Sleep apnoea

Key facts

  • People who suffer from sleep apnoea are 2.5 times more likely to be involved in a road crash [1];
  • Around 1.5 million adults in the UK are thought to suffer from sleep apnoea [2]
  • Anyone who suffers excessive sleepiness as a result of sleep apnoea must notify the DVLA about their condition and stop driving.


Obstructive Sleep Apnoea (OSA) is a condition that causes sufferers to briefly stop breathing while they are asleep. This interrupts sleep and causes excessive daytime sleepiness. People with OSA are prone to nodding off during the day, and if they are driving, this could lead to a crash.

Research has shown that people with OSA are about 2.5 times more likely to be involved in a road crash than people without the condition [3]. In 2018, 62 people were killed in crashes involving a driver who was impaired by fatigue, and 339 were seriously injured [4].

Many people who suffer from OSA do not realise it, due to lack of awareness about symptoms. It is estimated that 1.5 million adults in the UK are living with OSA, but just 330,000 are currently diagnosed and treated [5]. Further research has found up to 80% of OSA cases may not be diagnosed – meaning many drivers could be putting themselves in danger by getting behind the wheel [6].

How does OSA affect sleep?

OSA is one of the most common medical causes of excessive daytime sleepiness [7]. People with OSA suffer interruptions in their breathing while they are sleeping. The interruptions can last 10 seconds or longer and occur when the muscles around the throat relax too much during sleep. The brain briefly wakes a person up to re-start their breathing, interrupting sleep. Usually the person does not remember waking up so is unaware they have the condition. Because of the repeated waking, sufferers have poor-quality sleep so will feel sleepy during the day and be prone to nodding off [8].

Some people with OSA may only wake a few times in the night, and suffer minimal daytime sleepiness. The more severe form of the condition, where sufferers may wake hundreds of times in the night and suffer severe daytime sleepiness, is known as Obstructive Sleep Apnoea Syndrome (OSAS). Approximately 5% of people are thought to suffer from OSAS [9].

Fatigue severely impairs your ability to drive safely. For this reason, drivers suffering from untreated sleep apnoea are considered highly dangerous. Some experts believe untreated sleep disorders are as dangerous on the roads as drink-drivers [10].

Learn more: Read our fact page on the wider risks of driver tiredness.

Who is most likely to have OSA?

The highest-risk group for OSA are middle-aged men who are overweight, with a collar size of 17 inches or more [11]. However, not all sufferers fit this profile.

Anything that makes the throat narrower (such as enlarged tonsils or set-back lower jaw) means it is easier for the throat to close off and block the airway. Contributory factors can include smoking and drinking (especially before going to sleep) and taking sleeping pills or other sedative medications [12].

Professional drivers such as truck drivers are known to be at higher risk for sleep apnoea. Studies have shown that commercial drivers have a higher prevalence of OSA than the general population (between 28% and 78%) [2a]. Another study of truck drivers in Italy found up to half may suffer at least one sleep-related breathing condition, compared with 6%-17% of other people [13].

What are the symptoms of OSA?

The main symptoms of OSA are snoring and daytime sleepiness. Even slight sleepiness will affect monotonous tasks such as reading, watching TV and driving on trunk roads. If a sufferer’s sleepiness gets worse, it can lead to them falling asleep while talking or eating [14].

Snoring does not necessarily mean a person has OSA, but frequent, very loud snoring together with daytime sleepiness is likely to indicate OSA.

Other symptoms that may indicate OSA include [15]:

  • choking episodes during sleep
  • morning headaches
  • depression
  • waking feeling unrefreshed
  • difficulty concentrating
  • irritability.

The Epworth Sleepiness Scale is a self-assessment test that can be used to determine whether someone is likely to be suffering from OSA. People who score moderate or high risk on this questionnaire should seek medical advice immediately, and may need to notify the Driver and Vehicle Licensing Agency (see below).

What is the law on OSA?

If a tired driver causes a death, they can be charged with death by dangerous driving if evidence proves they were impaired through fatigue. The maximum penalty is 14 years in prison.

In 2018, the government introduced new guidelines for drivers who suffer from OSA [16]. Under the guidelines, drivers who have been diagnosed with OSA but do not experience excessive sleepiness that is likely to affect their ability to control a vehicle do not have to report their condition to the DVLA. Drivers who suffer excessive sleepiness and suspect they may have OSA should stop driving, but do not have to notify the DVLA until a diagnosis has been confirmed.

Once a driver is confirmed to have OSA and suffers excessive sleepiness, they must stop driving and immediately notify the DVLA.

The changes followed a new EU Directive introduced in 2016, which changed the requirements for reporting OSA in Britain.

How is OSA treated?

OSA is treatable, so anyone who thinks they may be suffering should seek medical advice as soon as possible so they can start getting uninterrupted sleep again. Anyone who drives and thinks they may be suffering should stop driving while they seek diagnosis and treatment, to ensure they are not putting themselves and others at great risk.

