Study reveals why it's so hard to pay off a 'sleep debt'

·4 min read
A weekend lie-in won't make up for sleep deprivation. (Getty Images)
A weekend lie-in won't make up for sleep deprivation. (Getty Images)

You might assume you can make up for a bad night's sleep with a couple of early nights or a lie-in at the weekend, but new research has revealed it might not be quite so simple.

Many of us are struggling to get a good night's rest, with World Sleep Day statistics suggesting that 45% of the population suffers from sleep-related issues.

But sleep deprivation can have some pretty far-reaching impacts on our health, both physical and mental. 

While we like to believe that a couple of decent sleeps after a few bad ones might help us get back on track and "right" our body clocks, a new study shows that people who slept 30% less than they needed to for 10 days did not fully recover their cognitive function, even after seven nights of recovery sleep.

Read more: Have you got BNB (Busy Night Brain)? Here's how to reclaim sleep

Watch: Why is sleep so important?

So even a week of good sleep won’t cancel out a week of late nights and early starts.

The study, published in The Journal Plus One, assessed 13 people in their 20s who slept 30% less than they needed for 10 nights. 

Researchers found that the participants had not fully recovered most of their cognitive processing after seven nights of unrestricted sleep to recover.

It takes longer to recover from a sleep debt than you might think. (Getty Images)
It takes longer to recover from a sleep debt than you might think. (Getty Images)

While the study is small, sleep experts agree with the findings revealed in the research. 

“What the study showed is that there are things like memory and mental processing speed that will not be restored that quickly,” said sleep specialist Dr Raj Dasgupta, an assistant professor of clinical medicine at the Keck School of Medicine at the University of Southern California, who was not involved in the study.

“Definitely, the major parts of sleep loss can be recuperated, but there are things that you’re just not going to get back quickly. That’s why it’s so important not to have that sleep debt in the first place.”

Watch: The number one sign you got a bad night's sleep

This is something echoed in previous research, which found that people who were sleeping fewer than six hours a night for two weeks functioned as badly on cognitive and reflex tests as people who were deprived of any sleep for two full nights.

Read more: Should offices have ‘nap pods’?

A more recent study also found that catching up on sleep at the weekend is not enough to reduce the health risks of insufficient sleep during the week.

The study, by researchers at the University of Colorado Boulder, revealed we should place more importance on getting adequate sleep through the week, rather than simply during the weekend.

The findings were supported by another piece of research from the Public Assistance Hospital of Paris, which set out to uncover whether it is generally possible to catch up on sleep at the weekends

Of the 12,000 participants surveyed, more than a third got by on six hours or less a night midweek.

Nearly a quarter claimed to be getting at least an hour and a half less than they felt they ideally needed, racking up some serious sleep debt.

“Our survey shows about 75% of people with sleep debt did not find their way to get more sleep on the weekend or by napping,” said study author Dr Damien Leger.

“They probably did not take the time to do it or had poor conditions to sleep, [like a] noisy environment, stress or children at home.

Read more: How to sleep with a blocked nose

Recovering from the effects of a late night takes longer than you think. (Getty Images)
Recovering from the effects of a late night takes longer than you think. (Getty Images)

“So their sleep debt is not recovered.”

So how long will it take you to recover from a bad night's sleep?

“We do not know that exactly,” Dr Bhanu Prakash Kolla, a specialist at the Mayo Clinic's Center for Sleep Medicine, told CNN

“This study shows that maybe some tasks, especially in younger patients, can take longer to recover following sleep deprivation.”

The secret to recovering from a lack of shuteye, then, is to not get into sleep debt in the first place.

“We need to prioritise sleep and try and get at least seven hours each night,” Dr Kolla continues. “When we cannot, making sure that we have some time to recoup and being aware that the sleep deprivation impacts our mood and cognition is important.”

Thankfully there are some ways to ensure you don't fall into the sleep debt trap including keeping caffeine and alcohol intake to a minimum before bed, getting regular exercise and introducing a pre-bedtime wind down. 

You could also help prepare your mind for sleep by introducing a pre-bed tech ban as this sort of activity acts as a stimulant to the brain and makes sleeping more difficult.

Watch: How to improve your sleep

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