Sleep health interventions for managing mental health in shift workers: A systematic review

Sleep health interventions for managing mental health in shift workers: A systematic review | medRxiv /* */ /* */ <!-- <!-- /*! * yepnope1.5.4 * (c) WTFPL, GPLv2 */ (function(a,b,c){function d(a){return"[object Function]"==o.call(a)}function e(a){return"string"==typeof a}function f(){}function g(a){return!a||"loaded"==a||"complete"==a||"uninitialized"==a}function h(){var a=p.shift();q=1,a?a.t?m(function(){("c"==a.t?B.injectCss:B.injectJs)(a.s,0,a.a,a.x,a.e,1)},0):(a(),h()):q=0}function i(a,c,d,e,f,i,j){function k(b){if(!o&&g(l.readyState)&&(u.r=o=1,!q&&h(),l.onload=l.onreadystatechange=null,b)){"img"!=a&&m(function(){t.removeChild(l)},50);for(var d in y[c])y[c].hasOwnProperty(d)&&y[c][d].onload()}}var j=j||B.errorTimeout,l=b.createElement(a),o=0,r=0,u={t:d,s:c,e:f,a:i,x:j};1===y[c]&&(r=1,y[c]=[]),"object"==a?l.data=c:(l.src=c,l.type=a),l.width=l.height="0",l.onerror=l.onload=l.onreadystatechange=function(){k.call(this,r)},p.splice(e,0,u),"img"!=a&&(r||2===y[c]?(t.insertBefore(l,s?null:n),m(k,j)):y[c].push(l))}function j(a,b,c,d,f){return q=0,b=b||"j",e(a)?i("c"==b?v:u,a,b,this.i++,c,d,f):(p.splice(this.i++,0,a),1==p.length&&h()),this}function k(){var a=B;return a.loader={load:j,i:0},a}var l=b.documentElement,m=a.setTimeout,n=b.getElementsByTagName("script")[0],o={}.toString,p=[],q=0,r="MozAppearance"in l.style,s=r&&!!b.createRange().compareNode,t=s?l:n.parentNode,l=a.opera&&"[object Opera]"==o.call(a.opera),l=!!b.attachEvent&&!l,u=r?"object":l?"script":"img",v=l?"script":u,w=Array.isArray||function(a){return"[object Array]"==o.call(a)},x=[],y={},z={timeout:function(a,b){return b.length&&(a.timeout=b[0]),a}},A,B;B=function(a){function b(a){var a=a.split("!"),b=x.length,c=a.pop(),d=a.length,c={url:c,origUrl:c,prefixes:a},e,f,g;for(f=0;f<d;f++)g=a[f].split("="),(e=z[g.shift()])&&(c=e(c,g));for(f=0;f<b;f++)c=x[f](c);return c}function g(a,e,f,g,h){var i=b(a),j=i.autoCallback;i.url.split(".").pop().split("?").shift(),i.bypass||(e&&(e=d(e)?e:e[a]||e[g]||e[a.split("/").pop().split("?")[0]]),i.instead?i.instead(a,e,f,g,h):(y[i.url]?i.noexec=!0:y[i.url]=1,f.load(i.url,i.forceCSS||!i.forceJS&&"css"==i.url.split(".").pop().split("?").shift()?"c":c,i.noexec,i.attrs,i.timeout),(d(e)||d(j))&&f.load(function(){k(),e&&e(i.origUrl,h,g),j&&j(i.origUrl,h,g),y[i.url]=2})))}function h(a,b){function c(a,c){if(a){if(e(a))c||(j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}),g(a,j,b,0,h);else if(Object(a)===a)for(n in m=function(){var b=0,c;for(c in a)a.hasOwnProperty(c)&&b++;return b}(),a)a.hasOwnProperty(n)&&(!c&&!--m&&(d(j)?j=function(){var a=[].slice.call(arguments);k.apply(this,a),l()}:j[n]=function(a){return function(){var b=[].slice.call(arguments);a&&a.apply(this,b),l()}}(k[n])),g(a[n],j,b,n,h))}else!c&&l()}var h=!!a.test,i=a.load||a.both,j=a.callback||f,k=j,l=a.complete||f,m,n;c(h?a.yep:a.nope,!!i),i&&c(i)}var i,j,l=this.yepnope.loader;if(e(a))g(a,0,l,0);else if(w(a))for(i=0;i (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0];var j=d.createElement(s);var dl=l!='dataLayer'?'&l='+l:'';j.src='//www.googletagmanager.com/gtm.js?id='+i+dl;j.type='text/javascript';j.async=true;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-P4HH5NV'); Skip to main content Home About Submit ALERTS / RSS Search for this keyword Advanced Search Sleep health interventions for managing mental health in shift workers: A systematic review Peter Bragge , Jane Burns , Paul Kellner , Monika Allan , David Fitzgerald , Emily Grundy , Alyse Lennox , Talar R. Moukhtarian , Shantha M.W. Rajaratnam , Tracey L. Sletten doi: https://doi.org/10.1101/2025.07.28.25331984 Peter Bragge 1 Monash Sustainable Development Institute Evidence Review Service, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site For correspondence: peter.bragge{at}monash.edu Jane Burns 2 Jane Burns Consulting , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Paul Kellner 1 Monash Sustainable Development Institute Evidence Review Service, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Monika Allan Find this author on Google Scholar Find this author on PubMed Search for this author on this site David Fitzgerald Find this author on Google Scholar Find this author on PubMed Search for this author on this site Emily Grundy 1 Monash Sustainable Development Institute Evidence Review Service, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Alyse Lennox 1 Monash Sustainable Development Institute Evidence Review Service, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Talar R. Moukhtarian 3 Behaviour and Wellbeing Science, Warwick Manufacturing Group, University of Warwick, Lord Bhattacharyya Way , Coventry CV4 7AL, United Kingdom Find this author on Google Scholar Find this author on PubMed Search for this author on