting sleepy, eyes closing and the mind growing quiet. You not in a deep enough sleep yet so any small disturbances can still awaken you. Your eye movements and breathing becomes slower, your muscles starts to release the tension of the day and relaxes which sometime can result in jerks or muscle spasms called hypnic myoclonia.
During the first stage your brain produces low frequency and high amplitude alpha and theta waves. The initial stages of stage 1 results in brain activity similar to that of someone who is awake and relaxed. Stage 1 takes 5 to 10 minutes. Brain activity in this stage is similar to someone who is relaxed and awake. Stage 1 takes 5 – 10 minutes.
Stage 2 – The stage of real sleep. Your heart rate and body temperature drops, putting you in a deeper sleep and it becomes slightly more difficult to be awake during this stage. Eye movement ceases and muscle relaxation and tone alternates. In this stage Theta waves still predominate but are interrupted by sleep spindles.
Sleep spindles, as well as K complexes are said to aid in the prevention of awakening. You spend Approximately 20 minutes in stage 2.
Stage 3 – You are now in a deep sleep. Waking up in this stage will leave you momentarily disoriented and confused.
There are 2 stages in stage 3 but are grouped together as they are both considered periods of SWS, slow wave sleep. Your brain activity slows down and high amplitude, very low-frequency delta waves predominate. Scientists claim that the higher your levels of alpha brain wave activity in your brain the less awake and refreshed you feel after waking up.
During this stage there is a further drop in blood pressure, your breathing deepens and you have virtually no muscle movement. The hormones that trigger growth and replenish fatigued muscles and target appetite control are released during this stage, which makes it a necessary stage to rejuvenate and reboot your body.
In this stage is where you will experience sleepwalking, night terrors and sleep talking. You will enter this stage 35 to 45 minutes after falling asleep.
REM Sleep – The Dream Stage
Due to the heightened cerebral activity that occurs this is the stage where intense dreaming takes place. You will have rapid eye movement. Your brain activity is high and resembles that of a person who is awake. This stage
An important part of REM sleep that you should be aware of is, that your heart rate and respiration increases drastically and your limbs and muscles undergo temporary paralysis. This restriction of movement stops your body from acting out your dreams and potentially injuring yourself. The term for REM sleep is paradoxical sleep this is due to the opposing states of low muscle tone and high brain activity. REM sleeps starts 90 minutes after you fall asleep and cycles around every 90 minutes. Babies spend 50% of their time sleeping in REM sleep where as adults only spend 20% of theirs in REM sleep.
The sleep cycle mentioned above might only consists of 4 stages but it is not a linear process. The cycle goes as follows: stages 1, 2 and 3, then it reverses back to stage 2, and only then do you enter REM sleep. Waking up can occur between stages or even during the stages when you change sleeping positions.
The different stages have unique characteristics and carries out various functions in the body. REM sleep is needed to keep your mind active and healthy. NREM sleep is needed to rejuvenate and refresh your body. all the stages are necessary for the sleep cycle to function effectively, skipping any of the 4 stages could have dire consequences.
Upon waking your heart rate and respiratory function returns back to normal so does your muscle movement. You re-enter consciousness and depending on how well you slept, you will feel ready to face yet another day.
Now that you know the stages of sleep it might be time for bed, Sleep well and sweet dreams.