How much sleep do you actually need?

While eight hours is the magic number that comes to mind when we think about how much sleep we need each night, a new study has revealed how tired we really are depends on gender, age, and where we live.

Researchers also found Aussies to be among the best rested in the world.

The length of a good night’s sleep also changes throughout one’s life cycle, according to Flinders University Professor Michael Gradisar.

His study found differences in sleep durations shifted dramatically throughout adolescence, before stabilising around the time we hit 30-years-old.

How much sleep we really need depends on gender, age, and where we live, a new study has found. Source: Getty

“As sleep is a central element in functioning, health, and wellbeing, the reliable detection of sleep patterns is a key interest,” he said.

Professor Gradisar joined other researchers from South Australia’s Flinders University and the University of Helsinki to collaborate with Finnish company Polar to compare the sleeping habits of 17,335 people globally.

At 16 years of age, a night’s sleep was around 7 hours and 53 minutes, but for 30-year-olds that dropped down 24 minutes (to 7 hours and 29 minutes) the study found.

“In recent decades, there have been reports of delayed sleep in young people, characterised by very late bedtimes, and difficulties waking up in the morning at a socially-appropriate time,” Professor Gradisar said.

The study also found clear differences between females and males throughout adolescence and young adulthood, with females having longer sleeps and earlier bedtimes than males.

Oprah Winfrey says she functions on just five-and-a-half hours of sleep per night. Source: Leon Bennett / FilmMagic via Getty

Australians get the most sleep

The results also show geographic location as another key factor to determine sleep duration.

People in the Middle East, Asia, and Southern Europe are getting significantly less sleep compared to everyone else.

Young adults in Asia had the shortest sleep duration, of 6 hours and 30 minutes, followed by America and the Middle East reporting 6 hours and 40 minutes.

This is a stark contrast to the longest sleepers being Oceania – which includes Australia, New Zealand and some Polynesian countries like Fiji – where 7 hours and 14 minutes was the norm.

“So our findings suggest that cultural factors likely impinge upon the sleep opportunity of young people around the world,” Professor Gradisar said.

Some famous people survive on surprising amount of sleep

While Kevin Rudd was Australian Prime Minister, he was known to get by on as little as three hours of sleep a night.

Fellow politician Margaret Thatcher trained herself to sleep on just four hours a night, during her reign as Britain’s Prime Minister, due to her busy schedule.

Iconic talk show host Oprah Winfrey claims she functions “very well” on just five-and-a-half hours per night.

Hollywood star and former Calvin Klein model Mark Wahlberg gets seven hours of sleep each night, but his bedtime is a strict 7.30pm, followed by a 2.30am daily wake-up.

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