this site Shantha M.W. Rajaratnam 4 Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Tracey L. Sletten 4 Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University , Melbourne, Australia Find this author on Google Scholar Find this author on PubMed Search for this author on this site Abstract Full Text Info/History Metrics Supplementary material Data/Code Preview PDF Summary Shift work can reduce sleep duration and quality, increasing the risk of mental health disorders which burden individuals, their families and productivity. This systematic review aimed to identify and characterise studies evaluating a sleep health intervention in shift workers and measuring a mental health outcome. Searching of seven academic databases identified 102 eligible studies. Interventions predominantly evaluated shift rostering (n=39); pharmacological interventions (n=25); and lighting (n=14). Almost half (n=43) of the included studies recruited healthcare workers. Effective sleep interventions for optimising mental health included forward-rotating (day, afternoon, night) shifts, restricting work hours, pharmaceutical agents and lighting interventions. Insights on the findings provided by two experienced shift workers identified relatively low awareness of the link between sleep and mental health, and variation in acceptability and feasibility of interventions between sectors. Business leaders and policymakers should work to increase awareness of sleep health in shift workers and consider tailored implementation of evidence-based interventions. Future research should prioritise under-represented populations, including those outside of the health and manufacturing sectors and in low- and middle-income countries, and consider expanding the evidence base beyond shift design, medications and lighting. 1. Introduction While most people are sleeping, 15-20% of the working population in industrial societies are working across numerous sectors including manufacturing, hospitality services, emergency services and healthcare [ 1 – 3 ]. To provide these goods and services, shift workers often work variable patterns of early morning, afternoon/evening and overnight shifts. Shift work interferes with the human central circadian pacemaker [ 4 ] which promotes alertness during the day and sleepiness at night through the hormonal and nervous systems [ 5 ], for example via the nightly release of the hormone melatonin which facilitates sleepiness [ 4 ]. The human body cannot easily adapt the timing of the circadian pacemaker to the reversed pattern of work and sleep required by night shift [ 5 ]. The subsequent misalignment is associated with reduced quality and duration of sleep during the day and impaired alertness during night shift. These disruptions elevate risk of occupational and road accidents [ 5 ] and carry associated costs to society estimated at over US$50 billion/year for road accidents and US$20 billion/year for workplace accidents [ 6 , 7 ] Additionally, long-term disruptions to the circadian system have been linked to cardiovascular, metabolic, cognitive, reproductive and gastrointestinal disorders and certain cancers [ 3 , 6 ]. Circadian and sleep disturbances have also been associated with increased risk of negative mental health outcomes including depressive symptoms [ 1 , 8 – 10 ] and adverse impacts on social interaction, recreation and other ‘everyday’ activities. These impacts affect quality of life [ 1 , 6 ], further compromising mental health. Shift work therefore contributes disproportionately to the overall global burden of mental disorders, which make up over 14% of the global of burden of disease [ 1 ]. The adverse mental health impacts of working non-standard work hours highlight the need for interventions addressing sleep health in shift workers. These include pharmacological interventions [ 11 ], psychological therapies such as cognitive behavioural therapy (CBT) [ 12 ], and changes to the physical environment such as light therapy [ 13 ]. Research examining such interventions measures a range of outcomes including numerous measures of sleep quality and duration, productivity, cardiovascular and hormonal parameters. Although some studies also collect mental health data, mental health is often one of many outcomes examined in research examining sleep health interventions for shift workers. Therefore, the aim of systematic review was to comprehensively examine the effect of sleep health interventions for managing mental health in shift workers. 2. Methods 2.1 Protocol and registration Systematic reviews are well-established for examining effectiveness and are the highest- ranked form of evidence for addressing intervention questions [ 14 ]. The review was developed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement [ 15 ] and registered on the PROSPERO database in December 2021 (ref: CRD42022298879). 