Shift Work and Its Impact on Health and Productivity

Shift work is not only defined by the time of day the work is performed, but also the regularity of the schedule and the number of hours worked. An irregular work schedule is defined as one that varies from the standard 9am-5pm, and can include evening shifts, night shifts, early morning shifts, and rotating shifts. A study of 394 day and night workers showed that those with irregular schedules felt that their work interfered more with their family, social and leisure activities. This interference can also lead to the workers feeling isolated from friends and family who keep a day working schedule. The number of hours worked is also an important factor, and one that can impact directly on the safety of the worker. This will be discussed later in the paper in relation to shift duration and working at night.

Shift work is a part of modern society that is here to stay, and it involves working hours outside the standard 9am-5pm day. This can include evening or night shifts, early morning shifts, and rotating shifts. Shift work is common in many industries. In the health care industry, for example, hospitals and other facilities must be staffed 24 hours a day. In the manufacturing industry, involving production or heavy machinery, shift work is a key component in ensuring that maximum capacity is reached. However, shift work has its downside. The human body is designed to be awake during the day and asleep at night, and working outside this framework can cause problems with sleep, performance, and health.

The prevalence of shift work

Traditionally, non-standard work hours were associated with low-skilled and low-paying jobs. This is no longer the case. Shift work is becoming more common in many industries. Differences between countries and regions in the organization of work are largely shaped by the development trajectory, culture, institutions, and policies. New Zealand is not isolated from global trends towards greater diversity in work hours and is experiencing growth in shift work and other non-standard work arrangements. For example, the spread of information and communication technologies has enabled work to be organized on a 24/7 basis. One study in Waikato found around a quarter of all companies had employees working outside normal work hours. Information technology companies and health services had the highest proportion of shift workers. Industries with a higher proportion of shift workers tend to be larger and more economically productive. 24-hour manufacturing is declining; it is still a significant employer in New Zealand. The health sector is growing, with nurses, junior doctors, and allied health workers providing round-the-clock care in hospitals and in the community. Other major employers of shift workers in New Zealand are in the primary production and processing sectors, and the hospitality and retail trade. Shift work is also common in Essential Services, such as the Police and Fire Service. The armed forces have long-established work rosters involving continuous operations. High-technology industries, including telecommunications and electricity generation and supply, are usually also manned continuously. The most recent and significant growth in shift work has been in the service sector, particularly information technology and call center operations, due to increased global connectivity and the need to respond to customers in different time zones. In the future, it is likely that more and more companies will seek to exploit the ability to operate on a continuous basis, and this will mean further growth in shift work. The final factor in the changing work hours picture is the pressure on many workers to engage in non-standard work arrangements. Globalization has led some companies to seek to cut costs by outsourcing work to other countries, where the time zone difference enables work to be processed overnight and returned ready for the next workday. This is occurring in New Zealand, and such jobs are sometimes taken up by people working from home and by immigrants seeking to supplement their income. Overall, there is also a growing trend for workers to work longer hours, and one way of doing this is to spread work hours over more days of the week or times of the day.

The challenges faced by shift workers

Social and family life can be difficult to maintain for shift workers, as their work schedules do not coincide with those of their family or friends. This can lead to increased feelings of isolation and a lack of social support, as well as possible marital and family problems. Shift work has been attributed to increased divorce rates and worsening relationships with children, due to the fact that these people are not getting the quality time together that is necessary to sustain these relationships.

Due to the fact that shift workers work at times when the majority of people are asleep, they are at risk of sleep loss and fatigue which can result in decreased alertness, performance and productivity. This is particularly the case for night shift workers, who have been shown to only obtain an average of 4-5 hours sleep in a 24 hour period between night and day sleep, as opposed to the recommended 7-8 hours. Night shift workers are also found to be more susceptible to stomach problems and ulcers, as well as an increased risk of heart disease, and irritable bowel syndrome. These health issues can be attributed to the disruption of the circadian rhythms, as well as an overall poorer diet and lack of exercise, and can have a large impact on work attendance and overall productivity. Shift workers are faced with various challenges that are associated with their work schedules; these challenges include, but are not limited to, the following.

