How getting more than eight hours sleep HARMS your brain – and makes work harder the next day
Your weekend lie-in is doing nothing for you - you'd be much better off trying to get eight hours sleep every night
FEW things feel quite as good as going to bed knowing that you've got a long lie-in the next day.
However much you might think you need those extra few hours, you're actually better off waking up at your regular time.
Because the largest sleep study in the world has confirmed that getting too much sleep is just as bad for you as getting too little.
Scientists from the University of Western Ontario's Brain and Mind Institute have found that under seven hours a night severely impacted brain health - but that oversleeping isn't healthy either.
Unlike other recent studies, these neuroscientists say that regularly getting anything under seven hours is problematic.
According to The Sleep Council, 70 per cent of Brits now sleep for under seven hours a night, with the average person clocking six hours 19 minutes.
In the first stage of their research, neuroscientists surveyed 40,000 people about their sleeping habits before getting them to do a series of cognition quizzes.
The tests measured language skills, reasoning and short-term memory.
While memory more or less stayed the same regardless of sleeping times, researchers found that language skills and reasoning were deeply affected by the amount of sleep participants were getting.
The golden amount of time for high brain performance, regardless of age, was seven to eight hours every night.
“We found that the optimum amount of sleep to keep your brain performing its best is 7 to 8 hours every night and that corresponds to what the doctors will tell you you need to keep your body in tip-top shape, as well," said Dr Conor Wild, Owen Lab Research Associate and the study’s lead author.
"We also found that people that slept more than that amount were equally impaired as those who slept too little.”
Around half of all the participants typically slept for less than 6.3 hours a night, and as soon as they dipped under the seven hout threashold, brainpower started to decline.
And for those who slept under four hours a night, brain health was severely compromised.
Dr Wild told the Mail that brainpower declines as we get older and that "for those people sleeping four hours or less, it was as if we had aged them almost ten years...and it goes equally for those who sleep too much".
Over-sleeping can lead to something called "sleep inertia", which is when you feel groggy and sleep deprived.
Wake up in the middle of deep sleep, and that feeling will be even worse.
But if you're getting a decent amount of sleep (say, eight hours), you're getting almost no deep sleep by the end of it as the amount of deep sleep reduces over the course of the night - and that means that when you do wake up to the sound of your alarm, you'll feel well rested.
So that's another reason why you should never hit the snooze button.
MORE ON SLEEP
Saying that, the scientists did find some evidence that a single night's sleep can affect how well a person thinks.
Participants who slept more than usual the night before participating in the study performed better on the tests than those who slept their usual amount or less.
So although sleeping in for hours might do you no favours, having a really solid night's sleep before a big day might well help you to think clearer.
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