Work of supermarket cashiers has been explored for several occupational risk factors including magnetic field exposure from the cash register and scanning system (Forssen et al., 2004), exposure to chemicals like Bisphenol A from the handling of receipts (Lu et al., 2013), and the risk of developing a nickel allergy by handling of coins (Gawkrodger, McLeod and Dobson, 2012; Thyssen et al., 2013). A higher risk of bladder cancer is hypothesized to result from lifestyle and fewer opportunities for micturition, prolonging the contact time between the bladder mucosa and any urinary carcinogens that might be present (Colt et al., 2004). However, the majority of research on the occupational health of cashiers has addressed musculoskeletal pain, especially complaints about pain in the upper extremities, shoulders, and back that are supposed to result from biomechanical load from repetitive work (Bonfiglioli et al., 2007; Peppoloni et al., 2016; Sansone et al., 2014; Sansone et al., 2015). Among occupational health problems, musculoskeletal pain in arms, shoulders, knees, legs, and especially in the back is common among workers in many occupations. Specifically, compared to other occupations, reports of musculoskeletal pain are more frequent in cashiers: For instance, in Italian female cashiers musculoskeletal pain in arms and shoulders was recently reported in 46.5% of cashiers but only in 25.5% of a female control group (Sansone et al., 2014). The Global Burden of Disease Study 2013 reported low back pain as the cause of years lived with disability (and neck pain on position four; Vos et al., 2015). The cost of low back pain associated with presenteeism, absenteeism, and work disablement is high: In Switzerland, musculoskeletal pain is a major health problem causing costs of 1.3–3.2% of the gross domestic product (SNF, 2009). Lower back pain is responsible for about 6.1% of the total health care expenditure in Switzerland (Wieser et al. 2011). Not to mention the individual burden on the person itself, including stress at work, family stress and economic stress, which all result in a reduced quality of life (Elfering and Mannion, 2008). Hence, prevention of work-related musculoskeletal pain is a top priority (Elfering, 2006).
Beside repetitive movements, prolonged sitting or standing of cashiers was studied as a risk factor. For instance, in a laboratory experiment with ten cashiers from Dutch retailer environment Lehman, Psihogios and Meulenbroek (2001) found lower muscle activity in the neck and shoulders when standing and using a bi-optic scanner. Yet, sitting is usual for cashiers in Europe (Hinnen et al., 1992) while prolonged standing of cashiers is typical in North America, Asia and Australia (Messing et al., 2005). Frequent short breaks and work rotation between different tasks or at least between cashier desks that allow a change of left/right arm and shoulder function were proven to reduce the risk from repetitive work (Asensio-Cuesta et al., 2012; Rissén et al., 2002). However, Bernard (2005) showed that what characterizes cashiers’ work is not only repetitive manual work but having to manage flows of products and customers. Bernard therefore characterizes cashiers’ worktime often as a compromise that comes out of balancing productivity with human relations – and sometimes the compromise causes conflict (Bernard, 2005). Studies by Lundberg and colleagues show that mental stress and physical effort increase electromyographic activity and musculoskeletal pain (cf., Lundberg et al., 1999). An important step in understanding the link between work demands of cashiers and musculoskeletal pain is to look at work strain as a mediating mechanism. The purpose of the present study is to link emotion work and musculoskeletal pain in cashiers via sleep problems.
In a qualitative study on supermarket cashiers in Israel it became clear that customers and cashiers interact frequently while having complex interaction strategies, and interactions are often stressful (Rafaeli, 1989). In this pioneering study from Israel there was no management rule that addressed interactions between cashiers and customers. Nowadays, in most countries of the Western World management rules about customer interactions oblige cashiers to be friendly – even with impolite customers (Ford, 1995; Grandey, Rupp and Brice, 2015). Such management rules increase the need of emotion work and the experience of emotional dissonance. In face-to-face interactions with costumers displaying required emotions become a part of the job leading to the concept of emotion work. Emotion work (or emotional labour) “should be defined as the psychological processes necessary to regulate organizationally desired emotions” (Zapf, 2002, p. 239). It often has positive effects on well-being, both on the customer side and the employee side (Hülsheger and Schewe, 2011; Zimmermann, Dormann and Dollard, 2011). However, emotion work can instead have negative effects on employees’ well-being, often because of a misfit between emotions showed and emotions felt (Zapf, 2002). Having to show positive emotions that do not fit their felt emotions often results in emotional dissonance (Zapf et al., 2001). Suppression of negative emotions often allows them to persist and increases regulatory effort and may promote a feeling of lack of authenticity (Semmer, Meier and Beehr, 2016). Emotion work is a central demand in supermarket cashiers’ work (Vignon and Scoyez, 2011; Rafaeli, 1989). Among other demands of emotion work in cashiers, such as the requirement to be sensitive to clients’ emotions, emotional dissonance was found to be a strong stressor in cashiers (Zapf, 2002). In self-reports of cashiers, impolite behaviour of customers appears to be the leading source of stress, followed by stress that arises from bad design or function of the computer system or other technical equipment (Kihlstedt and Hägg, 2011). Up to now, emotional dissonance in cashiers was explored as a risk of well-being, but musculoskeletal pain as outcome was not in focus before (Elfering, 2006).
Work strain depicts a physiological, behavioural, and psychological reaction to work demands, threats, and challenges (i.e., stressors such as emotional dissonance) and implies feeling stressed and exhausted (Ganster and Rosen, 2013). Work strain, in turn, corresponds to musculoskeletal pain via mechanisms that elicit muscle tension and induce pain; these are both physical (e.g., stress-induced increase in noradrenalin; Elfering et al., 2008; Elfering et al., 2002; Melin and Lundberg, 1997) and mental (e.g., pain-related beliefs; Elfering et al., 2015). According to the ‘Cinderella Hypothesis’ (referring to Cinderella, who was first to rise and start work and last to end work and rest; Hägg, 1991), the small, low-threshold motor units are always recruited first, before large ones, and they remain activated until the complete relaxation of the muscle. These low-threshold motor units are part of a strain response to stressors, and strain-related increase of noradrenalin probably augments the sensitivity of low-threshold motor units (Melin and Lundberg, 1997; Lundberg and Melin, 2002). Thus, work strain prolongs tension and sensitivity leading to musculoskeletal pain.
