We're forever being told to get our 'eight hours' of shut-eye a night - but how much sleep do we really need? Research suggests that individuals have different requirements when it comes to sleep - while some of us can function on just six hours, others need a good nine hours to feel well rested.
Top sleep searches:
What's more, the amount of sleep we need changes over the years, and according to the experts, is different for men and women. So are you getting the shut-eye you need?
Teenagers really do need more sleep
If you live with teenagers, you'll know that getting them out of bed in the morning isn't always an easy task. Are they just being lazy or do they actually need that lie-in? Research suggests that they need more shut-eye than children and adults due to a growth hormone which is only released while they are asleep.
Older people don't need less sleep
You might think that we naturally need less sleep as we get older, but research suggests this is a myth. In fact, older adults need just as much rest as the young but, because they often find it harder to sleep soundly, they can misinterpret this as a sign that they don't need so much.
Although the quality of sleep may suffer as we age, it's important to try and get a good amount of shut-eye in order to avoid memory loss associated with ageing.
Bed sharing a 'brain drain' for the boys
As nice as it is to cuddle up with your loved one as you drift off to sleep, sharing a bed isn't always a good idea for men.
Researchers in Austria found that men were less able to sleep deeply with their partner than women. This resulted in rising stress hormone levels and the boys' ability to perform a simple cognitive test suffered. It also explains why your man might be grumpy in the morning!
Women need more sleep than men
In contrast it turns out that women need more sleep than men. A study at Loughborough University found that women are worn out from all that multi-tasking they're famous for, and need more sleep as a result - 20 minutes to be precise.
Everyone should take a siesta
Our European friends have long enjoyed a siesta but it seems we should adopt the habit too. Researchers in America found that having forty winks after lunch improves the brain's ability to absorb new information. The theory is that the hippocampus, which stores our short-term memory, gets full up during the morning's work and a siesta enables the brain to clear the facts it's already processed, thereby making way for new memories.