The importance of addressing shift work-related issues

Behavioral and cognitive performance changes have often been associated with the type of shift system worked. The fast rotations and frequently changing shift times of irregular and rotating shift work can disrupt circadian rhythms and thus induce fatigue and sleepiness at times when wakefulness is required. These workers are more susceptible to accidents due to an increase in sleepiness at work and a reduction in sleep duration. Chronic sleep deprivation or the reduction of the opportunity to obtain sleep can lead to decreased performance, cognitive function, and alertness. A decreased performance at work increases the likelihood of errors and accidents. This is why it is important to have the right balance between health and safety and the productivity demands of an industry. Sleep is also an important recovery process. More sleep and better quality sleep have been associated with better health and well-being. A well-known study on insomnia has shown that a minor increase in waking hours can have a significant impact on quality of life. Sleep disorders and sleep deprivation are clearly detrimental to a shift worker's health and can also affect safety and job performance. An exploration into the specific health effects and safety issues pertaining to shift work will aid the understanding of the impact of different interventions on shift workers and will be beneficial for industries aiming to reduce the health risks associated with their workforces.

A deeper understanding of the impact of shift work on health and productivity will provide better knowledge of how it affects those who work on shifts. This knowledge is important for balancing the health and safety requirements of different industries with the need to optimize productivity. Usually, for a worker, a long-term consequence of shift work is the lifestyle changes that are adopted to cope with the effects of working unsocial hours. These lifestyle changes often involve a compromise of health behaviors because they generally will have less time to prepare and eat healthy food, have smaller meals, consume more "fast food" and sugary drinks to help stay awake, and consume more caffeine and/or use alcohol as a sleep aid. These changes in nutrition and meal frequency alter the worker's metabolism and can lead to obesity and the development of other chronic diseases. Shift workers with families are also more likely to suffer from poor mental health, which may, in turn, affect their job performance and safety. The reason for this will be discussed later.

Understanding the Problem

Shift work is defined as any work schedule that falls outside the hours of 7am and 6pm. Rotating shifts involve continuous movement from one period to another (e.g., morning to evening) usually within a week. This irregular method does not allow the body to adjust and can lead to shift work often having the same effects as frequent time zone changes or the desynchronization of internal body clocks from the natural rhythm. This is of considerable significance given the recent classification of circadian rhythm sleep disorders, which are due to alterations of the body's internal sleep-wake schedule and have a distinct medical pathology. Numerous studies have shown that shift workers have an increased risk of various gastrointestinal problems. This is due to the irregular times at which eating occurs as well as disruptions to gastrointestinal motility. Other diseases that have been attributed to shift work are cancers of the breast, colon, endometrium, and prostate. This led to the placement of shift work involving circadian disruption into Group 2A, "probable carcinogen," in the recent classification by the International Agency for Research on Cancer. Peptic ulcers and cardiovascular disease were the first health problems to be linked to shift work and are supported by a meta-analysis and a review. Overall, shift workers have a higher rate of absenteeism, and there is a general consensus that subjective health is poorer among shift workers than day workers.

Night has always followed day, and humans have worked in the daylight hours of the morning and evening throughout history. Only in the past century has there been a transition from predominantly daytime work to patterns of work involving more extended hours and shift work. It is now estimated that one in five workers in the industrialized world are involved in shift work, with a large percentage working irregular shifts. There are a number of reasons why people elect to work in this fashion, with the major reasons being economic or social needs. Unfortunately, the physiological need for sleep and recovery on a daily basis conflicts with the demands of the job, and in many cases, these needs are compromised. This has led to a significant body of research investigating the various effects of shift work on health, sleep, and performance.

The negative effects of shift work on health

Psychological disorders and mood swings are common effects among shift workers. Emotional instability, irritability, depression, anxiety, and a decrease in enthusiasm are feelings often experienced by shift workers. This may have a variety of causes starting with the disruption of social and family life and resulting in a perception of hostility from family and friends. It can lead individuals to feel a sense of estrangement from the greater community due to the lack of social activities and a decrease in mental health. Shift workers often report increasing numbers of arguments and communication breakdowns in their family life and marriages. This is often attributed to fatigue and shift work sleep disorder. This can result in separation and divorce as well as absenteeism and poor work performance. A Finnish study found that the amount of absence from work due to illness lasting 1-3 days and absences of 4 days or more were higher in all age groups among shift workers. Especially among those aged 25-44, shift workers had a 1.8-fold increase in absence of 4 days or more.

Shift workers are reported to suffer from various digestive system disorders and diseases of the gastrointestinal tract. Often, shift workers have little access to workplace facilities providing food of reasonable nutritional quality. This tends to result in irregular eating habits as well as a higher intake of fat and cholesterol, which is responsible for the higher percentage of shift workers developing peptic ulcers. Gastrointestinal disorders occur as the body has difficulty adjusting to a nocturnal eating and work schedule. This can result in symptoms of irritable bowel syndrome and a higher susceptibility to more serious diseases such as irritable colon and diverticulitis. An Australian study found that there was a higher relative risk of 1.37 of developing irritable bowel syndrome for shift workers compared to day workers.