Disturbed sleep, as a psychosomatic strain response (see Ganster and Rosen, 2013), might also influence the perception of work. Recently, Reddy and colleagues (2016) found just one night of modest sleep loss to be related to large adverse effects on positive affect and anxiety and, to a lesser extent, negative affect. Impaired sleep was found to interfere with psycho-physiological functions enabling self-control (Motomura et al., 2013). Drawing on the Ego Depletion model, Barnes, Schaubroeck, Huth and Ghumman (2011), within both laboratory and field study settings, found disturbed sleep to be associated with unethical (i.e., morally unacceptable) behaviour due to depleted self-control resources. Similar to ethical behaviour, emotional dissonance – perceived discrepancy between felt emotions and those the employee’s organization requires them to display – demands self-control resources (Diestel, Rivkin and Schmidt, 2015; Zapf and Holz, 2006). In consequence, cashiers with impaired sleep might much more easily be disturbed by an unpleasant situation (Chuah et al., 2010), and even weak emotional stressors might trigger mood deterioration (Minkel et al., 2012) that might lead to emotional dissonance. However, within the scope of stress research, adverse working conditions and their affective consequences might also be associated with disturbed sleep (for a review see Sonnentag, Casper and Pinck, 2016). Evidence shows that strain may arise from the experience of emotional dissonance (Diestel, Rivkin and Schmidt, 2015; Grandey and Gabriel, 2015; Grandey, Rupp and Brice, 2015; Zapf, 2002). Moreover, there is also evidence that strain is related to musculoskeletal pain and the mechanism, i.e., as described by the Cinderella model, can sufficiently explain the link between work strain and musculoskeletal pain in cashiers (Lundberg and Melin, 2002).
As emotional dissonance depletes regulatory resources (Zapf and Holz, 2006), these resources have to be restored. Sleep restores limited regulatory resources facilitating self-control functioning (Barber et al., 2010; Diestel, Rivkin and Schmidt, 2015). On the other hand, sleep regulation seems to be impaired by stressors. The type of dysregulation – such as awakenings (Pereira and Elfering, 2014a) and change of sleep phases – seems to depend on stressor characteristics: Unpredictable and uncontrollable stressors – such as encounters with aggressive customer behaviour – seem to cause the most severe dysregulation (Sanford, Suchecki and Meerlo, 2015; Sonnentag, et al., 2016). A recent systematic review on work stressors that arise from social interaction and sleep found 14 studies (Pereira et al., 2016), 10 of which reported correlations. The weighted mean correlation of these 10 studies was Rho = .21 (CI95 = .12–.31). In addition, a recent longitudinal large-scale study on older adults confirmed that strain mediates the link between weight discrimination experiences and impaired sleep (Vaghela and Sutin, 2016).
In sum, sleep is a special form of recovery that restores stress-drained resources and is at the same time impaired by stress (Åkerstedt, Nilsson and Kecklund, 2009). The neurotransmitters and hormones involved in the stress response are also involved in sleep regulation, and “the interaction between stress and sleep is implicated in a variety of disease processes and psychiatric disorders” (Sanford, Suchecki and Meerlo, 2015: 381). Another recent – however, cross-sectional – large-scale study supported a mediation model in which strain and restricted sleep quality mediated the association between unfairness at work and health complaints (Elfering et al., 2016). Yet, there is evidence that being nagged by pain might lead to impaired sleep as well as some evidence that impaired sleep was adversely associated with pain (Kelly et al., 2011; Lautenbacher, Kundermann and Krieg, 2006). A possible mechanism by which disturbed sleep can cause pain is by enhancing pain sensitivity (Lautenbacher, Kundermann and Krieg, 2006). Disturbed sleep as well as sleep deprivation can decrease pain threshold and were found to produce somatic symptoms (Haack and Mullington, 2005; Lentz et al., 1999; Onen et al., 2001). Recently, based on a large eight-year, longitudinal cohort study with healthy working adults, Agmon and Armon (2014) found evidence that sleep problems precede the onset of musculoskeletal problems. Moreover, Finan, Goodin and Smith (2013) examines the recent prospective and experimental research (beginning from 2005). According to this review, longitudinal studies suggest sleep impairments to be a more reliable predictor of pain than vice versa and experimental studies found sleep disturbance to interfere with key processes of the development and maintenance of chronic pain.
All in all, we expect impolite customer behaviour to be a major stressor in cashiers. Moreover, we hypothesize that emotional dissonance will be positively related to musculoskeletal pain even when other work stressors like the amount of repetitive work movements and prolonged sitting are controlled in analyses (H1). In addition, more intense and frequent emotional dissonance is expected to relate to more prevalent sleep problems, and sleep problems should be positively related to musculoskeletal problems. Hence, sleep problems are suggested to partially mediate the link between emotional dissonance and musculoskeletal pain in cashiers (H2, see Figure 1).
Cashiers from three larger supermarkets were invited to participate. Cashiers received a 10 CHF voucher for participation. Out of 180 questionnaires that were distributed, 109 cashiers responded (participation rate 60.6%). Four questionnaires were filled out incompletely with one or more pages of the questionnaire not filled out. These four participants were excluded from the sample. The remaining 105 cashiers consisted of 103 women and 2 men. The two men were excluded from analysis to avoid bias from unbalanced gender distribution in the sample. Mean age was 41.2 years (SD = 13.7). Only 14.6% of the sample worked full-time, which comprises 42h work per week (Mean percentage of the 42h stint was 50.1%, i.e. a 21h work week). Twenty-two cashiers reported having finished obligatory school as their highest level of education (21.6%). The majority of the sample (61.8%) had completed an apprenticeship including a certificate of higher vocational education and training; 12.7% stated that they had a university-entrance diploma or a degree from a college of education and 3.9% reported having a university degree. Sitting position during a shift was usual (78.6%), while standing was typical for four cashiers (3.9%) and both, sitting and standing while working the cash register was reported by 18 cashiers (17.5%). Mean tenure at the current position was 8.7 years. As the study was conducted in the German-speaking part of Switzerland, all questions were in German. The questionnaire was delivered in paper format in a closed envelope together with a postal envelope for return. The study was conducted in accordance with the requirements for participants as defined by the Swiss Society of Psychology (that is, in accordance with the Declaration of Helsinki) and approved by the local University ethics committee (2014-4-846185). Study participants were provided with information about their rights and were guaranteed anonymity.
To clarify the salience of potentially stressful situations at work an open question was asked “What do you dislike at your cashier job?”. Cashiers had three lines of space to make notes. Emotional dissonance at work was assessed with an item from the Frankfurt Emotion Work Scales (FEWS); Version 3.0 (Zapf et al., 1999). The “emotional dissonance” item addressed the necessity to display emotions that are not genuinely felt. Response options ranged from “very rarely/never” (1) to “very often/constantly” (5). Sleep problems were assessed with a single question from the brief Sleep Standard Evaluation Questionnaire (Aghayev et al., 2010). The question was “How was the quality of your sleep in the last four weeks” with the response options “I had no sleep problems at all” (1) to “I had severe sleep problems” (5). Musculoskeletal pain was assessed with five items (Müller et al., 2008). The items were: “How much pain have you experienced in the following body regions today?” Pain in arms or shoulder (2 items), neck and back pain (1 item), and pain in hip, knee or feet (2). The response format was a five-point Likert scale with no pain (1) to very strong pain (5).
Beside emotional dissonance other physical and mental work demands may relate to sleep and musculoskeletal pain. Therefore change of hand function as an indicator of physical load and information processing demand as indicator of mental demands were added as control variables. In all analyses, percent employment, lack of change of hand function during cashing across a work day (0 = change of hand function, 1 = no change of hand function), BMI and age were included as control variables. With respect to task stressors a single item on information processing demand (“The job requires me to keep track of more than one thing at a time.”) from the Work Design Questionnaire (WDQ, Morgeson and Humphrey, 2006; German version: Stegmann et al., 2010) was included as control variable.
