The science of sleep can be fuzzy and confusing at times. Researchers are still not sure what our brains are up to, why we dream, or what those dreams even mean. But there are some intriguing things we’ve learnt in recent years about our mind’s journey to the Land of Nod.

Here are 10 surprising facts from the BBC Future archive and elsewhere that shed some light on why we need a restful night’s sleep:

1. Familiar smells can help to form memories in your sleeping brain, improving your performance at simple learning tasks.

Read more: “How to learn while you sleep”

2. The body shudders people report as you fall asleep are surprisingly common, and harmless – they’re called hypnic jerks.

Read more: “Why your body jerks as you fall asleep”

3. One small study proposed that learning the didgeridoo aids sleep, perhaps because it strengthens breathing muscles.

Read more: “The dos and don’ts of restful sleep”

4. The most natural time to nap, based on our circadian rhythms, is between 2 and 4pm. But while napping later in the day is more restorative, getting some shuteye earlier on is more likely to boost your creativity.

Read more: “How to nap like a pro”

5. As we discovered earlier this week, a mutation in a gene called DEC2 might allow some people to sleep consistently for only four hours a night with no adverse physical effects….

Read more “The woman who barely sleeps”

6. …however, that’s probably not you. Less than 5% of people are natural short sleepers. Most people need eight hours, but around 30% of us get fewer than six per night.

Read more: “The sleep secrets of CEOs” (BBC Capital)