2.2 Search strategy The search strategy was developed in collaboration with an information specialist at Monash University (Supplementary File 1). To refine the search strategy, we mapped known relevant studies citing studies using a web-based application ( https://www.citationgecko.com/ ). We examined search yields from our test searches to ensure that they contained several studies from this ‘gold set.’ The Medline (OVID), Embase (OVID), Cochrane Central, CINAHL, PsycINFO and Business Source Complete, Institute for Work and Health (IWH) were then searched from inception to December 2021. 2.3 Inclusion and exclusion criteria Due to uncertainty about the volume of evidence in this area, our review was inclusive in defining ‘sleep health interventions’ and also defined mental health broadly as ‘ … a state of well-being in which an individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and is able to make a contribution to his or her community’ [ 16 ]. This definition is not limited to absence of diagnosed mental illness. Therefore, in addition to measures of depression, anxiety, stress and burnout, studies measuring mental health and mood outcomes were included in the review. This reflects the complex inter-relationships between shift work, sleep and mental health. Inclusion and exclusion criteria for the review are presented in Table 1. View this table: View inline View popup Download powerpoint Table 1: Inclusion and exclusion criteria for review 2.4 Study Selection Search results were exported into Covidence (Cochrane technology platform). Title/abstracts and full text studies were independently screened by two reviewers drawn from the research team (PB, PK, TM, AL, EG, TS). Conflicts were resolved by a third reviewer (PB or PK). 2.5 Data extraction Data extraction focused on the following data items: intervention type/subtype; study type; population (workplace industry where relevant); sample size; intervention/comparator; mental health outcomes; and direction of evidence. Eligible studies were dichotomised by intervention into those using a recognised mental health outcome (defined as those which referenced the mental health tool(s) used) and those which did not. The presence of a statistically significant finding pertaining to any sleep parameter was also recorded. 2.6 Involvement of experienced shift workers The review team included two experienced shift workers recruited through a sleep researcher (TS) using a position description (Supplementary File 2) - a registered nurse with 14 years’ experience including several years working night shifts in a major metropolitan hospital (MA); and a health and safety manager with 25 years’ experience of shift work in the mining and construction sector (DF). The experienced shift workers participated in development of the review protocol (MA); provided reflections on the interventions identified in the review; and described strategies they used for managing their sleep. 3. Results Study selection Searching identified 7,006 citations; 4,900 citations and abstracts were screened; 443 studies were assessed in full text; and 102 primary studies met the inclusion criteria (Supplementary File 3). Interventions identified were rostering (n=39); pharmacotherapies (n=25); lighting (n=13); cognitive behavioural therapy (CBT; n= 5); napping (n=5); and education/training (n=3). Eleven studies were either combinations of these or were single studies of an intervention. Healthcare workers were the most studied group (n=44). Fourteen studies were laboratory-based shift work simulations. Other participant groups included manufacturing workers (n=11); emergency workers (n=9); aviation workers (n=5); military personnel (n=3); and workers in extractive industries (n=3). Few studies focused only on workers identified as having insomnia (n=4) or shift work disorder (n=3). Tables 2 - 8 present key study characteristics and findings which are summarised below including experienced shift worker perspectives. Rostering interventions (N=39) Most studies (32/39) used a referenced measure of mental health. Interventions encompassed changes to shift duration; shift cycle/rotation direction (forwards vs. backwards rotation) and on-call arrangements (Table 2 ). A forward shift system refers to shifts that rotate to a later time through a working week (e.g., from a morning to evening to night shift). Study designs were mainly pre-post (n=18) and quasi-experimental (n=9) rather than randomised. View this table: View inline View popup Table 2: Summary of studies implementing rostering interventions (n=39) Populations were predominantly from healthcare (n=19); manufacturing (n=8); police / fire and social services (n=5) and extractive industries. In contrast to other interventions, almost