The impact of shift work on sleep patterns

Shift work can have a negative impact on work patterns for several reasons. The most obvious of these is that social and domestic life may be considerably disrupted. This can often result in the inability to sleep during the day and staying awake at night in order to participate in activities with family and friends. Whilst this is understandable in terms of quality of life, it is not conducive to obtaining sufficient sleep and there are considerable drawbacks to sleeping during the day for a night worker. These include increased disturbances from background noise and light, which can reduce the amount and quality of sleep. It has been found that night workers obtain on average one to four hours less sleep in every 24-hour period than their day working counterparts (4). This can result in the accumulation of sleep debt and a constant struggle to 'catch-up' on sleep during days off from work. It is difficult to assess how long it takes an individual to recover from the effects of shift work. In a study by Rosa and Colligan quoted in (2), 50% of rotating shift workers felt that it took at least 1 week to adjust from night shift to day shift but these effects may be more or less pronounced. Speculative evidence suggests that a permanent night shift worker does not fully adapt to a nighttime schedule, even after several years of working nights and this makes it more difficult to be bi-phasic and switch back to a day orientated sleep pattern during periods off work (6).

The consequences of disrupted circadian rhythms

It is also suggested that shift workers are more susceptible to gastrointestinal diseases, as shift work can disrupt the body's metabolism of food, leading to a loss of appetite, indigestion, and bowel disturbances. This is again supported by Rosenthal's findings of increased peptic ulcers and gastritis (22%) in shift workers, compared to day workers (10%). Smith (1996) suggests that the reason for the higher incidence of accidents and injuries in shift workers is due to the decline in psychomotor performance and alertness that is associated with shift work, caused by circadian rhythm disruption. This decline in performance is also a reason why shift work is often associated with having a negative long-term effect on one's career. A study by Point in 1988 found that police officers on the fast rotation shift showed signs of increased neurotic symptoms and mental distress while on the shifts, which then impaired promotion rates and job retention in the long run. This occurs because the officers do not have the same performance and productivity during the shift work, despite efforts to try and shift their career to the night shifts.

Research has shown that there is a clear link between circadian rhythms and physical and mental health. It has been proven that the circadian rhythm is important for the regulation of the sleep/wake cycle, food absorption, and the body's temperature. Disruption to the circadian rhythm by means of shift work can cause a decline in health and productivity (Smith, 1996). Studies have shown a strong relationship between shift work and ill health, with shift workers often reporting a decline in physical health, mental health, and increased fatigue. Rosenthal's study supports these claims with findings of increased reports of fatigue (63%) and mental health decline (58%) in rotating shift workers, compared to day workers who were 15-23%.

Solutions for Shift Workers

After the schedule has been modified, the next step involves developing employee input and involvement in the decision-making process. This likely enhances the sense of control and predictability of work hours, and is likely to enhance the worker's commitment to, and satisfaction with the chosen schedule. The development of expert consensus panels and the use of participatory action research methods are possible means of achieving this goal. Although change to the designated schedule is straightforward when a single work group is involved, this approach may be difficult when there are multiple work groups and interdependent departments within a business or industry. In such circumstances, computer simulation models can be used to analyze the effects of alternative schedules on staffing and coverage, and help identify a best solution for all involved.

The underlying objective in promoting these changes is to foster better alignment between the demands of work and the capacity of the worker. By maximizing the number of hours off between work periods, individuals have a greater opportunity to meet the competing demands of family, social, and community life, and take care of personal business and chores. They also have more time for sleep and recovery. Although many companies have transitioned to schedules involving extended work shifts (i.e. three or four days of 10-12 hour shifts followed by several days or nights off), there is evidence that shorter shift duration enhances alertness and performance, and reduces risk of accidents and injury. This has led to efforts to develop and analyze schedules involving more frequent changes from work to days off. An example is the Panama schedule involving two or three 12-hour shifts followed by four days off.

One of the most promising approaches to prevention of and coping with the demands of shift work is through the development of interventions targeting improved adaptation. Managed change in the shift schedule has been shown to be the single most effective approach. This includes efforts to increase the time available for sleep and recovery between work periods, decrease the total number of consecutive night shifts, and limit shift duration to eight hours. The underlying principle is that the disruption and displacement of the internal clock is less with schedules that rotate more slowly, in a forward direction, and that provide many days off between the change from nights to days.

