There is extensive research showing that 12-hour shifts, rotating shifts, and unpredictable work schedules are associated with greater risk of chronic health conditions including mental illness, cardiovascular disorders, gastrointestinal disorders, and obesity, and acute conditions, such as pre-term birth.1–10 Yet these schedules are common among workers across many industries, including public safety, manufacturing, and health care. Although employers recognize the potential deleterious effects of unconventional work schedules, they cite a number of arguments in favor of maintaining them, for example, keeping up with customer demand and concerns about profitability or safety that require 24/7 operations. Specifically in manufacturing, the machinery may be too costly to shut down overnight. Additionally, in some cases, employers hear from their employees that they prefer long shifts to maximize days off and pay.11,12
More limited qualitative research pertaining to shift work has demonstrated that shift work drives poor health behaviors and compromises relationships; however, the qualitative literature about the lived experience of shift workers has largely focused on the field of nursing, and is based on interviews and focus groups conducted outside of the United States (US).13–16 Further, previous studies have not broadly examined the impact of shift work on worker well-being. According to the National Institute for Occupational Safety and Health's newly released Framework for Worker Well-Being, there are five domains that contribute to workers’ health and quality of life: workplace physical environment and safety climate (factors that relate to physical and safety features of the work environment); workplace policies and culture (organizational policies, programs, and practices that have the potential to influence worker well-being); health status (aspects of workers’ lives relating to their physical and mental health and welfare); work evaluation and experience (workers’ experiences and evaluations related to the quality of their work life); and home, community, and society (external context of workers’ lives that are situated outside of work but may still influence worker well-being).17
Our objective was to describe the shift work experience of workers in the US manufacturing industry as it relates to the five domains of worker well-being. We chose to focus on manufacturing for several reasons. The industry employs over 12.5 million workers and represents a large share of the US economy (12% of GDP).18 Industry leaders are expecting sizable expansions in production, and hiring a qualified workforce has been described as the industry's biggest challenge.19–21 Additionally, shift work is prevalent in the manufacturing industry, and previous work has shown that manufacturing workers have high rates of short sleep duration.22 Information about how the shift work experiences of manufacturing workers affect well-being can help company leaders better understand the challenges faced by employees, and in turn, may be used to design health and wellness benefits or refine shift work policies.
METHODS
Setting
Data for this study were collected during site visits to four large manufacturing plants (from two participating companies), conducted between September 2017 and January 2018, with the goal of exploring how community health influences worker productivity. Results from the original study, available elsewhere, show that poor community health is associated with greater employee absenteeism, and also contributes to distraction and lapses in safety.23 The four plants were selected for inclusion because they were the largest employers in their respective communities, and the four communities had diverse health profiles. In two plants, managers and hourly workers (ie, assembly line workers) work 12-hour shifts; in two other plants, they work for 8 hours or until they reach a production goal (which may be considerably longer than 8 hours). Hourly workers at three of the plants follow a rotating schedule, meaning that after a certain period of time (bi-weekly, monthly), they change from day shifts to afternoon or night shifts, or vice versa. Managers work day shifts; however, managers were promoted after spending many years as hourly workers on a rotating schedule.
Data Collection
During the site visits, we conducted interviews with plant managers (on average, 11 interviews per plant) and focus groups with hourly workers (two focus groups per plant, with an average of seven participants per focus group). Around 72% of managers and 69% of hourly workers were men. All participants were adults employed in a large manufacturing plant, so there was little variation in socio-economic status among participants.
The interviews lasted, on average, 35 minutes, and the focus groups, 75 minutes. Our semistructured interview protocols, available in the supplementary materials (see PDF, Supplemental Digital Content 1, https://links.lww.com/JOM/A710, Focus Group and Manager Protocols) did not specifically include questions on shift work. All interviews and focus groups were digitally recorded, transcribed verbatim, and uploaded to Atlas.ti, a qualitative software program. The study was approved by Northwestern University's Institutional Review Board, and verbal consent was obtained prior to each interview.
Analysis
We used a combination of deductive codes, based on the interview protocol, and inductive codes based on new concepts that emerged following an initial reading of the transcripts.24 Because the topic of shift work emerged frequently during the interviews and focus groups, we created an inductive code related to the effect of shift work on well-being. After the coding list was finalized, the two team members who conducted the site visits (MM, DF) independently applied the codes to two interview transcripts, and their work was compared and discussed to ensure a common understanding of the coding definitions. A single coder continued to apply the codes to the remaining interview transcripts. All focus group transcripts were double coded by MM and DF, and discrepancies were resolved through discussion.
The Worker Well-Being Framework served as an organizing structure for the results. All passages coded with the “shift work” code were independently reviewed and categorized into one of the five domains of the framework by the three authors. Consensus was reached through discussion. We used thematic analysis, a systematic search for themes, patterns, and repetitions in the data to analyze the data captured within each domain.24 Our findings were reviewed for accuracy by leaders from the two companies.