The mediation hypothesis was tested using Hayes’ (2013) bootstrap test for estimation of indirect effects (PROCESS macro for SPSS). The number of bootstrapped resamples was 5000. All analyses were conducted using SPSS 22.0.
Responses to the open question of what cashiers did not like at their job included as most prevalent stressor dealing with impolite customers (reported by 47.6% of cashiers, Figure 2). Prolonged sitting was reported by 8.7%, followed by monotony (7.8%), working time schedule (5.8%), and small cashier boxes (5.8%). Means, standard deviations, estimates of reliability, and zero-order correlations among all study variables are shown in Table 1. More frequent emotional dissonance corresponded to more sleep problems and pain in the neck and back. Sleep problems were significantly related with all indicators of pain. Musculoskeletal pain in arms and shoulders, neck and pain, and pain in the hip, knees and feet were significantly interrelated (r (103) between .36 and .54, p < .001). Pain in arms and shoulders was positively related to age. Pain in hips, knees, and feet corresponded to higher BMI. Higher percent of employment was linked to more neck and back pain.
|1. Emotional dissonance||1||1–5||2.25||1.24||n.a.|
|2. Sleep complaints||1||1–5||2.08||1.00||n.a.||.21*|
|3. Pain in arms and shoulders||2||1–5||1.89||1.08||.74||.14||.38***|
|4. Neck and back pain||1||1–5||2.45||1.26||n.a.||.27**||.40***||.54***|
|5. Pain in hip, knee and feet||2||1–5||1.81||1.07||.80||.03||.19||.36***||.50***|
|8. Percent employment||1||n.a.||50.15||27.65||n.a.||–.09||.07||.10||.23*||.11||.06||–.02|
|9. No change of hand functiona||1||0, 1||0.28||0.45||n.a.||–.01||.21*||.09||.01||.06||–.01||.06||.10|
|10. Information processing demand||1||1–5||3.84||0.93||n.a.||–.08||–.20*||–.13||–.14||.08||.19||–.04||.21*||.04|
In accordance with zero-order correlations, emotional dissonance and pain in arms and shoulders as well as in the hip, knees, and feet were not significantly correlated. Emotional dissonance was a significant predictor of neck and back pain (Figure 3). A model of partial mediation fitted the regression of pain in the neck and back on sleep problems and emotional dissonance (B = .21, SE = .10, CI = .02–.22) and the indirect path explained 13% of variation in neck and back pain.
In the current study, experience of dealing with impolite customer behaviour (reported by 47.6% of cashiers) was a common disliked task referring to this as a salient stressful situation. The rate corresponds well with data from Kihlstedt and Hägg (2011) who found 22 out of 50 cashiers reported interactions with unpleasant, and stressed customer to be stressful. When confronted with impolite customer behaviour cashiers are likely to experience emotional dissonance – they keep showing a positive or neutral emotion towards the customer when they often feel a negative one.
According to the current study, emotional dissonance might be a unique risk factor for neck and back pain and it seems that the risk from emotional dissonance is not limited to the mere experience of this unpleasant customer situation, but has a potential impact on sleep after work is done. In line with other studies, negative social interactions and social relations were found to be related to sleep quality (Elfering et al., 2016; Pereira et al., 2016; Pereira, Meier and Elfering, 2013). The association of sleep problems and musculoskeletal pain was confirmed before in large epidemiologic studies (Aghayev et al., 2010); specifically with respect to back pain (Kardouni, Shing and Rhon, 2016; Shmagel, Foley and Ibrahim, 2016). Thereby, sleep problems may arise as a consequence of musculoskeletal pain (Aghayev et al., 2010), as pain is known to disturb sleep by inducing arousal and triggering the physiological stress reaction (Lautenbacher, Kundermann and Krieg, 2006). On the other hand, these problems may antecede the onset of musculoskeletal pain (Agmon and Armon, 2014), as disturbed sleep enhances pain sensitivity (Lautenbacher, Kundermann and Krieg, 2006).
We started from the assumption that sleep problems anteceded musculoskeletal pain. Thus, the mechanism linking work-related stress and pain is likely to be a lack of sleep-related recovery (Pereira et al., 2016). Negative social experiences at work often cause a “failure to switch off” when away from one’s work (Berset et al., 2011; Sonnentag and Bayer, 2005). Sustained negative psychophysiological arousal potentially impacts sleep quality (Pereira et al., 2016; Sonnentag, et al., 2016) and should be studied in future research on emotion work and musculoskeletal pain in cashiers. According to Geurts and Sonnentag (2006), incomplete recovery is the key process involved with impaired sleep quality as the most important recovery process. Having to follow emotional display rules and experiencing emotional dissonance can be characterized as organizational unfairness (Grandey, Rupp and Brice, 2015). Evidence for the negative association of unfairness with employee health has been confirmed (Robbins, Ford and Tetrick, 2012). In a study conducted by Elovainio et al. (2003), much of the effect of unfairness on health was attributable to sleeping problems. Hietapakka et al. (2013) found psychological distress in nurses, and found that job involvement mediated the association between organizational justice and sleep, while sleeping problems partly mediated the association between organizational justice and performance. In a cross-sectional large-scale study, Elfering et al. (2016) showed that sleep problems mediated the association between unfairness at work and unfairness in private life (and the joint unfairness experienced in both life domains) with health problems.
Yet, longitudinal research recently showed full mediation of the stressor-strain link by perseverative thoughts and a bidirectional stressor-strain relation, i.e., impaired sleep quality predicts increase in work stressors (Pereira et al., 2016; Van Laethem et al., 2015). In other words, the perception of today’s working experiences and behaviour might be influenced by last night’s sleep quality. Barnes and colleagues (2011) found disturbed sleep to be associated with unethical (i.e., morally unacceptable) behaviour due to depleted self-control resources. Sleep is closely linked to emotion regulation (Reddy et al., 2016), and thus disturbed sleep affects reactions to emotional situations (Chuah et al., 2010; Minkel et al., 2012). It interferes with psycho-physiological functions enabling self-control (Barnes et al., 2011; Motomura et al., 2013). Emotional dissonance, however, demands self-control resources (Diestel, Rivkin and Schmidt, 2015; Zapf and Holz, 2006). Thus, disturbed sleep might also lead to the perception of emotional dissonance that might lead to pain.
