Most of us feel sleep deprived at one stage or another.

Going out, work, study, food - we all have a lot on that gets in the way of our shut-eye from time to time but one family doctor has now claimed that we, as a nation, are seriously sleep deprived. "We often subjectively think we sleep less than we actually do but it would seem that this is near crisis epidemic proportions now," Dr Maura Finn told RTÉ Radio One's Today With Sean O'Rourke. "It would seem that 30 to 40 per cent of people have less sleep than they actually need and for an adult, just for instance, you really should be getting 7-9 hours sleep." Sleep is an essential element of a healthy lifestyle, according to Dr Maura Finn. "It’s not good for our systems (to miss out on sleep) because during our sleeping times, especially if we go through the proper cycling of sleep, we actually lay down memories, we improve our immune systems, we modify our emotions. "It is actually essential for our basic health. Over the centuries, our sleeping patterns have dis-improved, probably since industrial times and the advent of artificial light really. But it’s getting worse and worse and it is affecting our long-term health." So how do you know if you're actually sleep deprived? There's actually a simple way to find out, thanks to a BBC programme called 'The Truth About Sleep'. You can take what's called the 'sleep onset latency test'. It's a quick test you take at home in the middle of the afternoon and all you need is a watch (although we'd use a timer), a metal spoon and a metal tray. You simply set a metal tray down next to your bed and lie on the bed, holding the spoon out over the side of the bed. Check the time (or set your timer) and then close you eyes and see how long it takes you to get to sleep. As soon as you fall asleep, your hand will release the spoon, dropping it on the tray and waking you up. When you wake up, check how long it took you to fall asleep. If it takes you fewer than 10 minutes to fall asleep in the afternoon, you're sleep deprived. If it's less than five minutes, you may have severe sleep deprivation.