In the second of a short series of articles on the importance of sleep Dr Guy Meadows tells us about some of the science of sleep
Research says that lack of sleep can have the same cognitive and motor impairment consequences as being over the drink drive limit. Photo source: fotolia
It’s 8am and you’re washing down your breakfast with a glass of wine before setting off for work.You decide to drive to the station, dropping off your kids at school on the way. Arriving at your desk you realise it’s time for another glass to help start the day.
While I’m sure that such a scene is far from most of our perceptions of what constitutes a healthy start to the day. If you’re sleep deprived, you might as well have been drinking. Research suggests that staying awake for 17 to 18 hours has the same cognitive and motor impairment as having a blood alcohol level of 0.05 per cent, the legal limit. At 20 hours of wakefulness your performance is the equivalent of being twice over the legal limit.1
The UK is currently going through a sleepless epidemic, which is therefore very concerning. A national survey of UK working adults reported that 46 per cent regularly achieved only five-six hours sleep per night, well below the recommended seven-eight hours.2 Modern working habits don’t help, with many of us restricting our sleep during the week and then attempting to catch up on the weekend, something that gradually accrues a sleep debt.
The relative normality of this kind of moderate sleep restriction has recently attracted the attention of sleep scientists. The negative impact of total sleep deprivation is well established…think torture! But the affects of continually missing out on a few hours sleep every night are less well understood.
One pioneering study found that sleeping six hours per night for 14 nights, compared to regularly getting eight hours per night, resulted in the equivalent reduction in mental and emotional performance as two full nights without sleep. If this wasn’t bad enough, the more sleep deprived the individuals became, the less sleepy they reportedly felt, despite displaying worsening cognitive impairments. In short, when sleep deprived we’re unable to recognise the fact that we’re sleep deprived, much akin to drinking alcohol.3
Such vulnerability to sleep deprivation stems from the part of the brain known as the pre frontal cortex. Responsible for many of the higher order executive functions that we rely on so heavily to function during the day, it’s also incredibly sensitive to lack of sleep. If you didn’t sleep well last night, it’s possible that you’re struggling to stay focused on this article, although you may not be aware of it!
Your capacity for focused attention could be described as the most important cognitive function, it allows you to stay focused on what you’re doing long enough to successfully complete tasks. Without such an ability we wouldn’t be able to learn, communicate, problem solve, memorise or perform many other higher order skills. Research shows that if you regularly experience poor sleep you are three times as likely to lack concentration during the working day and struggle to ‘get things done’.4
The vulnerability of our pre-frontal cortex to lack of sleep also explains why we feel more stressed after a night of poor sleep. Neuroimaging studies reveal that a sleep deprived brain spends more time in the amygdala, the primitive threat detecting part of our brain. The net result is that we tend to view ourselves, others and the world around us in a more negative light, something which results in us over reacting to emotional events and experiencing more negative emotions.5
More concerning is that poor sleep increases the likelihood of us making riskier decisions because sleep deprivation deactivates the area of the brain responsible for assessing risk and stimulates the area connected with positive outcomes.6 This could explain why sleep deprivation has been found to be at the heart of most major disasters including Chernobyl, Exon Valdez and the Challenger space shuttle.
In addition to mental performance, the negative consequences of poor sleep can also be seen in our ability to maintain optimum physical health. Recently researchers discovered that getting less than six hours per night for two weeks, when compared to sleeping seven hours, quadrupled the risk of catching the common cold.7
Sleep protects us during the day by boosting our immune system at night. Add this to the fact that getting a good night’s sleep has been proven to be essential for washing our brains of toxins built up during the day, helping us to manage an ideal weight and keeping our heart and blood pressure healthy; sleep truly is the most powerful natural performance enhancer known to human kind.
Investing in sleep programmes that educate employers on the benefits of sleep and employees on how to achieve regular good quality sleep could therefore be considered as the most valuable staff training ever.
Tomorrow, how not to let stress and anxiety affect your sleep