Along with our results, there is a link between emotional dissonance, disturbed sleep, and neck and back pain, yet the direction needs further investigation. There might be an ongoing cycle starting with either work stress, sleep problems or pain maintaining or even augmenting each other (e.g., Kelly et al., 2011; Lautenbacher, Kundermann and Krieg, 2006). For instance, Diestel and colleagues (2015) found that impaired sleep quality of the previous night enhanced the adverse effect of emotional dissonance on daily well-being. Evidence for reversed causation, i.e. sleep problems increase social stressors, is growing, as shown in the systematic review of Perreira et al. (2016). A recent longitudinal study clearly showed simultaneous presence of both the hypothesized stressor-sleep-strain direction and simultaneously a reversed influence of sleep on future psychosocial work stressors. In addition, there is evidence that pain also could impair sleep (Kelly et al., 2011; Smith and Haythornthwaite, 2004). For instance, pain during the night could affect sleep quality (e.g., Affleck et al., 1996) and might initiate the cycle too. Thus, a negative downward spiral is a likely risk in cashiers (Törnroos et al., 2017). Future research on a downward spiral is needed.
Prevention efforts so far addressed ergonomic features of the cashier and scanning environment including job rotation (Rissén et al., 2002). According to our results, one potential means of intervention is that emotional dissonance may be reduced when cashiers learn how to improve their deep acting capability when faced with emotional demands, i.e., cashiers learn to change the felt emotion by re-appraising the situation (Hülsheger and Schewe, 2011; Semmer, Meier and Beehr, 2016; Zapf and Holz, 2006). Such a deep acting strategy seems to have more positive effects when service agents view their demands in customer conflict handling as a challenging and important task (Huang et al., 2015) that currently cannot be done with comparable quality by automated systems (Albu, 2016; Ba and Alis, 2016). Indeed, customer conflict handling, including cashiers’ behaviour directed at deterring potential conflict, expertly addressing manifest conflict, and using constructive strategies for conflict management can be characterized as a challenging task (Ndubisi, Malhotra and Wah, 2008). Thereby, emotional display rules can be a barrier for performance in customer conflict handling (Grandey, Rupp and Brice, 2015). Emotional display rules should be changed to enable more authentic cashier behaviour and reduce emotional dissonance, because the demand to handle aggressive customers seems to increase (Nienhaus et al., 2016) and negative spirals in employee-customer interactions become more likely in stressed cashiers (Groth and Grandey, 2011).
A second way to intervene is by improving sleep quality (Pinheiro et al., 2016). Adequate working conditions and leisure time are most important to enable recovery (Geurts and Sonnentag, 2006). Prioritizing sleep for healthy work schedules should be on the agenda for health promotion initiatives (Takahashi 2012). The person-oriented approach to sleep in workers and employees so far includes sleep extension on weekends, especially for those who sleep less than six hours after work days (Kubo et al., 2011), and online sleep training intervention (including mindfulness training) to increase sleep quality after work (Ebert et al., 2015; Thiart et al., 2015). Cashiers with sleep problems could also be trained in using cognitive-behavioural stress-management to improve sleep quality (e.g., Querstret et al., 2016; Richardson and Rothstein, 2008).
The current study is limited with respect to what it can tell us about the processes behind the link between emotional dissonance, sleep, and musculoskeletal pain. Results of cross-sectional studies do allow for many alternative explanations of the observed effects, as reverse causation cannot be precluded (Zapf, Dormann and Frese, 1996). Previous diary research, including actigraphy, however, suggests that work-stress-related activation, sustained after work by perseverative thoughts (worrying) and a lack of detachment from work, is likely to cause the decrease in sleep quality (Pereira and Elfering, 2014b). Cashiers in the study group are representative of a large portion of cashiers in Switzerland who work for a very large retailer group. Nevertheless, differences in musculoskeletal pain between German-, French-, and Italian-speaking parts of Switzerland can not be excluded. Our results needs to be replicated using a larger sample and a longitudinal design. Moreover, future research should account for a possible downward spiral in terms of an ongoing cycle starting with either emotional dissonance, sleep problems or pain. A replication should also rely on assessment of additional task-related and social stressors and resources. The reliance on self-reports might inflate correlations, as response biases (such as acquiescence) influence the assessment of emotional dissonance, sleep problems, and musculoskeletal pain (Semmer, Grebner and Elfering, 2004). The use of sleep actigraphy, for instance, would help to prevent common-method variance (Pereira et al., 2016). Sleep quality is a complex phenomena that comprise several components. By using a single item, sleep quality measurement contains the risk of under- or overestimation, although assessing a global evaluation of a person’s sleep quality might be useful (De Beer, Pienaar and Rothmann, 2014). Rosenzveig et al. (2014) reviewed a similar single item measure of sleep to be appropriate (see also Cappelleri et al, 2009). In addition, emotional dissonance was assessed by single item measure too. The item chosen has good quality and therefore was also included in the “Instrument for Stress-oriented Task Analysis” (ISTA; cf. Kälin et al., 2000). Finally, cashiers from three larger supermarkets were invited to participate, and the response rate seems to be appropriate (Baruch and Holtom, 2008). However, participants who volunteer in this study might not suffer from severe pain or impaired well-being. Especially, a person who developed impaired well-being might quit or might be assigned to less stressful activities, underestimating the impact of work stress (healthy worker effect; Garst, Frese and Molenaar, 2000; Zapf, Dormann and Frese, 1996). In the longer run, such vicious cycles including emotional work demands might result in depression (Vammen et al., 2016).
Task demands but also emotion work challenge health in cashiers. High prevalence of neck and back pain in cashiers might result from frequent negative customer interactions. Rigid emotional display rules in cashiers should be revised (or replaced) in a way that enables more authentic but polite cashier behaviour while facing unkind customers (Grandey, Rupp and Brice, 2015).
The link between emotional dissonance, sleep problems and neck and back pain was supported by empirical data. Emotional dissonance might be a unique risk factor of neck and back pain with sleep problems as a possible underlying mechanism. Yet, results need to be replicated using a larger sample and a longitudinal design before we can draw conclusions about mediation.
The authors have no competing interests to declare.
The research reported in this article was supported by the valuable help of Pascale Widmer in sample recruitment and data collection.
Affleck, G., Urrows, S., Tennen, H., Higgins, P. and Abeles, M. (1996). Sequential daily relations of sleep, pain intensity, and attention to pain among women with fibromyalgia. Pain 68(2): 363–368, DOI: https://doi.org/10.1016/S0304-3959(96)03226-5
Aghayev, E., Sprott, H., Bohler, D., Roeder, C. and Müller, U. (2010). Sleep quality, the neglected outcome variable in clinical studies focusing on locomotor system; a construct validation study. Bmc Musculoskeletal Disorders 11(1): 224.DOI: https://doi.org/10.1186/1471-2474-11-224
Agmon, M. and Armon, G. (2014). Increased insomnia symptoms predict the onset of back pain among employed adults. PLoS One 9(8): e103591.DOI: https://doi.org/10.1371/journal.pone.0103591
Åkerstedt, T., Nilsson, P. M. and Kecklund, G. (2009). Sleep and recovery In: Sonnentag, S., Perrewé, P. L. and Ganster, D. C. eds. Current perspectives on job-stress recovery: Research in occupational stress and well-being. Bingley, UK: Emerald Group Publishing Limited, 7pp. 205–247.
