Shift Worker Health and Safety

Fatigue, sleep deprivation, stress and even ‘shift paralysis’ are all present
Publish Date: Monday, October 24, 2005
Author: Carolyn Schur

Practising HR in an organization with shift work has the usual elements — hire, train, pay, discipline, terminate. But it also has an added concern: shift work exposes employees to circumstances that increase levels of health and safety risk.

Human beings are designed to be day-functioning. Physiology predisposes people to sleep at night when it is dark and to be alert in the daytime. Shift work that requires night work causes staff to work against natural physiology. Working against natural physiology increases the potential for physical and emotional stress because the body has to adapt to circumstances for which it was never designed.

As well, because the body was never designed for sleeping in the daytime, most shift workers find that they are more fatigued and sleep-deprived than those who sleep regularly at night. (Though in today’s fast-paced society, sleep deprivation is becoming a concern for all employees.)

Shift work also requires rotating through shifts with start and end times that vary throughout the week. This constant change threatens an employee’s sense of comfort and control and causes stress. Constantly changing schedules also make it difficult to establish regular sleep habits. As a result, shift workers get less quality and quantity of sleep regardless of the shift they are on.

Even in circumstances where night work is not required, there are a variety of day and evening shifts that cause disruption to personal and family lives and result in employees having higher levels of stress. It also happens that many employees who work extended day shifts do so to accommodate other personal and family needs; they may actually be working double shifts and hence experiencing higher levels of fatigue.

In addition to the higher levels of stress and fatigue experienced by most shift workers, there are a number of safety risks. Because people experience their highest levels of sleepiness during the night, there is an increase to the potential for accidents and errors. This has been seen in major accidents in Canada and throughout the world in recent years.

Though employers understand how falling asleep on the job can be dangerous, they often fail to recognize that it is the impairment caused by sleepiness or cognitive fatigue that is equally dangerous. When people are sleepy or cognitively impaired, their vigilance, reasoning and judgment suffer. Yet these are precisely the skills and behaviours that are required to keep workers safe.

An additional danger is that once impaired, people become poor judges of their own level of impairment. Think of someone at a social event who has had too much alcohol. If you were to suggest the person should not drive, they would beg to differ, even as they walk from side to side and are unsure where their car or keys are.

The same holds true for those impaired by sleepiness and fatigue. They may believe they are “fine,” yet the minute they are behind the wheel of a vehicle, their cognitive skills fail them and they are overcome by sleep. In fact, they might be asleep and not even know it.

Shift workers, particularly those who work at night, regularly report incidents of “shift paralysis.” Unlike those subject to sleepiness, these employees are fully awake and aware of their surroundings, yet they are unable to move one or more of their limbs. This is an example of the brain defending itself when it is fatigued and no longer able to function at capacity. Unable to continue receiving information and sending messages to the various muscles, it simply shuts down, and after a brief respite, it gets on with the job again.

A power engineer once experienced such an episode. At 7 a.m., at the end of a night shift, he was alerted to a problem with one of the boilers. He recognized that this was a call to immediate action, yet he could not move. The paralysis lasted about a minute, but in these circumstances, that minute meant that the situation got far more out of control than it should have.

In spite of the risks associated with sleepiness and fatigue at work, it is actually on the drive home after the night shift that shift workers are most at risk. Unfortunately, after having been awake all night, sleepy workers get into their warm, comfortable vehicles where they are sedentary and the roads are mostly straight and smooth, and sleep overcomes them. In the best of circumstances, they drive into the ditch, but frequently, they cause accidents that kill themselves and others.

The stress and fatigue associated with shift work also affect the health of shift workers. It is not uncommon for shift-work workplaces to have an average of 14 sick and absent days per employee per year. This compares to seven or eight in a 9-to-5 workplace. Shift workers are more susceptible to colds and flus and also have higher rates of cardiovascular, gastrointestinal and autoimmune conditions. Shift workers also tend to have poorer lifestyle and diet habits. They smoke more and exercise less, which obviously affects their health.

Sleep disorders like sleep apnea, insomnia and restless legs syndrome are getting much more attention these days, but they present a double danger for shift workers who are already suffering from a lack of sleep quality and quantity as a result of their shift schedules. A sleep disorder further compromises sleep and puts health in even greater jeopardy.

Women who are pregnant are also at greater risk when doing shift work. Studies have found that shift-working women have higher rates of miscarriage and low weight births.

Another concern for the health of shift workers involves exposure limits. Currently, exposure levels are established on the assumption of eight hours of exposure. Yet shift schedules regularly require working 10, 12 or more hours at a time. It is not known if having days off between shifts is sufficient to compensate for the additional exposure.

How to reduce the level of risk

Management practices are key in improving the health and safety of shift workers. For example, reducing the need for overtime is very beneficial in reducing both the stress and fatigue load of employees. In the current economic conditions, it may not be possible to find all the staff needed or even the financial capacity to ensure sufficient staffing. However, be open to looking at overtime levels and what strategies may be possible to alleviate some of the consequences.

Another key element is the extent to which the organization operates as a shift-work workplace or a regular 9-to-5 workplace with add-on shifts. If it is the latter, employees may be required to attend meetings and training sessions on their days off or after a night shift. This compromises sleep and health and increases their fatigue load.

Though wellness programs benefit all employees, they need to be emphasized for shift workers. Because they will be exposed to the additional stress and fatigue of shift work, it is essential that they be as healthy as possible to face these challenges. Smoking is an example of a behaviour that compromises health, but it also compromises one’s ability to get quality sleep. Exercise, on the other hand, can improve deep sleep so it should be encouraged for the usual health reasons as well as for improving sleep.

By far, the most effective strategy for reducing the health and safety risk of shift workers is to implement best practice schedules. In Canada, many organizations still employ intermediate length schedules, which require between three and seven of the same shift in a row. These are universally considered to be the most tiring schedules. There is no one perfect schedule, but there are many examples of schedules that meet business needs and the sleep and personal needs of employees. Best practice schedules, by design, reduce the potential for stress and fatigue and lead to improved safety and health outcomes.

Having said all this, one needs to note that not all shift workers are equally subject to the health concerns noted above. You’re probably familiar with many employees who have been shift workers for many years and are still healthy with no sleep problems. One could quite easily conclude that those who are “suffering” — that is, missing work or succumbing to various illnesses more frequently — must just be whiners and complainers who don’t care about their jobs.

No doubt there are such employees, but at the heart of these differences is adaptability. Some workers are physiologically better adapted to shift work than others. Those who are less well adapted will, unfortunately, be much more susceptible to the negative consequences of shift work and will have higher rates of fatigue and illness.

Knowing this, it is vital that human resource practice include an assessment of employees so that they can be managed toward better health outcomes. As a minimum, human resource strategies should include education on how to protect sleep and get both sufficient quality and quantity of sleep.

Ideally, one would have best practice schedules which would make it easier for all shift workers to adapt. In the absence of such a schedule, one can assign employees to shifts to which they are most adaptable. This requires minimal effort on the part of human resources staff, yet has dramatic results in reducing negative health and safety outcomes.

Managing shift worker health and safety