From a standpoint of pure evolutionary survival, sleep seems like a pretty foolish activity. Lying prone and inactive for a third of the day means you’re not able to do all the things we’re designed to do. Such as feed, socialise and mate. It also make you especially vulnerable to predators.
Given the inherent risks to our health as a species that bedding down entails then, our body must have a very important reason to do so. Well, what is it?
To be honest, even after decades of research the exact reasons why our bodies are programmed for such a long periods of slumber is still something of a mystery to medical science.
Sleeping is detoxing
What we do know however is that skipping sleep is bad for your health. Really bad. Almost every single indicator shows that the less time we spend asleep, the worse our physical and mental health.
As a result one theory as to why we sleep that’s gained a lot of traction is the thought that sleep itself is a form of detox.
If you think about it this seems quite logical. When you’re lying comatose in bed you almost by definition can’t be doing anything harmful to yourself. This period of inactivity gives the body time to take stock, replenish and restore.
For instance, while you’re getting your doctor-recommended eight hours a night you obviously can’t be eating or drinking anything. This gives your poor overworked (and underappreciated) liver eight hours of downtime to rest and recover. It sure needs it!
Sleep is a detox for your brain
In a particularly interesting 2012 study conducted by a team at the University of Rochester Medical Center, it was determined just like the body has a lymphatic system that helps to protect us from infection and disease by draining away toxins, the brain has a ‘glymphatic system’.
The glymphatic system (so called because it’s managed by brain cells known as the glial cells), helps to clean away toxins and waste products responsible for brain diseases.
The same study found that the glymphatic system is almost ten times more active during the hours we are asleep than when we are awake. What’s more we’re slumbering the system seems to also be far more effective at removing one very important toxic protein in particular – amyloid-beta – which is fortunate for it’s believed this is the guy who has a huge role to play in Alzheimer’s.
Apparently while we are at rest our brain cells also shrink by incredible 60% in size, this nifty trick apparently allows more space between them for toxins to be flushed away.
The brain truly is a wonderful thing and sleep is the time when it detoxifies itself and prepares itself for the endeavours to come.
Related reading: More Sleep Is Critical For Brain Detoxification
Sleep versus stress
Cortisol is the hormone that triggers our fight or flight response. Whilst wonderful for keeping us alive when threatened by wild animals, it isn’t always the most helpful in today’s relatively predator free world.
Nowadays cortisol, also known as ‘the stress hormone’ is pretty much Public Enemy Number 1 when it comes to our health. When we worry about the bills, work or pretty much anything, our cortisol levels spike. Exercise is a great way to burn off this excess stress energy but unfortunately most of us lead a fairly sedentary desk or couch based lifestyle.
Not only does too much cortisol lead to anxiety, stress and ultimately depression. Elevated levels of the hormone have been linked to anything from poor memory, reduced immune function, poor bone density, increased weight gain, raised blood pressure, worse cholesterol and even heart attacks. The list goes on and on. The long and the sort of it is, more cortisol means a lower life expectancy and a more unhealthy and unhappy time.
Fortunately quality rest is the perfect antidote to stress. While we at rest our body is able to go on a stress detox and the levels of cortisol in our system are thankfully reduced to their lowest levels. The longer we spend asleep the more reprieve our body and mind get.
Well, there you go. While exercise and diet may be seen as the two pillars of a healthy life, quality sleep is the bedrock on which they sit. A whole host of very important processes take place while we’re at rest, if your sleep is broken or too short then these processes are interrupted or inefficient.
While medical science may not yet completely agree as to why we sleep, it’s fortunate for our body and mind we do, the down time allows our system to detox and prepare for the following day.
Author Bio: Hi, I’m Sarah from sunny California. When I’m not tucked up in bed getting my full eight hours, I spend most of my day researching and writing about sleep. My colleagues and I at the Sleep Advisor blog, fully believe a better night’s kip is the secret to a healthy and happy life. Thanks for reading and sweet dreams!