Asensio-Cuesta, S., Diego-Mas, J. A., Cremades-Oliver, L. V. and Gonzalez-Cruz, M. C. (2012). A method to design job rotation schedules to prevent work-related musculoskeletal disorders in repetitive work. International Journal of Production Research 50(24): 7467–7478, DOI: https://doi.org/10.1080/00207543.2011.653452
Ba, A. and Alis, D. (2016). Employee and customer dissatisfaction in response to the automation of hypermarket checkouts: from voice to defection and negligence. Relations Industrielles-Industrial Relations 71(2): 323–349, DOI: https://doi.org/10.7202/1036612ar
Barber, L. K., Munz, D. C., Bagsby, P. G. and Powell, E. D. (2010). Sleep consistency and sufficiency: are both necessary for less psychological strain?. Stress and Health 26(3): 186–193, DOI: https://doi.org/10.1002/smi.1292
Barnes, C. M., Schaubroeck, J., Huth, M. and Ghumman, S. (2011). Lack of sleep and unethical conduct. Organizational Behavior and Human Decision Processes 115(2): 169–180, DOI: https://doi.org/10.1016/j.obhdp.2011.01.009
Baruch, Y. and Holtom, B. C. (2008). Survey response rate levels and trends in organizational research. Human Relations 61(8): 1139–1160, DOI: https://doi.org/10.1177/0018726708094863
Bernard, S. (2005). Cashiers’ worktime: Between a productive and service mentality. Sociologie Du Travail 47(2): 170–187, DOI: https://doi.org/10.1016/j.soctra.2005.03.002
Berset, M., Elfering, A., Lüthy, S., Lüthi, S. and Semmer, N. K. (2011). Work stressors and impaired sleep: Rumination as a mediator. Stress and Health 27(2): e71–e82, DOI: https://doi.org/10.1002/smi.1337
Bonfiglioli, R., Mattioli, S., Fiorentini, C., Graziosi, F., Curti, S. and Violante, F. S. (2007). Relationship between repetitive work and the prevalence of carpal tunnel syndrome in part-time and full-time female supermarket cashiers: a quasi-experimental study. International Archives of Occupational and Environmental Health 80(3): 248–253, DOI: https://doi.org/10.1007/s00420-006-0129-0
Cappelleri, J. C., Bushmakin, A. G., McDermott, A. M., Sadosky, A. B., Petrie, C. D. and Martin, S. (2009). Psychometric properties of a single-item scale to assess sleep quality among individuals with fibromyalgia. Health and Quality of Life Outcomes 7(1): 54.DOI: https://doi.org/10.1186/1477-7525-7-54
Chuah, L. Y. Dolcos, F. Chen, A. K. Zheng, H. Parimal, S. Chee, M. B. B. et al. (2010). Sleep deprivation and interference by emotional distracters. Sleep 33(10): 1305–1313, DOI: https://doi.org/10.1093/sleep/33.10.1305
Colt, J. S. Baris, D. Stewart, P. Schned, A. R. Heaney, J. A. Mott, L. A. Karagas, M. et al. (2004). Occupation and bladder cancer risk in a population-based case-control study in New Hampshire. Cancer Causes & Control 15(8): 759–769, DOI: https://doi.org/10.1023/B:CACO.0000043426.28741.a2
De Beer, L. T., Pienaar, J. and Rothmann, S. (2014). Job burnout’s relationship with sleep difficulties in the presence of control variables: a self-report study. South African Journal of Psychology 44(4): 454–466, DOI: https://doi.org/10.1177/0081246314538249
Diestel, S., Rivkin, W. and Schmidt, K. H. (2015). Sleep quality and self-control capacity as protective resources in the daily emotional labor process: Results from two diary studies. Journal of Applied Psychology 100(3): 809–827, DOI: https://doi.org/10.1037/a0038373
Ebert, D. D. Berking, M. Thiart, H. Riper, H. Laferton, J. A. C. Cuijpers, P. Lehr, D. et al. (2015). Restoring depleted resources: Efficacy and mechanisms of change of an internet-based unguided recovery training for better sleep and psychological detachment from work. Health Psychology 34(Suppl): 1240–1251, DOI: https://doi.org/10.1037/hea0000277
Elfering, A. (2006). Work-related outcome assessment instruments. European Spine Journal 15(1): 32–43, DOI: https://doi.org/10.1007/s00586-005-1044-x
Elfering, A., Grebner, S., Gerber, H. and Semmer, N. K. (2008). Workplace observation of work stressors, catecholamines and musculoskeletal pain among male employees. Scandinavian Journal of Work, Environment & Health 34(5): 337–344, DOI: https://doi.org/10.5271/sjweh.1280
Elfering, A., Grebner, S., Semmer, N. K. and Gerber, H. (2002). Time control, catecholamines and back pain among young nurses. Scandinavian Journal of Work, Environment & Health 28(6): 386–393, DOI: https://doi.org/10.5271/sjweh.690
Elfering, A. and Mannion, A. F. (2008). Epidemiology and risk factors of spinal disorders In: Boos, N. and Aebi, M. eds. Spinal disorders – Fundamentals of diagnosis and treatment. Berlin: Springer, pp. 153–173, DOI: https://doi.org/10.1007/978-3-540-69091-7_6
Elfering, A., Müller, U., Rolli Salathé, C., Tamcan, O. and Mannion, A. F. (2015). Pessimistic back beliefs and lack of exercise: A longitudinal risk study on shoulder, neck, and back pain. Psychology, Health, & Medicine 20(7): 767–780, DOI: https://doi.org/10.1080/13548506.2015.1017824
Elfering, A., Pereira, D., Grebner, S. and Müller, U. (2016). Lack of detachment and impaired sleep connect perceived unfairness with health complaints: A population-based mediation test. Applied Research in Quality of Life, online first, DOI: https://doi.org/10.1007/s11482-015-9430-y
Elovainio, M., Kivimäki, M., Vahtera, J., Keltikangas-Järvinen, L. and Virtanen, M. (2003). Sleeping problems and health behaviors as mediators between organizational justice and health. Health Psychology 22(3): 287–293, DOI: https://doi.org/10.1037/0278-622.214.171.1247
Finan, P. H., Goodin, B. R. and Smith, M. T. (2013). The association of sleep and pain: an update and a path forward. The Journal of Pain 14(12): 1539–1552, DOI: https://doi.org/10.1016/j.jpain.2013.08.007
Ford, W. S. Z. (1995). Evaluation of the indirect influence of courteous service on customer discretionary behavior. Human Communication Research 22(1): 65–89, DOI: https://doi.org/10.1111/j.1468-2958.1995.tb00362.x
Forssen, U. M., Mezei, G., Nise, G. and Feychting, M. (2004). Occupational magnetic field exposure among women in Stockholm County, Sweden. Occupational and Environmental Medicine 61(7): 594–602, DOI: https://doi.org/10.1136/oem.2003.009654
Ganster, D. C. and Rosen, C. C. (2013). Work stress and employee health: A multidisciplinary review. Journal of Management 39(5): 1085–1122, DOI: https://doi.org/10.1177/0149206313475815
Garst, H., Frese, M. and Molenaar, P. (2000). The temporal factor of change in stressor–strain relationships: A growth curve model on a longitudinal study in East Germany. Journal of Applied Psychology 85(3): 417–438, DOI: https://doi.org/10.1037//0021-9010.85.3.417
Gawkrodger, D. J., McLeod, C. W. and Dobson, K. (2012). Nickel skin levels in different occupations and an estimate of the threshold for reacting to a single open application of nickel in nickel-allergic subjects. British Journal of Dermatology 166(1): 82–87, DOI: https://doi.org/10.1111/j.1365-2133.2011.10644.x
Geurts, S. A. E. and Sonnentag, S. (2006). Recovery as an explanatory mechanism in the relation between acute stress reactions and chronic health impairment. Scandinavian Journal of Work, Environment & Health 32(6): 482–492, DOI: https://doi.org/10.5271/sjweh.1053
Grandey, A. A. and Gabriel, A. S. (2015). Emotional labor at a crossroads: Where do we go from here? In: Morgeson, F. P. ed. Annual Review of Organizational Psychology and Organizational Behavior. Palo Alto: Annual Reviews, 2pp. 323–349, DOI: https://doi.org/10.1146/annurev-orgpsych-032414-111400
Grandey, A. A., Rupp, D. and Brice, W. N. (2015). Emotional labor threatens decent work: A proposal to eradicate emotional display rules. Journal of Organizational Behavior 36(6): 770–785, DOI: https://doi.org/10.1002/job.2020
Haack, M. and Mullington, J. M. (2005). Sustained sleep restriction reduces emotional and physical well-being. Pain 119(1): 56–64, DOI: https://doi.org/10.1016/j.pain.2005.09.011
Hägg, G. M. (1991). Static work load and occupational myalgia: A new explanation model In: Anderson, P., Hobart, D. and Danoff, J. eds. Electromyographical kinesiology. Amsterdam: Elsevier Science Publishers, pp. 141–144.
