Well, you already know that a minimum of 7 – 8 hours of sleep is imperative for good health. But what happens really during your sleep?
Our sleep is basically divided into two stages – REM (Rapid Eye Movement) Stage & Non-REM Stage!
Non REM Cycle – As we begin to sleep, we start with the Non-REM stage which typically lasts up to 90 mins. Non-REM sleep itself is divided across 4 stages. As we move from stage 1 to stage 4, we fall into a deeper sleep, the heartbeat and breathing slow down, muscles become relaxed. Delta brain wave (patterns of neural activity in the central nervous system) which is a slower (lower frequency) and high amplitude waves are produced by the brain during this time.
REM Cycle – start nearly 90 mins after falling into the sleep. In this time, our eyes move rapidly from side to side behind the closed eyelids. Brain wave activity becomes closer to that seen in wakefulness and the breathing becomes faster and irregular. The heart rate and blood pressure also increase to near waking levels. Most of our dreaming occur during this REM sleep. Our body temporarily paralyses the arms and legs muscles during this time – just to make sure that we do not act physically on the dreams!
The body switches between Non REM & REM cycle, with the length of REM cycle increasing in each stage. In normal sleep, the REM cycle can go up to an hour!
A lot of questions related to the sleep is still not fully answered by the scientific community. However, it is proven that inadequate sleep enough can create a lot of issues ranging from heart diseases, stroke, diabetes, high stress, depression, etc. Our body gets into repair mode during the sleep, as the HGH (Human growth hormone) secretion, which is important for repairing and building tissues is at its peak.
In short, a good sleep not only has a positive physical impact, it has a positive psychological impact too!