Irregular sleeping patterns can have a detrimental effect on a person’s health. Occupational health specialists can help to address these problems, says consultant occupational physician Dr Colin Payton.
Sleep disorders have serious adverse consequences for both fitness for work and health in general. Poor sleep or insomnia leading to health-related poor performance at work is something that occupational health practitioners should be aware of, and any assessment of workers with fatigue or daytime sleepiness should include enquiry into their sleep patterns.
By far the most common sleep disorder is insomnia and the most common underlying cause is depression. For those suffering from this, sleep is often broken and, typically, there is early morning wakening, where the patient wakes in the early hours of the morning and is unable to get back to sleep. They do not feel refreshed by sleep and are chronically fatigued.
Also seen in depression, but much less commonly, is hypersomnia – excessive sleeping. Both insomnia and hypersomnia should respond to treatment of the underlying depression. Getting back to work also helps to re-establish the normal circadian rhythm and assists restoration of a normal sleep pattern. Anxiety disorders, including generalised anxiety disorder (GAD) and panic disorder, also often disturb sleep due to arousal and rumination during the night.
Physical sleep disorders
The most common physical sleep disorder is obstructive sleep apnoea-hypopnoea syndrome (OSA), generally known as sleep apnoea. It is caused by parapharyngeal fat deposits that make the pharynx narrow and floppy, leading to it collapsing during sleep. There are essentially two elements to the syndrome that affect sleep. The first is apnoea, which is a complete cessation of breathing lasting for at least 10 seconds. The second is hypopnoea, which is a reduction in tidal flow, ie less effective breathing. Apnoea in particular leads to arousal during sleep related to the increased respiratory effort. In mild sleep apnoea there are five to 15 arousals per hour; in severe cases there are more than 30.
Sufferers are usually, but not always, obese and often have a large collar size (more than 17 inches in men and more than 16 inches in women). It is two to three times more common in men, as men have a more central body fat distribution. For the same reason, it is more common in post-menopausal women.
Patients with sleep apnoea complain of:
- snoring (reported by their sleep partner, and often in a characteristic crescendo pattern leading up to a period of apnoea followed by restoration of breathing);
- excessive daytime sleepiness, particularly after meals and more so in the afternoon or during a night shift. Less commonly, workers actually fall asleep at work. This usually happens at times of prolonged low stimulation, such as working alone at their desks, working on a computer or watching CCTV monitors. The Epworth Sleepiness Scale, a simple 10-point questionnaire, is an effective objective measure of daytime sleepiness. Associated symptoms include chronic fatigue, irritability, headaches and problems with memory and concentration; and
- restless sleep (abnormal movements, agitation, reported by their sleep partner).
Investigation is by respiratory laboratory sleep study (or polysomnography), which measures the number and frequency of dips in oxygen saturation during sleep. Continuous positive airway pressure (CPAP) is the standard treatment and can be very effective, although not all patients can sleep wearing the tight-fitting mask all night. Other measures to improve sleep should also be considered, in particular losing weight. Sleep apnoea in obese patients is a selection criterion for bariatric surgery such as gastric banding.
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People with mild sleep apnoea may be able to continue at work. Those with severe symptoms are less likely to be fit for work until they get effective treatment, especially if they work in responsible, safety-critical or healthcare roles. There is also a significant increase in the risk of road traffic accidents and the DVLA advises that both Group 1 and 2 driving should cease until there is satisfactory control of symptoms. The DVLA provides a helpful driver leaflet on this.
Narcolepsy
Narcolepsy is a less common disorder, affecting between two and six people per 10,000 in the UK, and presents particular problems for those who work. It comprises periods of extreme drowsiness often followed by a short period of sleep, occurring about three or four times a day. These periods are often after eating. Other symptoms include hallucinations associated with the naps and cataplexy, sudden muscular weakness that can cause the head to fall forward or even complete collapse. Treatment with modafinil can be effective in reducing daytime sleepiness.
People with narcolepsy are able to work, especially if their symptoms are well controlled. They should be advised to tell managers and colleagues about their condition. If they work part time or flexibly, a planned afternoon nap can be helpful; they should also have good sleep hygiene and try to avoid obesity. Narcoleptics cannot hold a Group 2 driving licence but a time-limited Group 1 licence is permitted when symptoms are controlled.
Parasomnias
Parasomnias are odd behaviours or atypical movements during sleep that occur in about 50% of people at some point in their lives. They include sleepwalking, nocturnal epilepsy, restless legs syndrome and periodic limb movement disorder. They can be precipitated by sleep deprivation, stress, physical illness and drugs such as benzodiazepines. All of these conditions can disturb sleep and lead to daytime sleepiness and chronic fatigue.
Circadian rhythm disorders
Like animals and plants, humans have a circadian rhythm, an intrinsic 24-hour cycle that controls aspects of our behaviour, physiology and biochemistry. The cycle is synchronised with external factors, principally daylight. It is controlled by neuroendocrine processes via the hypothalamus and the pineal gland, which produces melatonin, a hormone, in high levels during the night and much lower levels during daylight.
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Circadian rhythm sleep disorders are conditions affecting sleep wherein the circadian rhythm is disrupted. In jet lag and shift work, sleep disorder disruption is caused by external factors. There are a number of other symptoms, which are due to an internal misalignment between the body’s circadian rhythm and the environment.
Keeping a healthy body clock
Workers who travel internationally should be advised to partially adapt to the new time zone before they travel – go to bed an hour earlier if travelling east, an hour later if travelling west – and adapt to local time as soon as they arrive. Exposure to daylight helps to reset the body clock to the new time zone. They should be allowed time to adjust and not be expected to take part in important or challenging work as soon as they arrive at their destination. Some studies suggest that melatonin (available only on prescription in the UK) can help to induce sleep if taken shortly before bedtime.
Workers with shift-work sleep disorder find it difficult to adjust to different sleep-wake cycles and as a result suffer with insomnia and/or excessive sleepiness. It can help if they are allowed to have a consistent shift pattern rather than alternating rapidly between day shifts and night shifts.
There is a common misconception that people can catch up on sleep. Some working people with active social lives get very little sleep during the week and then try to catch up at the weekend. This simply disrupts their circadian rhythm, as they are going to sleep very late at night and then sleeping until late afternoon at the weekends. This can have much the same effect as jet lag and when Monday morning comes they feel as though they are getting up in the middle of the night. This can contribute appreciably to poor attendance and performance, especially at the start of the week.
Dr Colin Payton is a full-time NHS consultant occupational physician at the Royal United Hospital in Bath.
References
Christie J. “1, 2, 3, If employees suffer from insomnia, how can an employer manage the knock-on effects?” Occupational Health, vol.63, no.2, February 2011.
Epworth Sleepiness Scale
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DVLA. “Tiredness can kill – advice for drivers”.
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