Hietapakka, L. Elovainio, M. Heponiemi, T. Presseau, J. Eccles, M. Aalto, A. M. Sinervo, T. et al. (2013). Do nurses who work in a fair organization sleep and perform better and why? Testing potential psychosocial mediators of organizational justice. Journal of occupational health psychology 18(4): 481–491, DOI: https://doi.org/10.1037/a0033990
Hinnen, U., Laubli, T., Guggenbuhl, U. and Krueger, H. (1992). Design of check-out systems including laser scanners for sitting work posture. Scandinavian Journal of Work, Environment & Health 18(3): 186–194, DOI: https://doi.org/10.5271/sjweh.1589
Huang, J. L., Chiaburu, D. S., Zhang, X. A., Li, N. and Grandey, A. A. (2015). Rising to the challenge: Deep acting is more beneficial when tasks are appraised as challenging. Journal of Applied Psychology 100(5): 1398–1408, DOI: https://doi.org/10.1037/a0038976
Hülsheger, U. R. and Schewe, A. F. (2011). On the costs and benefits of emotional labor: A meta-analysis of three decades of research. Journal of Occupational Health Psychology 16(3): 361–389, DOI: https://doi.org/10.1037/a0022876
Kälin, W., Semmer, N. K., Elfering, A., Dauwalder, J.-P., Tschan, F., Heunert, S. and Crettaz von Roten, F. (2000). Work characteristics and well-being of Swiss apprentices entering the labor market. Swiss Journal of Psychology 59(4): 272–290, DOI: https://doi.org/10.1024//1421-0126.96.36.1992
Kardouni, J. R., Shing, T. L. and Rhon, D. I. (2016). Risk factors for low back pain and spine surgery a retrospective cohort study in soldiers. American Journal of Preventive Medicine 51(5): E129–E138, DOI: https://doi.org/10.1016/j.amepre.2016.06.005
Kelly, G. A., Blake, C., Power, C. K., O’keeffe, D. and Fullen, B. M. (2011). The association between chronic low back pain and sleep: a systematic review. The Clinical journal of pain 27(2): 169–181, DOI: https://doi.org/10.1097/AJP.0b013e3181f3bdd5
Kihlstedt, A. and Hägg, G. M. (2011). Checkout cashier work and counter design – Video movement analysis, musculoskeletal disorders and customer interaction. International Journal of Industrial Ergonomics 41(3): 201–207, DOI: https://doi.org/10.1016/j.ergon.2011.01.006
Kubo, T., Takahashi, M., Sato, T., Sasaki, T., Oka, T. and Iwasaki, K. (2011). Weekend sleep intervention for workers with habitually short sleep periods. Scandinavian Journal of Work, Environment and Health 37(5): 418–426, DOI: https://doi.org/10.5271/sjweh.3162
Lautenbacher, S., Kundermann, B. and Krieg, J. C. (2006). Sleep deprivation and pain perception. Sleep Medicine Reviews 10(5): 357–369, DOI: https://doi.org/10.1016/j.smrv.2005.08.001
Lehman, K. R., Psihogios, J. P. and Meulenbroek, R. G. J. (2001). Effects of sitting versus standing and scanner type on cashiers. Ergonomics 44(7): 719–738, DOI: https://doi.org/10.1080/00140130119569
Lentz, M. J., Landis, C. A., Rothermel, J. and Shaver, J. L. (1999). Effects of selective slow wave sleep disruption on musculoskeletal pain and fatigue in middle aged women. The Journal of Rheumatology 26(7): 1586–1592.
Lu, S.-Y., Chang, W.-J., Sojinu, S. O. and Ni, H.-G. (2013). Bisphenol A in supermarket receipts and its exposure to human in Shenzhen, China. Chemosphere 92(9): 1190–1194, DOI: https://doi.org/10.1016/j.chemosphere.2013.01.096
Lundberg, U. Dohns, I. E. Melin, B. Sandsjo, L. Palmerud, G. Kadefors, R. Parr, D. et al. (1999). Psychophysiological stress responses, muscle tension, and neck and shoulder pain among supermarket cashiers. Journal of Occupational Health Psychology 4(3): 245–255, DOI: https://doi.org/10.1037/1076-89188.8.131.52
Lundberg, U., Melin, B. and Linton, S. (2002). Stress in the development of musculoskeletal pain In: Avenues for the prevention of chronic musculoskeletal pain and disability. Amsterdam: Elsevier Science, pp. 165–179.
