It's a commonly touted fact that we know more about the surface of the moon than we do about the depths of the ocean. But it's not just the deep blue sea which remains full of mystery...

The science of sleep may be constantly improving, but there's still an awful lot we don't know about those all-important 7-9 hours of shut eye which every human needs to function.

From why we dream, to the absolutely fundamental question of why we sleep at all.

Given that a 90-year-old human will have spent an average of 32 years asleep, it's incredible how little we understand about what happens in the Land of Nod.

But for every unanswered bedtime question, there are lots of fascinating facts which offer a glimpse into our sleeping bodies and brains. These discoveries shed some light on sleep, often highlighting just how fundamental the process is to our health and happiness.

Here are a few astonishing facts about sleep to blow your sleepy mind...

1. Older people are more likely to dream in black and white

A 2008 study by University of Dundee researcher Eva Murzyn revealed that older generations are more likely to report dreaming in black and white. Her findings suggest that television affects how we experience dreams. Those who grew up with black and white television more commonly reported black and white dreaming, while only 4.4% of under-25s interviewed reported monochrome dreams. Newer generations are far more likely to dream in technicolour.

2. Younger people experience more “hypnic jerks”

You know that sensation of tripping or falling which makes you jerk awake in your sleep, usually just before you've properly dropped off? These twitches are known as hypnic jerks and they happen all night, with the majority failing to wake you. Hypnic jerks are much more frequent in younger people. This study revealed that 8-12-year-olds experience an average of 4-7 hypnic jerks per hour, while 65-80-year-olds experience 1 or 2.

Why these jerks occur is still a bit of a mystery. Some claim they're the result of an old trigger in our minds designed to stop our ancestors falling out of trees while they slept. Other theories suggest that hypnic jerks occur just as our bodies are becoming paralysed by sleep and just as we start to dream. Because we're experiencing dreams before sleep paralysis kicks in, our bodies react to our dream actions, causing us to jerk.

3. Sleepwalking could be genetic

One in six children will sleepwalk in childhood, while one in 50 adults are sleepwalkers. Incredibly, 80% of sleepwalking adults claim to have a relative who is also a sleepwalker. In fact, Washington University's School of Medicine claim to have pinpointed the exact chromosome behind the condition.

4. Getting less sleep lowers your pain tolerance

According to this substantial study, individuals who suffer from insomnia or who have not received an adequate amount of sleep have a lower pain threshold than those who get their full 7-9 hours a night.

5. Our sleeping position really could reflect our personality

There may well be real science between those many articles which claim to offer insight into your personality based on your sleeping position. This study by Professor Chris Idzikowski suggests those who sleep in the foetal position really are tough on the outside by sensitive at heart, while “starfish sleepers”, who doze on their backs with their limbs splayed, are good listeners.

Does your sleeping position reflect your personality? Are you related to sleepwalkers? What colour are your dreams?

However you sleep – are you getting enough shut eye? Study after study reveals that not getting enough good quality sleep can seriously impact on your health and happiness. Our quality mattresses and comfortable beds help you build your perfect night's sleep, so you can have a more energised tomorrow. Explore our range to start your Better Sleep Journey today.