Implementing effective scheduling strategies

The main aim of shift scheduling is to allow workers to rotate from working at different times while maintaining 24-hour coverage. This can be achieved in a number of ways with varying effects. Schedules can be organized across the day (e.g. morning, afternoon, and night) or by having a quick rotation where a worker would change from morning shifts in one week to night shifts the following week. Forward rotation (morning to afternoon to night) is generally easier for workers to adjust to than backward rotation. Fixed schedules that do not change are often preferred by workers but do not allow equal access to preferred shift times and also do not cater for events that may require a temporary change of shift. A more recent approach to shift scheduling involves using fast algorithms to generate personalized schedules for workers while accounting for many complex constraints. This approach has been shown to have positive effects on worker alertness and performance as well as reducing stress and fatigue due to work-family conflicts. An example of this is a recent implementation of a self-scheduling web application for hospital nurses that has been shown to greatly improve sleep levels and off-shift alertness.

Providing adequate rest and recovery periods

The shortest and easiest solution to the problem of reduced recovery because of the clockwise rotating shift system is to reverse the direction of rotation. This would provide the same number of rest days in between work shifts (in the case of fast rotation) or more rest days than work days (in the case of slow rotation), and the direction of rotation is always forward in relation to the following off days, allowing a more adequate duration of recovery.

It has also been mentioned that a marked reduction in recovery efficacy occurred when subjects worked at night on their final transition to the first off period [26]. This is an important point since it has been demonstrated that the final night shift in a block of nights is much more difficult to adjust to for night workers, sometimes taking the whole off period for full adaptation to occur. The Circadian Theory suggests that recovery would be maximized if a phase angle close to 0 is maintained between the wake time on the final day of the work period and the wake time on the first recovery day [17]. Adaptation rate is much faster and recovery more extensive when the circadian systems are aligned to the same external phase. This would indicate that assignment to specific shift times should take into account the circadian phase positioning in order to maximize recovery between shift periods, and avoid sleep deprivation.

Comments:

The simplest solution to the problem of reduced recovery effectiveness due to shift work is to stop working shifts. The reasons for reducing recovery are to have less time off work and more days of match-up with the rest of society which may help to combat social isolation. Step-down re-entrainment is a technique that will help shift workers to re-adapt from the shift system back to a permanent day worker in such a way that their circadian systems are realigned to a day oriented sleep-wake cycle. This will be covered in a later section when discussing the possibility of a system fast or slow rotation.

Promoting healthy lifestyle habits for shift workers

- Promoting shifts that rotate forward, through morning, afternoon, and night shift, can reduce the amount of disruption employees experience in their biological and social lives. This may be a more family-friendly approach to shift work. When circadian adaptation is not possible, frequent rotation provides more frequent opportunities to adjust and may reduce the likelihood of the health and social problems associated with specific shifts. A rapidly rotating shift (i.e. one that changes from morning to afternoon to night shift in 2-3 days) can be extremely fatiguing because it forces a quick transition of the worker's internal clock. Forward rotation (morning-afternoon-night) is better tolerated than backward rotation, but the speed of rotation can be adapted to ease the transition to the new shift. An 8-hour shift schedule provides two transitions per 24-hour day, and consequently, it results in the fastest rate of rotation. A slower rotation is associated with less sleep disturbance, less fatigue, and better adaptation.

- Providing workers with more consecutive days off between rotation will allow for more time to recover from the previous shift pattern and have downtime before beginning the next rotation. This will enable shift workers to participate in social and family activities and increase meaningful time off work, in turn improving their overall quality of life. In situations where 24-hour/7-day coverage must be maintained, additional staff will facilitate the use of longer changeovers between rotations. An ongoing participative process involving the workers in the design of the roster is the most preferred way to increase worker input. When designing a roster, note that forward rotation itself allows for easier adaptation and better health for shift workers, so any changes to the roster that allow for easier transition to the new shift are beneficial.

The Role of Armodafinil and Modafinil

The primary objective of shift work is to guarantee continuous and uninterrupted application of effort among healthcare employees. Medications such as modafinil and armodafinil are recommended to accomplish this goal. Dual placebo-controlled studies showed that modafinil (Provigil) is effective in the treatment of somnolence and fatigue in 82 medical workplaces and 86 emergency medicine residents. Seventy-six percent of the modafinil arm were "much improved" compared to 38% for the placebo arm. The greatest degree of improvement was for overall quality of life and ability to stay awake, with about a 35% difference between drug and placebo. Physicians who were given the medication showed no difference in their performance during the day and had no difficulty sleeping at night. This study demonstrates that modafinil is effective in improving alertness and cognitive function in physicians working night float schedules. Randomized control trials also showed that armodafinil treatment of 150 mg for emergency medicine residents moderated fatigue on night shifts, and improved psychomotor speed and accuracy, working memory, and executive function after the night shift. Measures taken for simulating night shift conditions found that medication increased the number of attempts before a mistake and math calculation speed compared to the placebo with minimal effects on diurnal (daytime) cognition and sleep of the residents. These studies collectively demonstrate that modafinil and armodafinil can improve alertness and cognitive function while minimizing impairment of daytime sleep.