Messing, K., Fortin, S., Rail, G. and Randoin, M. (2005). Standing still: Why orth American workers are not insisting on seats despite known health benefits. International Journal of Health Services 35(4): 745–763, DOI: https://doi.org/10.2190/BNFW-LRKF-NLVB-K5V5
Minkel, J. D. Banks, S. Htaik, O. Moreta, M. C. Jones, C. W. Dinges, D. F. et al. (2012). Sleep deprivation and stressors: Evidence for elevated negative affect in response to mild stressors when sleep deprived. Emotion 12(5): 1015–1020, DOI: https://doi.org/10.1037/a0026871
Morgeson, F. P. and Humphrey, S. E. (2006). The Work Design Questionnaire (WDQ): Developing and validating a comprehensive measure for assessing job design and the nature of work. Journal of Applied Psychology 91(6): 1321–1339, DOI: https://doi.org/10.1037/0021-9010.91.6.1321
Motomura, Y. Kitamura, S. Oba, K. Terasawa, Y. Enomoto, M. Katayose, Y. Mishima, K. et al. (2013). Sleep debt elicits negative emotional reaction through diminished amygdala-anterior cingulate functional connectivity. PLoS One 8(2): e56578.DOI: https://doi.org/10.1371/journal.pone.0056578
Müller, U. Taenzler, K. Buerger, A. Staub, L. Tamcan, O. Roeder, C. Trelle, S. et al. (2008). A pain assessment scale for population-based studies: Development and validation of the pain module of the Standard Evaluation Questionnaire. Pain 136(1–2): 62–74, DOI: https://doi.org/10.1016/j.pain.2007.06.014
Ndubisi, N. O., Malhotra, N. K. and Wah, C. K. (2008). Relationship marketing, customer satisfaction and loyalty: a theoretical and empirical analysis from an Asian perspective. Journal of International Consumer Marketing 21(1): 5–16, DOI: https://doi.org/10.1080/08961530802125134
Nienhaus, A., Drechsel-Schlund, C., Schambortski, H. and Schablon, A. (2016). Violence and discrimination in the workplace. Bundesgesundheitsblatt – Gesundheitsforschung – Gesundheitsschutz 59(1): 88–97, DOI: https://doi.org/10.1007/s00103-015-2263-x
Onen, S. H., Alloui, A., Gross, A., Eschallier, A. and Dubray, C. (2001). The effects of total sleep deprivation, selective sleep interruption and sleep recovery on pain tolerance thresholds in healthy subjects. Journal of Sleep Research 10(1): 35–42, DOI: https://doi.org/10.1046/j.1365-2869.2001.00240.x
Peppoloni, L., Filippeschi, A., Ruffaldi, E. and Avizzano, C. A. (2016). A novel wearable system for the online assessment of risk for biomechanical load in repetitive efforts. International Journal of Industrial Ergonomics 52: 1–11, DOI: https://doi.org/10.1016/j.ergon.2015.07.002
Pereira, D. and Elfering, A. (2014a). Social stressors at work, sleep quality and psychosomatic complaints – A longitudinal ambulatory field study. Stress & Health 30(1): 43–52, DOI: https://doi.org/10.1002/smi.2494
Pereira, D. and Elfering, A. (2014b). Social stressors at work and sleep quality on Sunday night – The mediating role of psychological detachment. . Journal of Occupational Health Psychology 19(1): 85–95, DOI: https://doi.org/10.1037/a0034928
Pereira, D., Gerhardt, C., Kottwitz, M. U. and Elfering, A. (2016). Occupational sleep medicine: Role of social stressors In: Pandi-Perumal, S. R., Narasimhan, M. and Kramer, M. eds. Sleep and psychosomatic medicine. 2nd ed. Basingstoke, UK: Taylor & Francis (CRC Press), pp. 57–84, DOI: https://doi.org/10.1201/b20221-6
Pereira, D., Meier, L. L. and Elfering, A. (2013). Short-term effects of social exclusion at work and worries on sleep. Stress & Health 29(3): 240–252, DOI: https://doi.org/10.1002/smi.2461
Pinheiro, M. B. Ho, K. K. Ferreira, M. L. Refshauge, K. M. Grunstein, R. Hopper, J. L. Ferreira, P. H. et al. (2016). Efficacy of a sleep quality intervention in people with low back pain: Protocol for a feasibility randomized co-twin controlled trial. Twin Research and Human Genetics 19(5): 492–501, DOI: https://doi.org/10.1017/thg.2016.67
Querstret, D., Cropley, M., Kruger, P. and Heron, R. (2016). Assessing the effect of a cognitive behaviour therapy (CBT)-based workshop on work-related rumination, fatigue, and sleep. European Journal of Work and Organizational Psychology 25(1): 50–67, DOI: https://doi.org/10.1080/1359432X.2015.1015516
Rafaeli, A. (1989). When cashiers meet customers – an analysis of the role of supermarket cashiers. Academy of Management Journal 32(2): 245–273, DOI: https://doi.org/10.2307/256362
Reddy, R., Palmer, C. A., Jackson, C., Farris, S. G. and Alfano, C. A. (2016). Impact of sleep restriction versus idealized sleep on emotional experience, reactivity and regulation in healthy adolescents. Journal of Sleep Research, DOI: https://doi.org/10.1111/jsr.12484
Richardson, K. M. and Rothstein, H. R. (2008). Effects of occupational stress management intervention programs: A meta-analysis. Journal of Occupational Health Psychology 13(1): 69–93, DOI: https://doi.org/10.1037/1076-89184.108.40.206
Rissén, D., Melin, B., Sandsjo, L., Dohns, I. and Lundberg, U. (2002). Psychophysiological stress reactions, trapezius muscle activity, and neck and shoulder pain among female cashiers before and after introduction of job rotation. Work and Stress 16(2): 127–137, DOI: https://doi.org/10.1080/02678370210141530
Robbins, J., Ford, M. T. and Tetrick, L. E. (2012). Perceived unfairness and employee health: A meta-analytic integration. Journal of Applied Psychology 97(2): 235–272, DOI: https://doi.org/10.1037/a0025408
Rosenzveig, A., Kuspinar, A., Daskalopoulou, S. S. and Mayo, N. E. (2014). Toward patient-centered care: A systematic review of how to ask questions that matter to patients. Medicine 93(22)DOI: https://doi.org/10.1097/MD.0000000000000120
Sanford, L. D., Suchecki, D. and Meerlo, P. (2015). Stress, arousal, and sleep. Current Topics in Behavioral Neurosciences 25: 379–410, DOI: https://doi.org/10.1007/7854_2014_314
Sansone, V., Bonora, C., Boria, P. and Meroni, R. (2014). Women performing repetitive work: Is there a difference in the prevalence of shoulder pain and pathology in supermarket cashiers compared to the general female population?. International Journal of Occupational Medicine and Environmental Health 27(5): 722–735, DOI: https://doi.org/10.2478/s13382-014-0292-6
Sansone, V. C., Meroni, R., Boria, P., Pisani, S. and Maiorano, E. (2015). Are occupational repetitive movements of the upper arm associated with rotator cuff calcific tendinopathies?. Rheumatology International 35(2): 273–280, DOI: https://doi.org/10.1007/s00296-014-3086-z
Schweizerischer Nationalfonds SNF (2009). Muskuloskelettale Gesundheit – Chronische Schmerzen. Bern: Schweizerischer Nationalfonds SNF. Synthesebericht der Leitungsgruppe [Musculoskeletal health – chronic pain – Report of the SNF steering committee]. Retrieved from http://www.nfp53.ch/files/download/NFP53_Synthesebericht_1004_d.pdf.
