For a lot of people, getting to bed early is a real challenge. Every morning, you wake up feeling shattered and resolve to go to sleep earlier that day.

But then evening rolls round, the internet keeps distracting you (because of course, you simply must know which Hollywood hunk is your soulmate based on your pizza preferences), and before you know it it’s past midnight.

The latest Great British Bedtime Report from the Sleep Council found that 74 per cent of Brits get fewer than seven hours a night, and the number of people sleeping for fewer than five hours has grown from seven per cent to 12 per cent.

61 per cent of the 5,002 people surveyed in 2017 said between five to seven hours a night is the norm.

We all know how important sleep is - every day, new studies seem to find that sleeping longer will make us happier/thinner/richer/healthier/better.

But it’s also largely accepted that different people need different amounts of shut-eye - whilst some seem to fall apart if they get anything less than nine hours a night, others claim to function fine on four.

So how do you know what time to turn out the lights and hit the hay?

The trick is in fact not to worry about the length of time you sleep after all, but to focus on sleep cycles.

“The brain has a pattern of sleep. It’s not like you just fall asleep and hour one is the same as hours two and three and five and nine,” author and sleep expert Dr Laura Lefkowitz explained to the Telegraph.

“It goes through cycles. Within each there is what we call non-REM [Rapid Eye Movement] sleep, and then REM sleep.”

In pictures: End Youth Homelessness Sleep Out Show all 16 1 /16 In pictures: End Youth Homelessness Sleep Out In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of public attended the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Sadie Frost at the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of the public joined the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Seyi Obakin, the Chief Executive of Centrepoint, and Colin Salmon at the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of public attended the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of public attended the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of public attended the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Celebrities and 1,000 members of public attended the End Youth Homelessness Sleep Out in London's Greenwich Peninsula on 24 November Andy Barnes In pictures: End Youth Homelessness Sleep Out Lib Dem Leader Tim Farron gets ready to bed down as 1000 people get ready to sleep out for the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out The RAF prepare tasty food before a 100 people get ready to sleep out for the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out Independent reporter Alex Dymoke gets ready to bed down as 1000 people get ready to sleep out for the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out Anjali Patel, Remy Diamon-Ross and Hannah Kilminster join members of the RAF as they are given dinner Nigel Howard In pictures: End Youth Homelessness Sleep Out Bedding down for the night, sleepers get ready for lights out in one of several tents at the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out Bedding down for the night, sleepers get ready for lights out in one of several tents at the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out Bedding down for the night, sleepers get ready for lights out in one of several tents at the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard In pictures: End Youth Homelessness Sleep Out Colin Salmon is 'photo bombed' before he gets ready to bed down as 1000 people get ready to sleep out for the annual Centrepoint Sleep out at the Greenwich Peninsula Nigel Howard

In order to wake up feeling refreshed, you just need to make sure your alarm won’t go off mid-cycle - each cycle lasts about 90 minutes and ideally you should sleep through five or six.

“Waking up mid-cycle can leave you feeling grumpy and tired; rising in between phases will help you to start the day with a smile on your face,” Web Blinds say.

One way to find out what time you should go to bed is with their sleep calculator.

You enter the time you need to get up and they’ll give you an array of bedtime options. So if your alarm is set for 7.15am, they say you should go to bed at 10:01pm, 11:31pm, 1:01am or 2:31am.

The calculations are based on the fact that the average person takes 14 minutes to fall asleep, but of course this may not be the case for you.

Sleep-tracking apps are not new, but one of the best ways you can make sure you don’t wake up midway through a sleep-cycle is with a tracker such as Beddit, which accurately measures your sleep throughout the night with an unnoticeable strip of material that goes under your bedsheet.

Not only does the app analyse your sleep but you can also set the smart alarm to wake you up when you’ll feel most refreshed.