Overview of Armodafinil (Armod) and its benefits

It is indicated that Armodafinil significantly improves wakefulness in patients with excessive sleepiness associated with these various sleep disorders, as the dose was found to be effective when compared with a placebo in two 12-week clinical trials involving patients with chronic or acute SWSD. The dose was started at 150mg and increased to 250mg if the initial dose was not effective. The higher doses more consistently produced improvement in wakefulness throughout the day. In both of these trials, there was clear evidence of improvement in wakefulness as measured by the maintenance of wakefulness test at all doses compared with placebo. This evidence is very similar to that observed in modafinil, which suggests that Armodafinil is equally efficacious in improving wakefulness in patients with sleep disorders characterized by excessive sleepiness.

Armodafinil is the active isomer of modafinil, which is a widely used wakefulness-promoting agent. While the exact mechanism of Armodafinil is unknown, it is suggested that its efficacy is similar to that of modafinil. It is used to improve wakefulness in patients with excessive daytime sleepiness associated with obstructive sleep apnea/hypopnea syndrome, shift work sleep disorder, and narcolepsy.

Introduction to Armodafinil (Artvigil), Nuvigil, and Modafinil (Modalert 200mg)

Armodafinil (Artvigil) is the purified, longer lasting enantiomer of racemic Modafinil. Data from the usual animal and adult population trials show that Armodafinil has linear kinetics; its R-enantiomer is usually cleared more quickly than the S-enantiomer which leads to the R-enantiomer providing the primary active Modafinil-eliminated moiety circulating in plasma. Armodafinil is produced and is available for many other brands and generic- although Artvigil is the most known and widely used at a cheap price. Although Armodafinil has not been approved by the FDA for the treatment of jet-lag, it has been widely used by the military in combat- to give soldiers an edge when needing to operate with low amounts of sleep and/or while fighting in other time zones.

Nuvigil (armodafinil) is the "enantiopure" form of Modafinil. Essentially, when you ingest Modafinil, your body metabolizes it into an equal mixture of both R-Modafinil and S-Modafinil. Nuvigil only contains R-Modafinil and has been said to have a slightly cleaner feel (although modulation of the various neurotransmitters will still be an overall similar effect). Oftentimes, patients will take Nuvigil and feel that it is not as strong or potent as Modafinil. This is due to the fact that Modafinil is an equal mixture of both enantiomers, and the user is only receiving the R-enantiomer when taking Nuvigil. Prices for Nuvigil are high, and because it is a newer drug, no generic alternatives are available.

Exploring the benefits of Provigil (Generic Armodafinil) and Waklert

The significant benefits of Provigil (Generic Armodafinil) and Waklert are less adverse effects than traditional stimulants such as amphetamines, and more sustained effect with less 'rebound somnolence' when the medications are stopped. This makes them potentially more useful than older stimulants. Modafinil can be used in the same way. Adverse effects of these newer medications are usually minor. The most common side effects are headaches and nausea, but they are generally mild and tend to decrease over time. More serious rashes have been documented but are very uncommon. Because of the chemical similarity between Armodafinil and Modafinil, the side effect profile of the two drugs is similar. However, because Armodafinil is a more potent psychostimulant, more serious side effects may potentially be induced. Both medications are also significantly more expensive than traditional stimulants, and on average, more expensive than Armodafinil.

Most traditional stimulants for excessive sleepiness such as methylphenidate or the amphetamines and their derivatives affect the brain's limbic system. Stimulants increase the release of the monoamine transmitters (noradrenaline, dopamine and in some cases serotonin) by blocking reuptake to the presynaptic neuron. This leads to an increase in mood, attentiveness, and arousal. These traditional forms of psychostimulation can sometimes lead to overactivity, anxiety and euphoria. Effects on the sleep/wake cycle are very varied, depending on drug half-life. In some cases, the medication can prolong the time taken to fall asleep (increasing sleep latency) and reduce the total time asleep. High doses of stimulants taken in the afternoon may also hinder the 'recovery' sleep that shift workers aim to have before working a late or night shift.