o preventing drowsy-driving?

A step closer to preventing drowsy-driving

Healthy Driving  |  By

There’s news just out of a small study that showed the potential of a blood test for drowsy-driving.

Using 36 healthy participants, researchers were able to identify with 92% accuracy, who had skipped a night of sleep and was therefore acutely sleep deprived. Unfortunately, chronic sleep deprivation was less easy to detect.

Why does this matter?

We are pretty clued up about the risks of drink-driving and very few of us, I hope, would put ourselves and others at risk by driving when drunk. But we haven’t yet woken up to the risk of drowsy-driving.

Driving when tired leads to a drop in driving performance from slower reaction times, reduced attention and reduced control of the vehicle.

Studies have shown that a person who drives after being awake for 19 hours (perhaps just driving home in the early hours of the morning after a sober night out) has driving skills similar to a driver who is over the legal limit.

A driver who has gone without sleep for 24 hours may as well be driving drunk.

But combine lack of sleep and alcohol (as you might after a long, boozy night) and you have a particularly deadly combination. Don’t just add the risks together, but multiply them.

What are the risks?

Your risk of a crash is 3 x greater after less than 5 hours of sleep, but 4 hours or less dramatically increases your risk to over 11 times that of a well-rested individual.

Falling asleep at the wheel is a pretty dramatic event and one that, hopefully, rarely happens but when we are tired, particularly chronically tired, we may have ‘microsleeps’. We are usually unaware of these two or three second lapses when our eyes close and our senses stop working… but it may be enough to send up headlong into on-coming traffic with drastic consequences. Not just for us but for others. Those well-publicised incidents when lorry-drivers fall asleep at the wheel demonstrate that it’s usually more than the sleepy driver who is injured – an average of 4.5 other people may suffer the consequences too.

The perils of sleepy driving are scientifically and soberingly dissected in detail in Matthew Walker’s excellent book “Why We Sleep”.

So, what about this blood test?

In the UK during 2016, fatigue was recorded as a contributory factor in 4% of fatal accidents and 2% of serious injury accidents. But this is likely to be under-reported as there is no way of knowing how tired a driver is at the time of the accident. In fact, a study specifically assessing driver fatigue found fatigue is more likely to account for 16% to 20% of all vehicle accidents in the UK.

The potential for testing for sleep deprivation in the same way that we use breathalysers or blood tests is still some considerable way off. But I applaud whole-heartedly that we are starting to take drowsy-driving seriously.

However, the issue of testing for sleep deprivation is a thorny one. I know I have had the odd ‘microsleep’ moment when I have ended up on the rumble strips after a sleepless night on duty in the hospital. Or when I have been kept awake for hours by a teething baby. And shift-workers face a daily disruption to normal sleep patterns. Should we be penalising people for drowsy-driving in the same way as people who knowingly drive after self-indulging in alcohol?

When you hear the stories of people who have lost loved ones or been seriously injured by a driver falling asleep at the wheel, the answer has to be ‘yes’. But at the same time, we need to seriously address sleep deprivation on a wider level.

More education on the perils of drowsy-driving is needed – think of the drink-driving awareness campaigns. And, also, much more work needs to be done on the issue of fatigue in the workplace – shift-working has an impact on all sorts of health issues such as obesity, type 2 diabetes, heart disease and more, probably part-related to chronically poor sleep. In fact, the British Medical Association has made tackling workplace fatigue from sleep deprivation one of it’s objectives for 2018. Doctors can be one of the professions most at risk due to irregular and anti-social hours as well as the high stress environment which makes sleep after a challenging shift less easy to come by.

Sleep is under-rated – often seen as a simple shut-down when the brain is actually busy recovering, reflecting and reviewing the events of the day. Sleep can be perceived as an indulgence, for lazy, low achievers as opposed to thrusting, successful leaders who often brag about needing 5 hours or less a night. The reality is that very few of us can function effectively on less than 7 or 8 hours.

It’s time to understand the true value of sleep, and facilitate and educate on ways to improve sleep. And to start taking drowsy-driving as seriously as drink-driving.


Emma E Laing, Carla S Möller-Levet, Derk-Jan Dijk, Simon N Archer. Identifying and validating blood mRNA biomarkers for acute and chronic insufficient sleep in humans: a machine learning approach. Sleep, 2018

Reported road casualties Great Britain, annual report: 2016 Personal injury accident statistics on public roads in Great Britain for 2016. 2017 Department for Transport

Horne JA, Reyner LA. Sleep related vehicle accidents. BMJ. 1995

Wake-up call. Tim Tonkin BMJ 2018

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