Fatigue – wake-up call for drivers
- The body clock
- The symptons
- Deadly combinations
- What causes fatigue
- The onset of fatigue
- Affected by fatigue
- Ian’s story
- Wake up to the dangers
- Other tips for staying alert
- Fatigue video
There’s a lot more to the topic of driver fatigue than simply nodding off at the wheel. Falling asleep is of course a form of fatigue, but it’s the most extreme form, occurring only after a number of other – easily recognisable – symptoms have been ignored. Your driving can be affected by fatigue long before you are so tired that you are in serious danger of falling asleep at the wheel.
The body clock
We have an in-built body clock in the brain, coordinating daily cycles which are known as circadian rhythms. Our clock programmes us to feel very sleepy between 3 am and 5 am, and to experience another dip in alertness between 2 pm and 4 pm. It’s at these times that we experience our worst physical and mental performance of the day. No surprise, then, to know that there’s an increase in fatigue-related crashes at these times.
It will take you longer to get to grips with information which you would interpret immediately when fully alert. For example, you could find yourself spending some while simply staring at a road sign – or worse – a hazard ahead, without being able to interpret the message it’s offering and therefore being able to react promptly.
You may also find – especially on a long, dull motorway journey – that you may be drifting out of your lane, and finding it quite difficult to stay within the markings of the lane you’re using. You may think you’re going at a constant speed, but it’s a common trait among fatigued drivers to change speed more frequently and for no good reason. You may also find yourself fidgeting in your seat in an attempt to wake up a bit.
The result? Fatigue is reckoned to be the cause of a large number of single vehicle crashes involving a car striking a tree or other rigid object, and severe head-on collisions. Researchers believe fatigue is involved in between 10% and 25% of all crashes and it accounts for around 20% of all serious accidents on motorways.
Driver fatigue becomes even more of a risk when it combines with other factors, such as speeding and alcohol impairment. Drink-driving is particularly dangerous in combination with fatigue, because alcohol can affect a driver’s alertness long before he or she reaches the legal drink-drive limit. Any amount of alcohol can combine with fatigue to affect your driving.
Driving at higher speeds when affected by fatigue also increases risk, as a fatigued driver with slower reactions will need more time to react to events unfolding ahead of him. However, higher speeds mean you have LESS time to react.
What causes fatigue?
One of the most commonly known causes of fatigue is, unremarkably, lack of sleep. We all have our own sleep needs, some more than others. An average daily sleep requirement is between seven and eight hours. If you miss your full night’s sleep, for whatever reason, you’ll feel tired the next day. Researchers have found that as little as two hours sleep loss on one occasion can affect your reaction time, mental functioning, memory, mood and alertness.
Allow your sleep loss to go unchecked across several nights and you build a significant sleep debt. If you let this become too large, then your brain will eventually go to sleep involuntarily (micro-sleep), regardless of where you are and what you are doing.
Micro-sleeps generally only last a few seconds, but can obviously be very dangerous if they occur while you’re driving. For example, during a two-second micro-sleep at a speed of 60 mph, a car will have travelled around 56 metres without you in control.
The onset of fatigue
Professor Jim Horne from Loughborough University explains clearly: “Sleep doesn’t come spontaneously from nowhere. You can’t be driving along alert one minute and falling asleep the next. There’s always adequate time to realise how sleepy you are.”
People who are most likely to be affected by fatigue
Although we are all likely to experience some level of fatigue, it is more prevalent among the following groups:
Young people, with lifestyles that involve ‘burning the candle at both ends’, going to parties, staying up late, taking risks and being on the road at night.
Shift workers, whose disrupted sleep patterns can easily lead to fatigue. Night shift workers have the greatest risk of sleep disruption.
People suffering from sleep disorders can of course have the quality and quantity of their sleep affected. The most common disorder is sleep apnoea, which affects approximately five percent of the middle-aged population. In sleep apnoea, the sleeper’s throat relaxes so deeply that he or she actually stops breathing. The sleeper gasps, wakes up enough to start breathing normally, and then goes back to sleep without being aware of any problem. This occurs as often as 600 times a night, leaving the apnoea sufferer thinking he has had a full night’s sleep, yet inexplicably tired throughout the day.
The most common risk factors for sleep apnoea, which is usually accompanied by snoring, are being overweight, male and middle-aged.
Ian Bradshaw is a TV news cameraman and co-owner of a successful production company. The birth of his daughter Jessica in 2006 was, naturally, a very happy occasion. Little was Ian to know that within three months his doctor would order his driving licence to be taken away because of the extreme fatigue he was suffering.
“Jessica seemed to sleep for no more than 15 minutes at any time,” says Ian. “Day or night, this appeared to be as long as she could last without waking up and screaming the place down. My wife and I soldiered on as you do. After all, everyone who has been a new parent will be familiar with that spaced out feeling that goes with extreme fatigue. So at first we didn’t reckon we were any different from everyone else.
“However, for me things went beyond the stage of being able to cope with – basically – no sleep night after night. I started dropping off involuntarily at the office for a few seconds during the middle of a meeting or while at my desk. I went to see my GP on another matter, but the fatuge issue came up and he immediately told me there was no way he could let me be out and about in a car while I was in this state.”
“Thankfully, Jessica’s screaming and wakefulness didn’t last much longer and we adapted to a routine that allowed me and my wife to cope with whatever disruption she did cause. Consequently I was able to get my licence back and return to work, but I am extremely watchful these days of any creeping signs of fatigue – not just in me but in my wife and the team at work, too.”
Wake up to the dangers:
Make sure you get plenty of sleep before a long journey. Plan to drive during times of the day when you’re normally awake, don’t push yourself to complete a long journey all in one go. Schedule a night stop somewhere rather than ‘pressing on’ regardless.
Avoid driving during times when you know you’ll be at your most drowsy. It makes sense to take a break after lunch and to be asleep between midnight and 6 am.
If you’re on a long journey, the Highway Code advises a 15-minute break every two hours as a minimum. Take more frequent breaks if you need to. Make sure they’re proper breaks, too. Get out of the car, have some fresh air, stretch or exercise a little. If you’re tired, then take a nap if it’s safe.
Don’t delay taking a nap. A short sleep of 15 to 30 minutes can be helpful, but if you sleep more than 40 minutes you will find it hard to wake up and be alert – at least for 15 minutes after waking.
Avoid heavy meals on journeys, especially at lunchtime, as these can exacerbate sleepiness in the afternoon.
Drinks with a caffeine content can help you stay alert, but remember, their effects are not instant. Research shows that taking a caffeinated drink, followed by a 20-minute nap, appears to be the best short term measure for combating fatigue.
Other tips for staying alert:
Wind the windows down from time to time, to get some fresh air into the vehicle.
If possible, share the driving.
Make sure you’re not taking any medications that could make you drowsy. Travel sickness tablets and some cold remedies are examples of drugs that can cause drowsiness.
The advice offered here for dealing with fatigue constitutes little more than emergency measures to ensure you can reach a rest stop in safety. And remember, the symptoms will simply return if you don’t have the opportunity for proper, quality rest. There is no substitute for being well rested before a journey.
Our additional information sources
RoSPA (www.rospa.com), Loughborough University Sleep Research Centre (www.lboro.ac.uk), Land Transport New Zealand (www.ltsa.gov.nz).