For me, sleep is one of the most fascinating things about the brain.
What actually is sleep? Why do we need it? Why does it have to be for so long?
And perhaps the question I find most interesting of all: if sleep is so important, why does it seem so impractical?
From an evolutionary perspective, sleep puts us in a vulnerable position. We spend around a third of our lives unconscious and unaware of what’s going on around us. Surely we’d be far more productive if we didn’t need it at all?
Understanding why your brain needs sleep can help us understand why poor sleep affects so many areas of our physical and mental wellbeing.
Yet despite millions of years of evolution, the need for sleep remains. In fact, it turns out sleep is so important that our brains simply can’t function properly without it.
What happens during deep sleep?
Very broadly speaking, there are two main types of sleep: REM (Rapid Eye Movement) sleep, which is the part of sleep where our brain is most active and dreaming occurs, and NREM (Non-Rapid Eye Movement) sleep, which is where we should be spending the majority of our sleep.
The purpose of NREM sleep is to allow the body to slow down and restore itself. During deep sleep, the body releases growth hormone and carries out many of its important maintenance tasks. I often think of it like taking your car into the garage for a service. This is when the body gets a chance to check over anything that needs repairing.
During this time, tissue, muscle and bone repair can take place. NREM sleep also plays an important role in regulating hormones, supporting the immune system and helping us wake feeling physically refreshed. Without enough deep sleep, it’s common to wake up feeling as though you’ve barely slept at all, even if you’ve spent plenty of hours in bed.
But whilst NREM sleep is largely responsible for helping the body recover and restore itself, REM sleep serves a very different purpose altogether.
REM sleep is the part of sleep that fascinates me most.
A common misconception is that during sleep everything shuts down for the 6-8 hours you’re out, but the reality is far from it. Many people assume the brain is at its most active when it’s reading a story, doing some complex arithmetic, solving a puzzle. In reality, it’s most active during REM sleep, carrying out some of its most important processing work. Your body goes into atonia, which is a temporary paralysis of the muscles (except for muscles that control your eyes and breathing), this is so our brains can have all the focus they need. It also stops us acting out our dreams, to keep us safe.
This is the stage of sleep most closely associated with dreaming, and where dreams tend to be at their most vivid. This is because the brain is busy processing the thoughts, experiences and emotions that have built up throughout the day. Conversations, worries, frustrations, achievements, problems to solve, things we’ve seen, heard and experienced all build up. The brain is processing all the information it has gathered throughout the day, sorting through memories and making sense of all of our experiences.
REM is there to improve cognitive functions like learning, creativity, problem solving and memory, which is why our brains are so active in this stage. There’s a reason people say “sleep on it” – because it actually helps! Whilst we’re sleeping our brains can work through those problems, so in the morning you can wake with a fresh mind, ready to take on the day.
One way I often explain it is to imagine your brain as a giant filing system. Throughout the day, papers are being thrown onto your desk faster than you can organise them. REM sleep is when the brain finally gets the chance to start filing everything away into the correct place. It’s also thought to help reduce the emotional intensity attached to events, meaning we can wake up the next day feeling better able to cope with life’s challenges.
It’s quite incredible when you stop and think about it. We spend around a third of our lives asleep, yet during that time our bodies are repairing, restoring and maintaining themselves, whilst our brains are busy processing the events and emotions of the day.
Far from being wasted time, sleep is one of the most important things we do for both our physical and mental wellbeing.
But if sleep is so important, what happens when we don’t get enough of it?
That’s exactly what I’ll be exploring in my next blog.
Sleep Doesn’t Exist in Isolation
If you’re struggling with sleep problems, insomnia or a busy mind that won’t switch off, you can learn more about my Sleep Problems & Insomnia Support service here.
Sleep also doesn’t exist in isolation. Factors such as stress, overwhelm and changes to routine can all have a significant impact on the quality of our sleep. In my previous blog, When School Holidays Throw Routine Out the Window, I talked about how changes in routine can affect our mental wellbeing and why finding moments of rest and regulation can be so important.
As a Solution Focused Hypnotherapist, I often see the impact poor sleep can have on both physical and mental wellbeing. Many clients are surprised by how much better they feel once their sleep starts to improve.