RESULTS
Managers and hourly workers described shift work as affecting (or potentially affecting) well-being across all five domains of the Worker Well-Being Framework. Because shift work schedules are an example of a workplace policy, we begin with the Workplace Policies and Climate domain, the one domain where respondents were neutral or positive about shift work. Across all other domains, shift work was described as a deterrent to worker well-being. The perceptions of managers and hourly workers were very similar, as managers often recalled challenging experiences working rotating shifts as an hourly worker.
Workplace Policies and Climate
Respondents expressed that they understood the need for companies’ shift work schedules, reporting that shift work and 24-hour operations are necessary to maximize the use of expensive equipment and meet the companies’ production targets. According to one manager, “I understand why we do it and all that stuff is pretty expensive so they want to keep it running all the time.” Several respondents also highlighted the fairness of rotating shifts, noting that all employees share in the burden of overnight hours, rather than allowing only some employees to work a steady day shift. They also noted that working 12-hour shifts results in more days off, allowing more time with family. One hourly worker said, “I prefer the 12 hours because the days off in between are good.” Finally, some respondents mentioned that they are paid more per hour doing shift work, compared to jobs that offered traditional work hours. “They compensate very well for it, I think,” according to one hourly worker.
Physical Environment and Safety Climate
Only a couple of respondents discussed a link between shift work and safety, both noting that shift work causes fatigue, which ultimately may compromise safety. One manager gave an example of a production employee who, towards the end of his 12-hour shift, was badly injured after failing to follow safety protocol. According to the respondent, “this guy admitted he was rushing. He was trying to get it done before he went home. He was right at the end of a 12-hour night shift, his third 12-hour shift in three days.” The manager continued, “I believe we have more accidents on night shift than day shift…People are more tired. When you get tired, you make poor decisions.” Two hourly workers from a different plant also attributed accidents to “[p]eople not getting enough rest” and “sleepiness.”
Health Status
Respondents identified several ways in which shift work compromises physical health. First, 12-hour shifts can be physically exhausting. One hourly worker noted, “Most people can sustain well for 6 to 8 hours, but those last 4 hours in the shift, they tax you.” Another said, “It would be real nice to be able to make it through a day and go home and not just flat die because you’re just in so much pain. Yeah. I mean some days it would be nice. You get off work at 7:00. You get home, get a shower. You don’t feel like even spending time with your family and everything, just because you’re just so physically exhausted.”
Second, numerous respondents described rotating shifts as detrimental to sleep. An hourly worker said, “Everything you read says to get regular sleep. You can’t do that [with rotating shifts].” Respondents noted that shift work wreaks havoc on the body's schedule, and leads to sleep problems, and that it becomes more difficult to rotate as workers age. One manager explained, “They know all the tricks to sleep. The blackout curtains and all that stuff, but when I was 24, if I stayed up all night I’d take a two hour nap and be ready to go. Now if I’m up all night for work, I’m ruined for the next day or two.”
Third, rotating shifts makes it hard to take medication at regular intervals. An hourly worker noted that when you switch from days to nights, you “lose a day” and often medication is skipped. Finally, many respondents noted that both 12-hour days and rotating schedules make it difficult to maintain healthy behaviors. Participants share that they are often too tired or have little time to prepare a healthy meal. A manager said, “I work for twelve, maybe thirteen [hours] because I had a meeting...I barely got seven hours if I go immediately to sleep. I’ll grab that burger and then I will go to sleep and in the morning, I’m grabbing something on the go. I’m not going to have time for a reasonable meal.” Some respondents suggested that night shifts may contribute to alcohol use disorder. One group shared that on nights that they are off, people would resort to going to bars since they are awake and do not have anything else to do.
Additionally, there was an overwhelming expression of shift work contributing to worker stress, particularly with regard to work interfering with family responsibilities. One hourly worker said, “yeah, my biggest stress is holidays, weekends. Because a lot of times I’m here [on] holidays. You would rather be somewhere else, with your family and all, your grandkids...That can be stressful. That can stress you out.” Another hourly worker expressed feeling stress when work conflicts with family events, noting, “now my whole family's gonna be mad because I’m workin’ again.”
Respondents also noted that some manufacturing tasks are rather isolating, and 12-hour shifts can take a toll on mental health. As one manager said, “You’re standing in a box, pretty much by yourself for 12 hours, so if you have anything going on at home outside the plant, you have time to think about that, and you’re all by yourself.”
Work Evaluation and Experience
Although a few respondents identified some benefits of shift work described above, overwhelmingly, respondents said that rotating shifts, and in particular, uncertain schedules, caused tremendous frustration. According to an hourly worker, “The big thing is not knowing when you’re going to go home.” Others said that they have been told they have to work the weekend with just a few days’ notice. “Even on the assembly line, it can be Friday afternoon. They’ll tell you you’re workin’ tomorrow.” These scheduling issues have adverse effects on workers’ ability to fulfill family and social obligations. Finally, an hourly worker summed it up this way, “If you wanna be a family person. It's a tough life.”
