Experts who specialize in sleep disorders and are employed in sleep labs regularly analyze the Phoenix karaoke of sleep and record their findings. These experts research such critical factors as brain wave activity, breathing patterns, muscle tension, eye movements and oxygen levels. Specialized equipment, such as an electroencephalograph, assist these professionals with obtaining this information.
The stages of sleep can be broken down into two broad categories: non-REM and REM sleep. Non-REM (rapid eye movement) sleep can be further broken down into four more stages – stages 1-4.
This first or beginning stage in the stages of sleep is aptly called Stage 1. During this phase, brain waves are markedly slowed and more relaxed. The beta waves are brief and quick, followed by the alpha waves, which are noticeably slower. It’s at this stage where you are just crossing over into sleep. Here, the activity in your muscles and your eyes start to slow down. This is also the stage that has been considered the transition phase between being awake and dozing off. If someone is abruptly awakened during this phase, he or she may not even be aware that they have drifted off.
Some individuals claim that during this phase, they have the sensation that they are falling and they may even experience hallucinations. While in this phase, you may also jerk and your startle reflex is heightened. Experts consider this phenomenon, known as hypnic myclonia or hypnic jerking, very common and no cause for alarm.
Next in the stages of sleep is, you guessed it, stage two. Here, our heart rate and body temperatures are reduced and brain wave activity is now quicker – referred to by experts as “sleep spindles”.
Moving into stage three of sleep, our brains go through a series of smaller, faster waves which are accompanied by considerably slower waves – what are referred to as delta waves. Moving through the stages of sleep to stage four, we now entering the deep sleep phase. During this stage of sleep, there is no eye movement or muscle activity. It’s in these last two stages – stages three and four, that children in particular may experience bedwetting, night terrors and even sleepwalking. If someone is awakened out of this stage, they will be foggy and it will take them a minute to “clear the sleep from their head”.
Following the first four stages of sleep is REM sleep. This is the last stage in our sleep cycle – the deepest stage which also lasts the longest. Each sleep phase is a slight bit deeper. This means that you are in each phase a little longer than the previous one. It’s in this stage – during REM sleep – that dreaming occurs and most of the recuperative functions associated with sleep take place.
Whether you’re a heavy or a light sleeper, dreaming is evidence that your brain is constantly at work. In this phase, our body temperature drops, blood pressure rises and our heart rate increases.