Shift work sleep disorder: symptoms, risks and what helps

Everyone has an internal body clock in the brain that produces circadian rhythms, signalling when it is time to sleep and when to wake. The Sleep Charity explains that this is often set by exposure to sunlight, and that shift workers must fight the body's natural rhythms to stay awake when the body expects to sleep and then try to sleep when it expects to be alert.

Shift work sleep disorder is the name given when this mismatch becomes an ongoing problem. The Sleep Charity says it starts to interfere with family life and work. Many shift workers feel they have not had enough sleep and, even when they sleep well, find themselves lethargic, irritable and unable to concentrate.

The NHS lists shift work, along with stress, noise, alcohol, caffeine and jet lag, among the most common causes of insomnia. Insomnia that lasts less than 3 months is called short-term insomnia, and insomnia that lasts 3 months or longer is called long-term insomnia, according to the NHS. Not everyone who works shifts develops a disorder, but sleep that is repeatedly short or broken warrants attention.

The symptoms overlap with those of insomnia and of general sleep deprivation. The Sleep Charity lists them as below, and notes that daytime sleep is less efficient than night-time sleep because you are constantly battling disturbance such as light and noise while challenging your circadian clock. HSE adds that night workers' day sleep is often lighter, shorter and more easily disturbed.

• Trouble falling asleep or staying asleep when you have the opportunity to sleep.

• Excessive sleepiness, especially during shifts or on the journey home.

• Microsleeps, which last just a few seconds.

• Lack of energy, irritability and low mood or depression.

• Trouble concentrating, with slower reactions and memory lapses.

HSE describes fatigue as a decline in mental or physical performance that results from prolonged exertion, sleep loss or disruption of the internal clock. It says fatigue results in slower reactions, reduced ability to process information, memory lapses, decreased awareness, lack of attention and underestimation of risk, and that it has been implicated in 20% of accidents on major roads.

The Sleep Charity says there is a 25 to 30% higher risk of injury working night shifts than day shifts, and the same is true of 12-hour shifts compared with 8-hour shifts. It also reports that drivers who work shifts are a high-risk group for fatigue-related crashes, especially at the end of a night shift or a long shift, and suggests using public transport or a taxi after a night shift where possible.

The Sleep Charity also reports claims that anti-social hours can prematurely age the brain and that night shift work is linked to obesity. These are reported links rather than proven effects on any one person. HSE's guidance is that fatigue needs to be managed like any other hazard.

The Sleep Charity advises making the sleeping environment cool, quiet and dark, with blackout curtains or blinds, an eye mask and earplugs, and agreeing with housemates how to keep noise down. It suggests avoiding caffeine for about five to six hours before sleep, choosing a lighter meal rather than a large heavy one, and winding down with relaxation rather than devices. Wearing sunglasses on the way home may help because daylight encourages the brain to feel awake, though it advises caution if you are driving.

For napping the Sleep Charity says a nap of around 90 minutes at home before a night shift can help boost energy when moving from days to nights, and after a final night shift a short morning nap of one to two hours, then keeping to as normal a day as possible. It says you are likely to need two normal nights to re-establish a usual sleep pattern. Napping at work should only be used in organisations with a high risk of involuntary sleeping and with proper facilities.

The NHS general sleep advice also applies: keep a regular sleep routine, make the bedroom quiet, dark and cool, avoid large meals, alcohol and nicotine in the 1 to 2 hours before bed, and if you are awake after about 20 minutes get up and do something relaxing before going back. Because your sleep times vary, the Sleep Charity suggests taking bedtime cues from the environment rather than from the clock.

The NHS advises seeing a GP if changing your sleeping habits has not helped, if you have had trouble sleeping for months, or if sleep problems are affecting your daily life in a way that makes it hard to cope. A GP will try to find out what is causing the problem so you get the right treatment, and may offer cognitive behavioural therapy (CBT) either face to face or through an online programme. You may be referred to a sleep clinic if you have symptoms of another sleep disorder such as sleep apnoea.

The NHS says GPs now rarely prescribe sleeping pills for insomnia because of serious side effects and the risk of dependence, and that they are only prescribed for a few days or weeks at most if insomnia is very bad and other treatments have not worked. A pharmacist can recommend sleep aids that may help for 1 to 2 weeks, and the NHS says they should not be taken for longer. Do not drive when you feel sleepy.

The NHS lists other conditions that can cause insomnia, including sleep apnoea, restless legs syndrome, an overactive thyroid, menopause and mental health conditions, so a GP review is worthwhile if poor sleep does not settle once your shifts are accounted for.

HSE says there is no single optimal shift system that suits everyone, but that a planned and systematic approach to assessing and managing risks can improve safety. It names workload, work activity, shift timing and duration, direction of rotation and the number and length of breaks as key risk factors in shift design, and says the legal duty is on employers to manage fatigue risks. Compliance with the Working Time Regulations alone is not sufficient.

If shift work is affecting your health, it is reasonable to raise it with your manager, occupational health service or trade union representative, and to ask whether the pattern, breaks or rotation can be changed. HSE advises that employees should be consulted on working hours and shift patterns, although it points out that preferred patterns are not always the healthiest.

On the NHS, sleep problems are assessed by a GP, who can offer advice, CBT-based support and, where a different sleep disorder is suspected, referral to a sleep clinic. If your employer has an occupational health service, it is a sensible place to ask about adjustments to your shift pattern.

Private sleep clinics and psychologists offer faster access to assessment, sleep studies and CBT for insomnia. If you go private, the same basics apply. The NHS notes that sleeping pills are rarely prescribed because of side effects and dependence, so ask what a clinic would offer beyond sleep habits and CBT.