Semmer, N. K., Grebner, S. and Elfering, A. (2004). Beyond self-report: Using observational, physiological, and event-based measures in research on occupational stress In: Perrewé, P. L. and Ganster, D. C. eds. Research in Occupational Stress and Well-being. Amsterdam: JAI, 3pp. 205–263, DOI: https://doi.org/10.1016/S1479-3555(03)03006-3 Emotional and physiological processes and positive intervention strategies..
Semmer, N. K., Meier, L. L. and Beehr, T. (2016). Social aspects of work: Direct and indirect social messages conveying respect or disrespect In: Rossi, A. M., Meurs, J. A. and Perrewé, P. L. eds. Stress and Quality of Working Life. Charlotte, NC: Information Age Publishing. 5
Shmagel, A., Foley, R. and Ibrahim, H. (2016). Epidemiology of chronic low back pain in US adults: National Health and Nutrition Examination Survey 2009–2010. Arthritis Care & Research, DOI: https://doi.org/10.1002/acr.22890
Smith, M. T. and Haythornthwaite, J. A. (2004). How do sleep disturbance and chronic pain inter-relate? Insights from the longitudinal and cognitive-behavioral clinical trials literature. Sleep Medicine Reviews 8(2): 119–132, DOI: https://doi.org/10.1016/S1087-0792(03)00044-3
Sonnentag, S. and Bayer, U. V. (2005). Switching off mentally: predictors and consequences of psychological detachment from work during off-job time. Journal of Occupational Health Psychology 10(4): 393.DOI: https://doi.org/10.1037/1076-89220.127.116.113
Sonnentag, S., Casper, A., Pinck, A. S., Barling, J., Barnes, C., Carleton, E. L. and Wagner, D. T. (2016). Job stress and sleep In: Sleep and work: Research insights for the workplace. New York, NY: Oxford University Press, pp. 77–97, DOI: https://doi.org/10.1093/acprof:oso/9780190217662.003.0005
Stegmann, S., van Dick, R., Ullrich, J., Charalambous, J., Menzel, B., Egold, N. and Tai-Chi-Wu, T. (2010). Der Work Design Questionnaire Vorstellung und erste Validierung einer deutschen Version (The Work Design Questionnaire – Introduction and validation of a German version). Zeitschrift für Arbeits- und Organisationspsychologie 54(1): 1–28, DOI: https://doi.org/10.1026/0932-4089/a000002
Takahashi, M. (2012). Prioritizing sleep for healthy work schedules. Journal of Physiological Anthropology 31(1): 6.DOI: https://doi.org/10.1186/1880-6805-31-6
Thiart, H., Lehr, D., Ebert, D. D., Berking, M. and Riper, H. (2015). Log in and breathe out: Internet-based recovery training for sleepless employees with work-related strain – Results of a randomized controlled trial. Scandinavian Journal of Work Environment & Health 41(2): 164–174, DOI: https://doi.org/10.5271/sjweh.3478
Thyssen, J. P., Gawkrodger, D. J., White, I. R., Julander, A., Menne, T. and Liden, C. (2013). Coin exposure may cause allergic nickel dermatitis: a review. Contact Dermatitis 68(1): 3–14, DOI: https://doi.org/10.1111/j.1600-0536.2012.02127.x
Törnroos, M. Hakulinen, C. Hintsanen, M. Puttonen, S. Hintsa, T. Pulkki-Råback, L. Keltikangas-Järvinen, L. et al. (2017). Reciprocal relationships between psychosocial work characteristics and sleep problems: A two-wave study. Work & Stress, : 1–19, DOI: https://doi.org/10.1080/02678373.2017.1297968
Vaghela, P. and Sutin, A. R. (2016). Discrimination and sleep quality among older US adults: The mediating role of psychological distress. Sleep Health 2(2): 100–108, DOI: https://doi.org/10.1016/j.sleh.2016.02.003
Vammen, M. A. Mikkelsen, S. Hansen, A. M. Bonde, J. P. Grynderup, M. B. Kolstad, H. Thomsen, J. F. et al. (2016). Emotional demands at work and the risk of clinical depression: A longitudinal study in the Danish public sector. Journal of Occupational and Environmental Medicine 58(10): 994–1001, DOI: https://doi.org/10.1097/JOM.0000000000000849
Van Laethem, M., Beckers, D. G., Kompier, M. A., Kecklund, G., van den Bossche, S. N. and Geurts, S. A. (2015). Bidirectional relations between work-related stress, sleep quality and perseverative cognition. Journal of Psychosomatic Research 79(5): 391–398, DOI: https://doi.org/10.1016/j.jpsychores.2015.08.011
Vignon, C. and Scoyez, S. (2011). The hidden dimension of emotional labour: tactics to cope with emotional dissonance in French hypermarkets. International Journal of Work Organisation and Emotion 4(2): 113–135, DOI: https://doi.org/10.1504/IJWOE.2011.044593
Vos, T. Barber, R. M. Bell, B. Bertozzi-Villa, A. Biryukov, S. Bolliger, I. Murray, C. J. L. et al. (2015). Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. The Lancet 386(9995): 743–800, DOI: https://doi.org/10.1016/S0140-6736(15)60692-4
Wieser, S., Horisberger, B., Schmidhauser, S., Eisenring, C., Brügger, U., Ruckstuhl, A. and Müller, U. (2011). Cost of low back pain in Switzerland in 2005. European Journal of Health Economics 12(5): 455–467, DOI: https://doi.org/10.1007/s10198-010-0258-y
Zapf, D. (2002). Emotion work and psychological well-being: A review of the literature and some conceptual considerations. Human Resource Management Review 12(2): 237–268, DOI: https://doi.org/10.1016/S1053-4822(02)00048-7
Zapf, D., Dormann, C. and Frese, M. (1996). Longitudinal studies in organizational stress research: a review of the literature with reference to methodological issues. Journal of Occupational Health Psychology 1(2): 145–169, DOI: https://doi.org/10.1037/1076-8918.104.22.168
Zapf, D. and Holz, M. (2006). On the positive and negative effects of emotion work in organizations. European Journal of Work and Organizational Psychology 15(1): 1–28, DOI: https://doi.org/10.1080/13594320500412199
Zapf, D., Seifert, C., Schmutte, B., Mertini, H. and Holz, M. (2001). Emotion work and job stressors and their effects on burnout. Psychology & Health 16(5): 527–545, DOI: https://doi.org/10.1080/08870440108405525
Zapf, D., Vogt, C., Seifert, C., Mertini, H. and Isic, A. (1999). Emotion work as a source of stress. The concept and the development of an instrument. European Journal of Work and Organizational Psychology 8(3): 371–400, DOI: https://doi.org/10.1080/13594329939823
Zimmermann, B. K., Dormann, C. and Dollard, M. F. (2011). On the positive aspects of customers: Customer-initiated support and affective crossover in employee-customer dyads. Journal of Occupational and Organizational Psychology 84(1): 31–57, DOI: https://doi.org/10.1111/j.2044-8325.2010.02011.x