In my previous post on sleep, I talked about how to get a good night’s sleep and suggested some handy smart technologies we can use to track the patterns of our sleep and make sure we are, in fact, sleeping well.
But why is sleep so important?
Let’s start by saying sleep is something extremely complex, a lot more complex than we’d think. And it must be, otherwise ⅓ of our life (this is how much time we spend asleep) would be a complete waste of time. The truth is that sleep is a fundamental part of our biology.
Unlike most of us believe, there is a lot going on while we are unconscious; some parts of our brain are even more active while we are asleep than during the awake state. It’s precisely its complexity and how little we know about it that makes sleep a much fascinating state.
Sleep seems to be responsible for muscle recovery, restoration of the immune system and some interesting brain functions such as brain processing and memory retention. This is impressive, considering we, in the meantime, are peacefully (or not so peacefully) wandering the deepest areas of our dreams.
Researchers have identified 5 sleep phases, that alternate in a cycle throughout our sleep, with the 3 main ones being light sleep, deep sleep and REM. Each phase counts towards how fresh and rested we feel the next morning, but it is during deep sleep and REM that our body and brain experience the greatest benefits of sleeping.
Deep sleep is the deepest and most restorative phase. Our muscles are relaxed, blood pressure drops and breathing slows down. In this phase, our body releases growth hormones that help muscle tissue and immune system recovery. Meanwhile, our brain replays short term memory in the hippocampus.
We enter REM (rapid eye movement) sleep about 90 min after falling asleep and we re-enter it about 90 min later, with its length extending as we re-enter this phase (20-25% of our sleep). This phase is characterised by rapid eye movements and almost total temporary paralysis of the muscles due to the inactivity of monoamines (neurotransmitters responsible for stimulating motor neurons). When in REM sleep, short-term memory is transferred to the area where long-term memory is stored, therefore consolidating this memory. This is not all; in fact, it seems that REM sleep facilitates creative thinking and problem solving.
So don’t be surprised if, when you wake up from a good night’s sleep, you feel relaxed, focused, full of energy and perhaps you even realise you’ve just found a solution to a very complex problem or you’ve come up with a brilliant idea.
It is clear that sleep is not to be treated as a 'waste of time' or a gift to ourselves after a long day at work. Sleep is needed, as much as food is, to keep our mind and body sharp and healthy.