Driver tips: Sleep apnoea

Sleep apnoea is a killer condition causing you to fall asleep at the wheel and crash. Some research has found sleep apnoea sufferers are seven times more likely to crash. Yet you might not know you have it. Read this page to find out if there's a chance you do, and if there is, then go to your doctor to find out. Treatment is possible.

What is sleep apnoea?
Sleep apnoea is relaxation of muscles around the upper airway (in the throat behind the tongue and palate) causing snoring and obstruction to airflow during sleep. When this happens the brain responds by waking up and re-starting breathing. A few such interruptions in sleep may have little effect but frequent interruptions and waking cause tiredness upon waking, daytime sleepiness, lack of concentration, poor memory and, most dangerously of all, falling asleep while driving or operating dangerous machinery.

What causes it?
The shape of the throat and position of the lower jaw; the presence of swellings in the airway; fluid and fat in the tissue beside the airway, swollen tonsils and the ‘strength’ of muscle around the airway (it may be ‘weak’ in one in four people with diabetes) can all make sleep apnoea more likely.

Being overweight or obese can be a factor in some people. Having excess fat in the body as a whole resets the body’s metabolism making the muscle around the airway ‘weaker’, and is associated with more fat around the airway, compressing and narrowing it. The actual amount of fat beside the airway may be very small but can cause serious narrowing.

Even some people who are not seriously obese (BMI more than 30, see table) may have enough extra fat beside the airway to cause sleep apnoea.

How will I know that I might have it?
Sleep apnoea should be suspected if you have:
• Disturbed sleep
• Wake up coughing or fighting for breath during sleep
• Snore excessively
• Are tired on waking
• Fall asleep after meals (even without alcohol)
• Fall asleep in front of the TV
• Fall asleep during meetings
• Have a collar size of 17 or over (men only)
• Are obese (BMI more than 30, see table)
• You have fallen asleep or felt sleepy while driving in the past year or so
• Frequently have to use coffee or other caffeine containing bever ages to try to keep alert

How will I know if I am obese? 
This is a guide only, but you will probably have a BMI (Body Mass Index – weight in kg divided by height in metres squared) of 30 or over if your weight exceeds the value given for your height.

1.6m/ 5ft 3in = 76.8kg/ 12st 1lb
1.65m/ 5ft 5in = 81.7kg/ 12st 12lb
1.7m/ 5ft 7in = 86.7kg/ 13st 9lb
1.75m/ 5ft 9in = 91.8kg/ 14st 6lb
1.8m/ 5ft 11in = 97.2kg/ 15st 4lb
1.85m/ 6ft 1in = 102.7kg/ 16st 2lb
1.9m/ 6ft 3in = 108.3kg/ 17st 1lb

Do not drive with uncontrolled sleep apnoea
If you are suffering from sleepiness at the wheel, have well-founded suspicion that you have sleep apnoea, or have been diagnosed with sleep apnoea and the symptoms are not yet controlled (see below), or cannot be controlled, it is not safe to drive. Do not drive.

What do do if you suspect you have sleep apnoea
If you suspect that you may have sleep apnoea or believe that your body weight may be putting your driving career at risk speak to your fleet manager and talk to your GP. Ask for a referral to a sleep clinic or a department of respiratory medicine for a sleep study and emphasise that your driving career may depend on a rapid referral and prompt treatment. If you are overweight or obese there are some options for losing weight available through your GP practice – ask for a prompt referral.

The latest research from Sweden shows that a majority of men with moderate and severe sleep apnoea can lose enough weight to improve their sleep apnoea symptoms in just 9 weeks [1] – a formula diet programme of this kind is available in the UK, although not yet through the NHS. If a diagnosis of sleep apnoea is made it is readily treated with the use of a face mask and air-pump which raises the air pressure going into your airway helping to keep it open. This form of treatment, known as CPAP (Continuous positive airway pressure) has been proved scientifically to greatly improve the symptoms and the bad effects of sleep apnoea in most users.

[1] Johansson K, Neovius M, Lagerros YT, Harlid R, Rossner S, Granath F, Hemmingsson E. Effect of a very low-energy diet on moderate and severe obstructive sleep apnoea in obese men: a randomised controlled trial. BMJ 2009; 339: b4609 doi 10.1136/bmj.b4609 .

Tags: fatigue tiredness advice sleep apnoea