You may think of sleeping as being a time when your mind and body ‘shut off’ but this is far from the case. Sleep is very active when we look at it through the lens of physiology. When you sleep, your brain cycles through different stages of sleep – from stage 1 (sometimes called transition sleep), into stage 2 (usually where most sleep time is spent) and in time will cycle into Slow Wave Sleep (or deep sleep). The final stage is called REM sleep. This stage is when you dream. Slow Wave Sleep and REM sleep are quite important and studies suggest they serve quite different functions. Slow Wave Sleep has been referred to as restorative sleep, because of the physical and mental restorative functions that occur in this stage of sleep. When we don’t get enough Slow Wave Sleep, or miss out on it altogether, the restorative effects of this sleep stage are lost.
REM sleep has been linked to memory consolidation and organisation. What this means is that during this stage of sleep, our brains organise, sort, clean and link different memories together so that when we operate during the day we are thinking clearly. Missing out on too much REM has been shown to make us feel as if our mind is ‘foggy’. In fact sleeping is so integral to our overall health, it is seen as the third pillar to good health, alongside diet and exercise. Getting a good amount of quality sleep allows us to perform and feel our best during the day. As such, getting not enough or even too much sleep, or not getting good quality sleep can significantly impact our daily performance, mood, energy, concentration, endurance and not to mention our overall physical health.