half of the studies (n=17) had over 100 participants. Mental health outcomes were evenly spread with at least 5 studies examining burnout, wellbeing, stress and quality of life. Twelve studies reported positive effects including six with samples of over 100. All except one [ 17 ] used referenced mental health outcome measures. In 1583 manufacturing workers, positive impacts on work stress were reported in response to a change from backward to forward rotating rosters; reduction from three to two ‘fast rotating’ shifts; and three instead of two days off after night shifts [ 18 ]. Switching from a backward to a forward shift system was also associated with improvements in quality of life amongst 179 steel manufacturing workers [ 19 ]. Cull et al. (2006) examined the impact of new Graduate Medical Education resident duty hour limits, reporting improved resident self-reported well-being in a sample of 767 program directors and graduating residents. [ 17 ] Similarly, Miulli et al.’s 2010 study of 108 residents reported positive impacts; [ 20 ] Amendola et al. (2011) reported a significant effect of shift length on quality of work life in 231 police, with the highest quality of work life when working 10-hour shifts; [ 21 ] Knauth et al. (1998) reported improvements in quality of life amongst 179 steel manufacturing workers following a switch from a backward to a forward shift system; [ 19 ] and Harma et al. (2005) examined rapid forward-rotating shifts which avoided consecutive night shifts and optimised free time in 140 airline workers, reporting positive well-being outcomes. [ 22 ] Another nine studies reflected the above findings on the impact of duty hour limits; however, Schuh et al. (2011) [ 23 ] have reported a negative effect of the Institute of Medicine work hours restrictions on burnout in 34 medical residents. Twelve studies reported no effect of shift manipulations on mental health outcomes. Five studies reported negative outcomes; however these were not restricted to wellbeing. One study by Fitzgibbons et al. (2012) [ 24 ] reported from 216 survey responses that duty hour restrictions had led to a non-significant improvement in wellbeing but also a significant decrease in satisfaction with medical education. Increased work compression and fatigue resulting from duty hour restrictions in 27 residents was reported by Auger et al. (2012) [ 25 ], however, neither of these studies used a referenced mental health outcome. Another two studies reported negative effects including weight gain and fatigue following a change from 8-hour to 12-hour shifts in 205 cleanroom workers [ 26 ] and negative effects of long (over 13- hour) shifts on quality of life in 386 police officers [ 27 ]. Collectively, these findings indicate that shifting to a forward rotating shift schedule has a generally positive impact on mental health across multiple professions; work hour restrictions in resident-level doctors have positive mental health impacts but a perception of compromised professional education; and shorter (10-hour) shifts are optimal compared with longer (12+ hour) shifts. The existence of studies with generally higher sample sizes conducted across multiple disciplines indicates that comparatively more confidence can be placed in these findings compared to other intervention categories. Experienced shift worker reflections: rostering In mining and construction, the mistaken belief that people ‘adapt’ their circadian system to night shifts leads some workers to prefer many consecutive night shifts even though this adversely affects health, and increased pay for night shift may also drive this preference. Combined with the fact that some construction tasks cannot be done at night, this raises the question of whether night shifts in construction represent good return on investment. Conversely, there is no question of the need for shift work in nursing. Systems for rostering include online tools that enable nurses to indicate availability over a defined period. This assists managers in the considerable task of coordinating multiple staff and having some control over rostering may contribute to lower work-related stress in employees since higher occupational autonomy is associated with better wellbeing and workplace productivity. Ten- hour shifts appear more frequently in nursing compared to mining and construction, where 12-hour shifts can occur, especially in large construction projects. Across both these sectors (and potentially others), a lack of research-informed education may contribute to low employee awareness of the potential impacts of shift work on mental health and work-life balance. Pharmacological interventions (n=25) Most studies examining pharmacological interventions (23/25) used a referenced measure of mental health and employed a randomised controlled