It used to be believed that sleep was nothing more than a physical and mental shut down – a kind of nothingness, where our brain had a good rest, while our body did the same. However in the 1950’s new theories began to emerge that gave us a clearer insight into what is actually happening when we sleep and it seems that we are more active than we might think.
The four stages of sleep
Since the first research was carried out, four stages of sleep have been identified and these are standard across all people experiencing normal sleep patterns. Anything that falls outside of these patterns is considered disordered sleep, such as insomnia. So, what are these sleep stages?
Stage 1: Light stage sleep
When you first settle down to sleep your brain will produce alpha and theta brain waves and your eye movements begin to slow. This lasts for just a few minutes and is that period of time when you experience a feeling of being half asleep, but still conscious and aware. During this period we also have an active thought pattern – with many random thoughts and ideas.
Stage 2: Fairly light stage sleep
The next stage is where you go into a light sleep. This would be the stage you want to get to if you are having a daytime nap. It is restorative, but not enough to make you feel weary. This stage varies in the length of time, but your brain has a frequency known as sleep spindles and the brain waves slow significantly.
Stage 3 & 4: Non-REM and REM Sleep
This stage of sleep involves two main sleep types – Non-REM (NREM) and REM. REM stands for Rapid Eye Movement and this, along with NREM indicates a deeper stage of sleep than the first two stages. If you were woken during stages 3 and 4 you would feel disorientated and very sleepy. Your body will cycle through these stages around 4 or 5 times in a night.
During NREM sleep your body is almost catatonic with no movement at all. This is an extremely deep sleep that encourages cell repair that improves our immunity and overall health. As we get older we have shorter cycles of NREM sleep and it is thought that the ageing of our cells is connected to this.
Around 90 minutes after we first fall asleep (and after we have passed through the first 3 stages) we enter REM sleep. The first nightly cycle may involve around 10 minutes of REM, but this increases as we approach the 4th and 5th cycle to reach around 1 hour of REM. During REM your brain will enter a period of high activity, with increased breathing and heart rate. During this stage you will be dreaming. Babies can spend 50% of their sleep in REM, while adults tend to get around 20%.
It is thought that NREM sleep is for body repair, while REM sleep is while our brains process information such as memories.
How the sleep stages relate to disordered sleep
If you suffer with difficulty sleeping or getting to sleep, you are unlikely to pass through these stages in the correct order and enough times throughout the night to get the most benefit.
Some people find that they simply cannot get to sleep in the first place, delaying the start of the sleep cycle by hours in some cases. The number of cycles may then be reduced to just 2 or 3 during the night.
For others, they may find that they wake mid-cycle due to various reasons. This could be outside influences such as young children or physical problems such as needing the bathroom. This can result in needing to start from stage one again, reducing the effectiveness of each cycle.
For others, they may find they never enter the deeper stages of sleep due to sleep apnea (where they are woken continuously) or because they cannot relax enough. In this case, they cycle through the light sleep stages, without getting the all important restorative sleep they need.
The Sleep Infuser is designed to restore the natural sleep cycle and to take the user through the stages as many times as possible throughout the night. It is easy to see why it important to go through these cycles as both our body and our brain needs to be restored via these stages.