Before we answer the question why we need sleep, lets first define what sleep actually is. So what is sleep? The Oxford English Dictionary defines sleep as:
“a regularly recurring condition of body and mind in which the nervous system is inactive, the eyes closed, the postural muscles relaxed, and consciousness practically suspended”
So basically, it’s a state we enter where the body shuts down and we slowly drift out of consciousness.
When you put it in terms like that, it seems like a very weird thing to happen. Imagine explaining this to an alien who had never heard of sleep before: “Well, every night we go to our own special places where we shut down and lose consciousness and then automatically get turned back on when it’s morning.”
Sleep is a very strange thing indeed, but do we need it? And what happens during sleep? Could future developments mean we don’t have to sleep as much, if at all?
Do we need sleep?
So do we need this sleep? One way to find out is to see how we cope without it. If we don’t get enough sleep, we start feeling the effects of sleep deprivation. These effects get progressively worse until we do get some sleep. If for some medical reason we lose the ability to sleep, like in the extremely rare sleep disorder Fatal Familial Insomnia, we eventually die from exhaustion.
So we need sleep to function, and without it, we couldn’t live. But different people need different amounts, and the amount we sleep changes with age.
Newborns need the most sleep. In fact they spend the most of the day sleeping, up to 18 hours. The required number of hours required for sleep gradually fades until we reach adulthood, where it stays at around 7 – 8 hours of sleep per night. These numbers are only averages though. Some people only need 4 – 5 hours sleep per night to feel fully refreshed. Essentially it’s down to genetics.
The amount of time you sleep doesn’t really mean much. What really counts is the quality of sleep you receive. Even if you sleep a full 9 hours, if you don’t enter into good quality deep sleep during that time, you’ll feel like you’ve been awake all night. The quality of sleep thankfully isn’t governed by genetics, but by your sleep habits, sleep environment and the regular timing of your sleep pattern.
Some sleep patterns aim to improve what’s called sleep efficiency. This is worked out by the quality of sleep you receive verses the amount of time spent sleeping. So the higher your sleep efficiency, the less time you’ll need to sleep to wake fully refreshed. Some polyphasic sleep patterns (multiple sleep and wake times) require just 3 hours sleep per day, simply because you spend more time in the deeper more refreshing stages of sleep and less in the lighter stages, increasing the quality of sleep.
Do animals need sleep?
It’s not just humans who need sleep, most animals need it to. But the way they sleep can be completely different to the way we humans do it, although the general process is pretty much the same.
I say most animals need sleep because some scientists believe that some fish who live in coral or ones that need to keep swimming to breath or animals that live in dark caves, may actually be able to escape sleep all together.
So if it’s possible for some animals to skip sleep, by examining these creatures and discovering how they can do it, could it one day be possible for humans to skip sleep also. If we could, insomnia would be a thing of the past. We sleep for a third of our lives. What could humans achieve with an third of extra time? What more could have Einstein or Newton discovered?
This isn’t the stuff of science fiction. Scientists have actually discovered a gene that if correctly altered, can reduce the amount of time needed for sleep from 7 – 8 hours to around 6. That may not be much, but it’s a start, and the hours would soon build up. So who knows, maybe our future selves would laugh at this idea of “sleep”.
What happens during sleep?
Right now, and certainly for the time being, sleep is something everyone needs. But why do we need it? What actually happens when we sleep?
There are a number of theories which can help answer that question, but the full picture of why we need sleep is still not fully understood.
Sleep, as a research area, was previously avoided by scientists. It was thought that sleep was like shutting down a computer, nothing happens until it is turned back on, so analysing people in this state would be pointless.
However, it was found that the brain is in fact pretty active when we are asleep. Lots of things are happening. So now we know this, sleep has become a hot topic of research.
Its like thinking the sky is a ceiling, there’s nothing up there but the top of the earth, that’s pretty boring. But then finding out that there’s actually more than meets the eye, and that there’s actually a lot happening above our heads, many new worlds exist in space just waiting to be explored.
What we know about sleep
So while we now know sleep is much more interesting than was first thought, there’s still a heck of a lot of catch up to do. There are a few things we do know about it.
Sleep helps the body heal itself. The body’s ability to heal wounds is dramatically reduced without good quality sleep.
Sleep also aids your body’s defences. It’s been found that a lack of sleep decreases the number of white blood cells, the fighters against illnesses.
The growth hormone is also effected. Its main secretion is when you’re asleep. So the less you sleep, the less the growth hormone will be released.
The inactivity of sleep gives your brain a perfect opportunity to process all the information that it has gathered from the day. This helps explain why children need more sleep than adults, as they explore their new world.
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So, at least for the time being, we all need sleep. Until we understand the ways of these magical fish, we may as well make the most of it, it’s a third of our life after all. By improving our sleep habits, sleep environment and sticking to a regular sleep pattern, we can all get the deep refreshing sleep we need.