trial or crossover-RCT design (Table 3). The most frequently studied agents were melatonin and other hypnotics to target improvements in sleep; and stimulants (e.g., modafinil, armodafinil) to target sleepiness when awake. Only two studies recruited over 100 participants. Fourteen of the pharmacological studies reported positive effects on mood. View this table: View inline View popup Table 3: Summary of studies implementing pharmacological interventions (n = 26) Several studies of hypnotics reported positive results for mood and mental health symptoms [ 58 , 74 , 79 , 64 ]. Modafinil during shifts had significant positive effects on quality of life in an RCT of 278 participants [ 62 ]. It was also found to be a good alternative to amphetamine in a quasi-experimental study of 41 military personnel [ 72 ], and reversed disruptions in cognitive performance and mood during the night shift in a small, simulated shift work study [ 11 ]. Armodafinil had possible positive effects on quality of life after 6 weeks following an RCT in 383 participants [ 61 ]. Caffeine had positive effects on mood in a laboratory-based study of 30 participants [ 70 ]. Shimian granules (SMG, a herbal remedy) taken twice daily for a month improved anxiety and depression symptoms in 53 shift nurses [ 80 ]. Small studies (n under 20) reported positive effects of Marijuana [ 68 ], Methamphetamine [ 65 ], Temazepam [ 58 ] and Zolpidem [ 66 ]. These studies indicate that pharmacological agents can have positive effects on mental health in shift workers. Specifically, four studies reported that hypnotics positively impacted mood and mental health symptoms, and a further three studies, including the study with the largest sample size, reported positive effects of Modafinil. The remaining seven studies reporting positive impacts of pharmacological interventions all examined different agents, and therefore little confidence can be placed in these findings. Some adverse effects on mental health were reported for Zolpidem [ 66 ]; however, these were rare in the context of the overall body of evidence. Experienced shift worker reflections: pharmacological interventions In mining and construction, pharmacological use is quite common, especially stimulants such as caffeine. Sedative agents are less frequently used, however there is a misconception that alcohol aids sleep. Understanding of the specific role of melatonin is relatively poor in these sectors, with many believing that it is a ‘sleeping tablet’. Another factor worthy of consideration in construction, being male-dominated, is the stigma associated with help- seeking for mental illness which may reinforce self-medication. Unlike in construction, melatonin and sedative use (e.g. Stilnox and Temazepam) may be more frequent in nursing. Echoing the above, education on appropriate use of medications and the potential harms associated with misuse could reduce adverse consequences associated with ‘self-medication’ with both pharmacological agents and other substances such as alcohol and caffeine. Lighting interventions (N=14) Twelve of the 14 studies examining lighting interventions in shift work used a referenced measure of mental health (Table 4). Studies explored various combinations of duration of exposure and intensity of light to target alertness, mood and circadian phase shifting. Most studies employed an RCT crossover (n=5) or RCT (n=4) design, with the remainder pre-post (n=3) and quasi-experimental (n=2). Six studies recruited healthcare workers, including one with a focus on healthcare workers with insomnia. All sample sizes were under 100. The predominant mental health outcome examined in light studies was mood (n=10). Four studies reported positive findings for the effect of light on mood. Positive effects of lighting on wellbeing were also reported in two studies and anxiety and depression were reported to improve in one study. In most studies, however, mood was not the primary outcome of interest, with light primarily applied to influence sleep health through its influence on the timing or phase of the circadian rhythm, or acute alerting effects. View this table: View inline View popup Table 4: Summary of studies implementing rostering lighting interventions (n = 13) Experienced shift worker reflections: lighting In both mining and construction and nursing, most are unaware of the potential for light to aid sleep health and comparatively more attention is paid to other strategies (e.g., shift design). In some nursing settings there is a ‘night duty’ light switch in which environmental lighting is considerably dimmed. However, this is primarily directed towards promoting sleep for patients, whereas lighting design in this sector should also accommodate for brighter (rather than dim) lighting for workers given the links with light