Early diagnosis and treatment is also important because, apart from the immediate danger of causing a crash by nodding off at the wheel, untreated OSA increases the risk of high blood pressure, stroke and heart attacks, and can reduce life expectancy by 20 years [17].

Referral to a sleep unit will almost always be necessary for suspected sufferers of sleep apnoea so that they can be diagnosed and offered treatment. Some simple approaches are also worth trying to reduce the causes of mild sleep apnoea:

  • losing weight
  • stopping smoking
  • sleeping on your side
  • keeping the nose clear, for example by using a nasal spray, or raising the head end of the mattress
  • reducing or stopping evening alcohol consumption [18].

A person diagnosed with OSA will usually be treated with a continuous positive airway pressure (CPAP) machine, which keeps the throat open with the use of pressurised air. The person must wear a mask, connected to a small pump beside the bed, over their nose during sleep. CPAP machines greatly improve the person’s sleep: sufferers usually notice an immediate, vast improvement in their quality of sleep [19]. Research has found that, for people with OSA, even a few hours’ sleep with a CPAP machine reduces sleepiness at the wheel more than a full night’s sleep without CPAP [20].

For mild cases of OSA, a mandibular advancement device (MAD) may be more appropriate than a CPAP machine. This is a device like a gum shield, to be worn over your teeth when you are asleep. It is designed to hold your jaw and tongue forward to increase the space at the back of your throat. If you think a MAD may help you, it is recommended that you ask a dentist who is experienced in treating OSA fit one. Buying a ready-made MAD online or from a specialist store is not recommended, as poorly-fitted MADs can make the symptoms worse [21].

In some rare cases, surgery may be an option. However, surgery is not often as successful at treating the symptoms as CPAP, and runs the risk of complications, so is usually only considered if all other treatment options have failed and the condition is seriously affecting a patient’s quality of life [22].

Take action: Support Brake’s Driving for Zero campaign to raise awareness of the risks of impaired driving, including sleep apnoea.

How can employers support drivers with OSA?

Under the Health and Safety at Work Act, UK companies and organisations have a responsibility for their employees while they are driving for work purposes. This means that they may be liable for road crashes caused by or involving employees who are suffering from excessive sleepiness.

Brake recommends that companies with staff who drive for work train their drivers and managers to look out for common symptoms. Suspected sufferers should be taken off driving duty immediately and referred for medical assessment. Annual health checks can also help to identify potential OSA sufferers. Research has indicated that medical examinations for drivers that look for common health issues among sedentary workers, such as obesity, hypertension and diabetes, can help identify OSA in drivers who may not have noticed the symptoms themselves [23].

Claire Michell, from the Sleep Apnoea Trust, advises employers to be sympathetic to drivers who may have OSA. Drivers often won’t want to admit there is a problem because they will be scared they will lose their job. Employers can help with this by educating line managers about the condition, particularly the crucial fact that it is treatable.

Learn more: Employers can access guidance from Brake on OSA and a broad range of other road safety topics to help them prevent at-work crashes at

Sources of further information:

End notes

[1] American Academy of Sleep Medicine (2015), Risk of motor vehicle accidents is higher in people with sleep apnea
[2] Rejon-Parrilla, J. C. et al (2014), Obstructive sleep apnoea health economics report
[3] American Academy of Sleep Medicine (2015), Risk of motor vehicle accidents is higher in people with sleep apnea
[4] Department for Transport (2019), Reported road casualties in Great Britain, annual report: 2018, table RAS50001
[5] Rejon-Parrilla, J. C. et al (2014), Obstructive sleep apnoea health economics report
[6] Bonsignore, M. (2017), Sleep apnea and its role in transportation safety
[7] Chervin, R. D. (2019), Approach to the patient with excessive daytime sleepiness
[8] Sleep Apnoea Trust Association, Frequently asked questions
[9] OSA Partnership Group (2015), Four-week wait campaign: For the treatment of obstructive sleep apnoea syndrome (OSAS)
[10] NHS University Hospital Southampton (2019), Doctor warns untreated sleep disorder ‘as dangerous as drink driving’
[11] Sleep Apnoea Trust Association, Frequently asked questions
[12] NHS (2019), Sleep apnoea
[13] EMJ (2019), Review of the 29th European Respiratory Society (ERS) International Congress
[14] Sleep Apnoea Trust Association, Frequently asked questions
[15] NHS (2019), Sleep apnoea
[16] DVLA (2018), Assessing fitness to drive: a guide for medical professionals
[17] Rejon-Parrilla, J. C. et al (2014), Obstructive sleep apnoea health economics report
[18] NHS (2019), Sleep apnoea
[19] Sleep Apnoea Trust Association, Treatment of sleep apnoea
[20] Queensland University of Technology (2014), One night CPAP withdrawal impairs performance at a driving simulator task
[21] British Lung Foundation, Treatment for obstructive sleep apnoea
[22] Ibid.
[23] Meharry Medical College (2011), Factors associated with obstructive sleep apnea among commercial motor vehicle drivers

Page last updated: April 2020

Tags: fatigue tiredness sleep apnoea