Extract from ABC News
Humans haven't always expected to sleep for 8 hours straight. (Getty Images: TonyBaggett)
Deep in the French countryside a monastery bell rings out across the tree-covered hills. Just as it has for centuries.
It's 7:30pm and time for the monks to go to bed — at least for their first sleep of the night.
Just before midnight, the bell tolls again. They wake, gather in silence, greet each other with a nod, and chant psalms in a dimly lit church for a few hours.
Then it's time for "second sleep", which lasts until 6:45am, when the monks get up again for another day of meditation, study and work.
It's a routine that dates back to medieval times.
Some experts say this "biphasic" sleep pattern has an even longer history, and is still evident in remnants of traditional cultures around the world.
And there is evidence of other pre-industrial sleep patterns too.
Did Stone Age humans sleep longer than we did today? (Getty Images: Anton Petrus)
A handful of people who spent eight weeks in a Stone Age-like settlement without electricity or mobile phones, were found to go to bed early and sleep solidly for two hours longer than normal.
Then there's "siesta culture" where you have a long nap after lunch during the heat of the day and shave some time off your sleep at night.
"Sleep is extremely adaptable," says Leon Lack of the Adelaide Institute for Sleep Health at Flinders University.
"What we consider today as normal … is a relatively new societal habit and should not be considered the only healthy way to distribute sleep across the 24-hour period.
"It's only industrialisation that has forced people really to be awake for 16 or 17 hours straight and ... restricted their sleep into the night time only."
The culture of the siesta in the afternoon suits some environments. (Getty Images: Artur Debat)
And it's this modern culture that has been responsible for some of the most enduring myths about sleep, Professor Lack adds.
These beliefs create unrealistic expectations about sleep and cause us to worry about it more than we need to … something that can make sleep even more elusive.
Myth 1: Waking up in the night is abnormal
As your brain rollercoasters through 90-minute sleep cycles it's almost as active as when you are awake.
Even REM (rapid eye movement) sleep, where we have the most vivid dreams, has brainwave patterns that are almost the same as when we are awake — although luckily we're in a semi-paralysed state so we can't act out those flying dreams.
The industrial revolution and the widespread use of electric light transformed our expectations of sleep. (Getty Images: Rapeepong Puttakumwong)
While it's common for people to complain about having "broken" sleep, it's actually natural to wake up briefly through the night in the lighter phases of sleep, and experts like Professor Lack urge us not to fear this.
Traditionally, when we slept in family groups, these light phases of sleep could have helped us keep an eye out for threats.
"People would go to sleep at different times across the night. In deep sleep, we would be vulnerable but we're not alone, we have a family around," Professor Lack says.
And, he adds, having older family members around would be an advantage because they're even lighter sleepers and more likely to wake up in the night.
Having said that, too much time awake at night can be a problem, especially if that's the only time you have available to sleep.
Myth 2: We should all get eight hours sleep
While most of us need seven to nine hours sleep, with eight hours suiting the average adult, some people need less and others need more.
The best way to tell how many hours you need is to listen to your body, Professor Lack says.
If you wake up feeling refreshed, then you're probably getting enough sleep.
If on the other hand you wake up wishing you had more energy and motivation, you probably aren't.
In this case, Professor Lack suggests adding an hour of sleep a night for a week (with a consistent bedtime and wake time) and then see how you feel.
Importantly, it's not just the hours you get, but the quality of sleep, which can suffer especially if you have a sleep disorder. If you end up feeling tired no matter how long you spend in bed, see your doctor.
Myth 3: Getting up early is best
"Early to bed early to rise makes you healthy, wealthy and wise" is just one of numerous sayings that seem to suggest getting up at the crack of dawn, or even before, is best for humans.
But some people are biologically wired to be night owls. Their body clock runs "slow", says Professor Lack, and this makes them want to go to sleep later.
The challenge for them is they're living in a society where they are likely to have to get up early, which means they tend to be "under-slept", he says.
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Having enough sleep, and a regular sleep and wake time, is more important for good health than being an early bird — although you do need to calculate your bedtime based on the time you have to wake up.
If a night owl can't organise their life to get the sleep they need, they might be able to reset their body clock to an early bird schedule by exposing themselves to daylight earlier in the day.
Myth 4: You can 'bank' sleep for the coming week by getting extra on the weekend
While sleeping in on the weekends might help pay back a "sleep debt" from the previous week, experts like Professor Lack say you can't "bank" sleep in advance, despite suggestions by some studies that it might be possible.
If you miss any sleep during the week you need to make it up the following weekend, he says.
Sleeping in might feel necessary but getting up at the same time every morning is the best way to get regular good sleep. (Getty Images: Boy_Anupong)
And while sleeping in on the weekends can be bliss after a week of burning the candle at both ends, there's a catch.
The best sleep comes from having a regular sleep and wake time, where you get up at around the same time.
When you sleep in, you reduce your exposure to morning light, which is key to setting your body clock, and this in turn helps make you sleepy at the right time
And if you stay up late Friday and Saturday as well, the combined effect of the changes is likely to make it harder to get back into a good sleep and wake time routine for the working week.
"So, it's a vicious cycle," Professor Lack says.
Myth 5: You can train yourself to sleep less
Unlike building muscles or weaning yourself off caffeine, no matter how much you practice you can't train your body to cope with less sleep than it needs.
"It doesn't look like you can permanently change the amount of sleep that you need," Professor Lack says.
Napping has always been a part of human culture, although it might not always fit in a 9 to 5 world. (Getty Images: Jorisvo)
Getting less sleep than you need builds up a "sleep debt" that eventually needs to be repaid.
And if it's not repaid it will eventually have an impact on your ability to think and react quickly — regardless of whether you even feel sleepy.
And that could be quite dangerous.
Myth 6: Spend more time in bed if you're having trouble sleeping
If you're having trouble sleeping, spending more time in bed hoping for sleep won't necessarily help.
Especially if you lie in bed worrying about sleep.
"If a person becomes worried about the fact that they're awake or starts ruminating about something, then they will feel more fatigued the next day," Professor Lack says.
He suggests doing something relaxing (not doomscrolling on your phone) until you drift back to sleep.
But if your waking periods become a problem, seek help for insomnia from a sleep psychologist or try an online resource from the Sleep Health Foundation or the Australian Sleep Association.
One of the treatments for insomnia is called "sleep restriction" where you're not allowed to go to bed until you build up your "sleep pressure".
This means when you finally go to bed you are so sleepy you're less likely to wake up.
Having said that though, most people are likely to go to bed later than they should, Professor Lack says.
And in an age of binge watching that's not surprising.
Myth 7: Quick naps in the day don't help
It's true that short naps don't generally allow you to get deep sleep, but they can be useful in paying back some sleep debt.
Unfortunately, although humans have napped through history, short sleeps are just not that convenient in an industrialised society, Professor Lack says.
But, if you've had a late night and still need to wake up early, he says even 10 minutes of shut-eye during the afternoon can help see you through the day.
"There is something about switching from wakefulness for just a very brief period of time, which is very effective at rejuvenating."
It's best to avoid long naps too late in the day if you want to get to sleep at a reasonable hour.
But then again, if you have a big night coming up, a good deep sleep in the afternoon with some decent time to wake up afterwards could be just the trick.
Thanks to other sleep experts interviewed for this story: Dr John Lesku, La Trobe University, Dr Christopher Gordon, Macquarie University and Dr Delwyn Barlett from the Woolcock Institute of Medical Research.
For more sleep myths or to find out if cheese dreams are real listen to What the Rash? and subscribe to the podcast for more answers to the health questions everyone's asking.
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