exposure and mental health. Healthcare is a somewhat unique sector in relation to lighting due to the need to accommodate two groups differently; workers and patients. Cognitive Behavioural Therapy (CBT) (N=5) All five studies used a referenced measure of mental health (Table 5). CBT approaches included tailored sessions for specific workforces; for example, Jang (2020) [ 94 ] examined therapy for insomnia and nightmares in firefighters. Study populations were mixed and included healthcare and aviation workers. All five studies found statistically significant effects; however, all had sample sizes under 80. Despite the generally positive results, the variation in the content of CBT, populations and small sample sizes, makes it difficult to draw firm conclusions on the effect of CBT on mental health outcomes in shift workers. View this table: View inline View popup Download powerpoint Table 5: Summary of studies implementing Cognitive Behavioural Therapy (CBT) (n= 5) Experienced shift worker reflections: CBT In mining and construction, CBT specific to the issue of sleep health is not frequently encountered, with mental health being a much greater focus (with passing references to rest, sleep and mindfulness). Similarly, the framing of CBT in nursing should emphasise its application to sleep health, which is the focus of most of the included studies. Although this type of CBT does have ‘flow-on’ benefits to mental health, it is primarily directed at sleep health behaviours. This means that participants do not need to identify as suffering from mental health challenges to participate. This subtle distinction is important as negative connotations can be associated with therapies for managing mental health. Napping interventions (N=5) All five napping studies used a referenced measure of mental health (Table 6). Four of the five studies were RCTs, with one crossover-RCT design. Two studies recruited healthcare workers; two were laboratory-based simulations and one study recruited air traffic controllers. Naps were between 10 and 120 minutes. Mental health outcomes measured were mood (n=3) and anxiety (n=2). Results of napping on mood were mixed; one study reported a negative effect of a 10-minute nap on mood compared with a longer 30-minute nap (n=31, laboratory-based) [ 98 ], one reported more vigour with a 40-minute nap compared with no- nap (n=49 healthcare workers) [ 101 ], and one study reported no effect on mood of either a 45-minute or 120-minute nap (n=51 aviation workers) [ 100 ]. Of the two studies measuring anxiety, one reported no effect of a 30-min nap (n=63 healthcare workers) [ 99 ] and the other found significant reversal of anxiety following a 120-minute nap (n=13, laboratory-based) [ 102 ]. Given the modest sample sizes and variation in participant groups and nap times, no firm conclusions on the effect of napping on mental health outcomes in shift workers can be made from the included studies. View this table: View inline View popup Download powerpoint Table 6: Summary of studies implementing napping interventions (n = 5) Experienced shift worker reflections: napping In nursing, napping for 2 hours prior to the first night shift, and/or napping prior to the end of night shifts can be helpful strategies. Conversely, napping is frowned upon in mining and construction as it is associated with laziness – in fact it can be a sackable offence. Additionally, although sleep is possible in nursing settings, it is comparatively hard to create an environment where napping could take place in the building sector, even if it was viewed as an acceptable strategy. Education and Training interventions (N=3) Only one of the three studies examining education and training [ 103 ] used a referenced measure of mental health (Table 7). Education across the studies encompassed the science of sleep, sleep disorders, and sleep strategies. All studies were pre-post in design with small samples (n=30-61). Although statistically significant findings were reported for a positive effect of education and training on quality of life, burnout and psychological distress, the evidence base is insufficient to draw firm conclusions. View this table: View inline View popup Download powerpoint Table 7: Summary of studies implementing education and training (n = 3) Experienced shift worker reflections: education and training There is a need to enhance educational interventions in both construction and nursing sectors. In construction, ‘toolbox’ talks can be engaging but still focus on mental health. To reinforce sleep health, in addition to harnessing talks (which are sometimes mandatory prior to commencing building projects), consideration should be given to strategies that support talks, such as posters and opportunities for conversations. Other opportunities to incorporate sleep