We all know that if we want what we've studied during the day to stick, it's best to get a good night's sleep. And while scientists have long understood that our memories rely on connections being built between neurons in our brains, it's not been clear how sleep actually helps to consolidate that information.

Now, two new studies have found biological evidence that expains the age-old wisdom that if we want to remember, we need to sleep to forget.

It's natural that we're curious about why we fall unconscious for up to 16 hours every day. One recent hypothesis suggested that sleep flushes out potentially toxic proteins which build up in the brain during the day.

And recent studies have found that if we don't get enough sleep, we increase our risk of developing cardiovascular disease and type 2 diabetes, not to mention neurodegenerative disorders such as Parkinson's disease.