Although our bodies are very still when we’re sleeping, there’s a whole hive of activity going on inside. For example, sleep is when our endocrine system - which makes hormones that control things like our metabolism and our mood - has its big moment. While we’re asleep, it increases production of the hormone Prolactin, which is vital for a healthy immune system. People who don’t get enough sleep have a much higher risk of suffering from things like diabetes, heart disease, depression, or even cancer because their bodies haven’t had the chance to produce enough prolactin to keep them healthy.

When you’re in the deepest cycle of sleep, your muscles are super relaxed - so more blood can flow into them and help the muscle tissue as it grows and repairs itself. This is also the phase of sleep where Somatotropin (the human growth hormone) is released and its job is cell reproduction and regeneration, so it’s pretty important in helping you grow and develop both physically and mentally.

When you make a new memory - when something happens to you, or when you learn a new skill or piece of information - that memory is quite vulnerable at first. In order for it to really stick it needs to be strengthened and solidified - it’s called ‘memory consolidation’. And it’s when we’re asleep that this happens most effectively. Sleep sparks changes in the brain that solidify memories, strengthening connections between brain cells and transferring information from one brain region to another to find the best place for memory storage.

You’ve got two main hormones in your body that help regulate your eating habits: Leptin and Ghrelin. Leptin tells your brain when you're full, so it knows to start burning up everything you’ve just eaten and turn the calories into energy, and ghrelin tells your brain when you need to eat and also when to stop burning calories and store energy as fat for your body to use later on. When you sleep, your leptin levels go up and your ghrelin levels go down - your body knows you have plenty of energy (as sleeping doesn’t require much!) so there's no need to trigger feelings of hunger. But when you don’t get enough sleep you get too much Ghrelin and not enough Leptin, which makes your brain think you don't have enough energy and you need to eat something. So not only do you pick up food that your body doesn’t really need, but all the calories get stored as fat instead of burnt!

Stefani Germanotta (Lady Gaga to us) is known for her slightly eccentric behaviour, like back in 2011 when she arrived at the Grammy Awards inside a giant egg which she then used for the performance of her hit single ‘Born This Way’. As if that wasn’t weird enough, it turns out she felt so at home inside the egg she then slept inside it for three nights.

Running England during World War Two, guiding the nation to victory alongside the allies and writing some of the most famous speeches in history was a fairly time-consuming job. So, with the help of a little whisky and soda, Churchill would nap for two hours every afternoon, allowing him to stay up and keep working all through the night. He did this almost every day he was in office (a total of 9 years, since he was Prime Minister twice) which means it’s a pretty big miracle he ended up living to be 90!

As the most decorated Olympian of all time, it’s no wonder Phelps goes further than most people to keep up his physical fitness. He sleeps every night inside a special chamber that simulates high-altitude atmospheric conditions because the lower levels of oxygen make his body work extra hard and that builds his endurance. Basically, he’s so hardcore he even trains in his sleep!

The master of surreal art was not a big fan of sleep. He thought it was a total waste of time and actually developed his own technique to make sure his body was never able to go into standby for more than a few minutes at a time. When having a rest he would sit with a key in his hand and place a metal plate on the floor, directly beneath his hand. As he started to nod off the key would fall from his fingers and clatter onto the plate, jolting Dali awake again. That strange melty clock is starting to make more sense now.

The sultan of the stepover has adopted a ‘polyphasic’ approach to sleep - which means instead of slumbering for the whole night like the rest of us do, he gets his Zzzzz’s in 90-minute naps throughout the day. This helps get around awkward match kick-off times and inevitable post-game adrenaline spikes that are common for top players. it also makes it easier for coaches to monitor and adapt Ronaldo’s sleep routine to make sure he’s always refreshed and match-ready.

Turns out the Real Slim Shady needs more than just shades on his windows to help him nod off. Mr Mathers needs total darkness to sleep and goes beyond black-out blinds, insisting that his windows are covered in tinfoil. Plus he finds it hard to sleep without white noise blaring through the TV and extra speakers in the room.