Shift work can have a significant impact on sleep and health. These occur via a number of different mechanisms but the three main sleep-related problems with shift work are:
Strategies to minimise the impact of shift work generally involve targeting each of these three areas as well as trying to best manage the shift hours and rotations, particularly if you are able to have some input into how rostering or shifts are designed.
Unfortunately, for many shift workers, rosters or shift design are managed by the workplace so there is little opportunity to manage shift design. However, if you can have some input in to shift or roster design, consider shift timing, length and the amount of time between shifts.
Shift timing: As a general principle shifts that are the easiest to deal with are ones that rotate slowly and gradually later. For example, shifts that involve a morning shift for a few weeks, then rotate to an evening shift for a few weeks before rotating onto night shift for a few weeks are generally the easiest to adjust to. This is because there is a gradual rotation that the body clock can acclimatise to and maintaining each shift for a couple of weeks allows the body clock to become adapted to that time. Shifts that are much harder to deal with are those that rapidly change such as shifts where there may be two long day shifts, a day off then two long night shifts then a couple of days off. The body cannot adapt rapidly enough to deal with this type of rotation, which leads to difficulty sleeping both between shifts and on days off and results in sleep deprivation.
Shift length: Another factor that is important in shift design is the length of shifts. Long shifts, such as 12-hour shifts do not leave much time in the day for winding down, or other activities such as exercise or leisure or commuting. For example, someone who works a 12-hour shift but has a 45-minute commute to and from work only has 10 hours in the day for everything apart from work and commuting. By the time they factor in meal preparation and some personal tasks or family tasks around the home, often sleep is the thing that suffers. This can lead to the development of insomnia as people feel pressured to try to get to sleep as quickly as possible which in turn makes it more difficult for them to sleep.
Whilst long shifts, such as 12 hour shifts, can help to reduce the number of working days per work, and make rostering easier as there are only 2 shifts per 24 hours, rather than 3, they are hard to sustain, and after 3 x 12 hour shifts people begin to get tired and performance on the job can become impaired. It’s better for rosters to be designed to have 3 x 8 hour shifts per 24 hours so there is adequate time for managing health and sleep.
Amount of time between shifts: Quick turnaround between shifts doesn’t allow adequate time for winding down and sleep before the next shift starts. An example of a quick turnaround is finishing an afternoon shift at 10pm, then having an early shift the next day starting at 7am. That only allows 9 hours between shifts. Research on the impact of shift work has shown that quick turnaround between shifts comes with similar health risks to overnight or rotating day and night shifts.
So if you are able to have any input into roster design, looking at shifts that rotate gradually later, are not too long, and don’t have quick turnaround, so that there is sufficient time for sleep and other activities between shifts.
How we cope with shift work is in part genetically determined and in part determined by our general health and fitness. As such, people that are unfit or have other troubles with their health will find it much more difficult to tolerate shift work. Therefore, to increase our ability to manage shift work it is important to maintain good general physical and mental health, be fit and active and ensure good nutrition.
Strategies to Improve Alertness at Work: For people working shift work, feeling tired at work can increase the risk of having accidents or making errors at work. There is research on using caffeine for its effect to help people feel more alert in the workplace. Whist it can be an effective strategy and something that is very commonly used by people, caffeine has a long duration of effect. This means that even though it may be helpful at work, once home and trying to sleep caffeine can get in the way of sleeping.
There may be a role for bright light to help with alertness in the workplace. Light, particularly in the blue-green wavelength has an alerting effect and having adequate lighting has been shown to increase alertness for people at work. There is further research going on in this area to better understand what type of lighting, how much lighting and the timing of lighting.
There are also medications that can be used to help with alertness in the workplace and are often used in fatigue-critical situations such as in the military with people performing prolonged operations. However, importantly, whilst research shows that these reduce the amount of sleepiness, people still remained very sleepy even after using medications, so these are not something that necessarily makes it safe to drive or operate equipment, for example if someone is already feeling sleepy.
Strategies to Improve the Adjustment of the Circadian Rhythm: One of the problems with shift work is the rotation and having to adjust the body clock to new shifts. The body clock will adjust to gradual shift changes but if the rotation of shifts is too quick such as between day and night shift within a couple of days, no amount of trying to adjust the body clock using either melatonin or light will be able to keep up with such rapid change. It is like trying to expect to work in Melbourne one day and London the next and then back in Melbourne two days later. Using light therapy and melatonin can, however, help the body clock to adjust to new times more rapidly. The most important factor though in managing the timing with working rotating shifts is making sure everything else in the day fits with the desired shift timing. That is, for example, if you are working late shifts then recognising that it is important to sleep later and take meals later than normal, essentially shifting your whole routine to match with shift times.
Strategies to Help with Sleep at Home: People working shift work commonly have trouble with both getting to sleep and staying asleep. This can be because the opportunity for sleep is shorter and there is more pressure on sleep increasing anxiety around sleep. Also, trying to sleep when the body would normally be awake can also be difficult. It is important to recognise if you are getting overly anxious about sleep and manage these thoughts, as trying too hard to sleep or putting pressure on yourself about sleeping will almost guarantee that sleep will become progressively more difficult.
There may be a role for using sleep aids such as prescription sleeping tablets. I would generally only use these if people were really having difficulty and the amount of sleep they are getting is very short, placing them at increased risk of other health problems or accidents. I’ll also use sleeping tablets in the sort-term if people are becoming increasingly anxious about not getting enough sleep. While sleeping tablets can be effective to help with sleep when doing shift work they can also have problems with carry-over effect, meaning that people feel may actually more tired than they would be otherwise, which in turn can cause problems with performance at work.
Shift work can be difficult to deal with. The keys to minimising the impact of shift work are:
This article was originally published on www.sleephub.com.au on 2/6/15 by Dr David Cunnington.