In particular, several respondents noted that shift work is largely incompatible with single parenthood. According to one manager, “I don’t know how [single mothers] are able to work out here. They…may come in this evening at 3:00, and they may decide to run production until 1:30 or 2:00 in the morning. And it's not like they have any prior warning. [Their manager] may come around on Wednesday evening or Thursday morning and say, ‘Oh, you’re working this Saturday, and Sunday, also.’ I really don’t know how the single moms do it. That can bring a lot of stress into people's lives when you do that.”
Home, Community, and Safety
As noted above, rotating shifts, 12-hour shifts, and uncertain work schedules often affect respondent's ability to maintain social relationships and fulfill social engagements. One focus group respondent plainly noted, “I stopped making plans a long time ago.” Respondents specifically mentioned a high divorce rate among their peers. One manager said, “Divorce is pretty bad. We see a lot of divorce, just due to the fact that families, especially young couples, you’re away from your family 12 hours, and then when you go home after a 12-hour shift, you just want to sleep.” Another respondent described missing out on much of his son's childhood.
This notion of work interfering with personal lives was expressed consistently during the focus groups and interviews. According to an hourly worker, “That's the difference between a 9:00 to 5:00 job and manufacturing. [We have to] meet numbers. It changes our weekend schedule. Changes the rotating shift. It changes our time with our family. It changes our time with our social life and church and community groups. All those things that you would like to be involved with, because you have a rotating schedule. Sometimes you have this anxious feeling about what would happen on the weekend. That is probably a major part of our stress related to the job.”
DISCUSSION
Results from this qualitative study of the shift work experiences of workers in four US manufacturing plants show that shift work negatively influences well-being across a number of domains. Our results are consistent with numerous studies linking shift work to higher incidence of chronic illnesses and inadequate sleep, and prior studies of nurses showing that shift work is associated with social isolation.2,5,25
Nevertheless, our results are unique in two ways. First, by reporting our findings across the domains of the Worker Well-Being Framework we demonstrated how shift work affects workers’ lives holistically, including their physical, mental, and social well-being. The results suggest that traditional workplace wellness benefits (eg, discounted gym membership, smoking cessation programs), which have a dubious evidence base,26–28 are unlikely to address the challenges associated with shift work. Employers might consider adopting wellness benefits that transcend the boundaries of the traditional workplace, and that can support workers and their families. There are several examples from the US military, for example, on-site child care, commissaries, and leisure and recreation programs to save time and reduce family stress. These examples, while costly, may be feasible for large manufacturers that employ thousands of workers in a single site.
Second, our study is unique in terms of its specific focus on manufacturing. Manufacturing leaders have reported that recruitment is their primary challenge, and the unemployment rate for the industry is at 3%, well below full employment. Employers may have more success recruiting new workers if they implement strategies to reduce the burden associated with shift work.
Encouraging the elimination of shift work was not a goal of our study; indeed, it is largely inevitable in manufacturing and many other industries. Our results showing that the employees were understanding the need for shift work may be heartening to manufacturers. However, there may be ways to organize shift work to minimize the physical, mental, and social strain on workers. For example, some research suggests that it is easier to adjust circadian rhythms when rotating shifts forward (from day to afternoon), rather than backward (from night to afternoon), and workers should have a rest period of at least 24 hours between night shifts.29 Additionally, there are several efforts underway, both legislative and employer initiatives, aimed at minimizing uncertainty in work schedules.30 More work in this area is needed to explore the types of shifts (eg, 8- versus 12-hour shifts, rotating versus static shifts) that are least harmful to worker well-being. This is a good opportunity for corporate and academic partnerships.
More research is also needed to identify the specific strategies that employers may implement to reduce the adverse effects of shift work on worker well-being. Such practical research could lead to widespread adoption of new policies by employers, as they are ultimately responsible for health claims resulting from these adverse effects. Policy makers may also have an interest in these interventions as some research suggests that the cumulative effects of shift work over the working life of an individual are highly detrimental, and in the US, Medicare (the federal health insurance program for Americans age 65 and older) will be the ultimate payer.
The primary limitation of this study was that our data collection instrument was not specifically designed to capture perspectives on shift work. However, the process of inductive coding and thematic analysis led us to identify the detrimental effect of shift work as an issue of great concern to our respondents. Our study is also limited in that we included employees from only four large US manufacturing plants. Shift work policies and perceptions of shift work may differ in other settings.
In sum, we found that workers viewed shift work as necessary to the manufacturing industry but detrimental to well-being. To the extent that it is not possible to eliminate shift work schedules, then employers should consider strategies to mitigate the adverse physical and mental health effects of unconventional shift work, for example, flexibly scheduled on-site childcare. More research to identify practical interventions is needed and partnerships among researchers and industry may be beneficial in facilitating that research.
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