health education into professional development in construction include ‘rain days’ where work is not possible. In nursing, like construction, there is an existing professional development infrastructure, however awareness of education on sleep is low. It is not incorporated into undergraduate training and although some industry bodies such as unions do produce sleep education it is not routinely incorporated into workplace-based professional development. This identifies an important opportunity for targeted education on sleep health in multiple shift working sectors. Other or Multifaceted Interventions (N=11) Eleven studies examined the effect of combinations of the above interventions or were single studies of an intervention (Table 8). Nine of these used a referenced measure of mental health. Six multifaceted studies examined: Education / training + rostering intervention (n=6 healthcare workers, no effect on mood) [ 115 ] Light + exercise (n=30 aviation workers, positive effect on mood) [ 106 ] Light + melatonin (n=17 mining workers, no effect on anxiety and depression) [ 107 ] Light + scheduled sleep (n=39, laboratory-based, no effect on mood) [ 112 ] Napping + light therapy glasses (n=95, positive effect on wellbeing) [ 113 ] Zolpidem + napping (n=18 aviation workers, positive effect on mood) [ 59 ] Collectively, these studies reported variable effects on mental health outcomes. Given the small sample sizes and variations in intervention combinations, no firm conclusions can be made regarding multifaceted interventions based on these studies. The remaining five studies examined Transcranial Direct Current Stimulation / Caffeine [ 109 ]; Yogic relaxation [ 110 ]; Asparagus extract [ 111 ]; Homeopathy [ 114 ] and Meridian acupuncture [ 108 ]. Little confidence can be placed in the findings of individual studies. View this table: View inline View popup Table 8: Summary of studies implementing other or multifaceted interventions (n = 11) Discussion This is the first known systematic review focusing on effectiveness of sleep health interventions on mental health in shift workers. Almost two thirds (n=64) of the 102 included studies evaluated either shift rostering (n=39) or pharmacological interventions (n=25) and over half (n=54) recruited healthcare (n=43) or manufacturing (n=11) workers. Pleasingly, 87 of the 102 included studies used a referenced mental health or mood measure permitting a higher degree of confidence in these studies. The insights from the two experienced shift workers with over 10 years of experience each illustrate the importance of understanding a broad array of workplace contexts given the variable acceptability and feasibility of interventions observed. It is acknowledged that this review did not gather in-depth information across many shift work sectors or examine implementation literature. Hence the insights are not necessarily generalisable to their industries and/or transferable to other sectors. More in-depth co-design with a representative panel of shift workers would be needed to deepen understanding of overarching themes and specific sectoral issues. Effective/positive interventions Rostering studies with large sample sizes demonstrated that a forward rotating shift schedule (i.e., day, afternoon then night shift) has a generally positive impact on mental health compared to the reverse rotation. Several studies in healthcare demonstrated that work hour restrictions in resident-level doctors have positive mental health impacts, and studies in other sectors report shorter shifts are optimal compared with longer shifts (i.e., 10-hours vs. 12+- hours). Hypnotic and stimulant medications have positive mental health effects. Four of the 14 lighting studies also reported positive effects on mood and a further three demonstrated improvements in wellbeing, anxiety and depression. Despite promising findings pertaining to cognitive behavioural therapy, education and training, napping and multifaceted interventions, there were insufficient studies in these categories to warrant firm conclusions. In many cases, mental health and mood indicators were not the primary focus of the studies. As this review focused on mental health outcomes, in-depth analysis of the full array of outcome measures in the included studies was not conducted. Future analysis of the balance between mental health and sleep outcomes, as well as exploration of the links between these at the level of individual studies, would shed light on this important interaction. The perspectives of two experienced shift workers enhanced understanding of areas in which there is little or no research, yet which are explored in real-world settings. Interventions used by these members of the research team (MA and DF) yet not explicitly represented in the 102 studies include alterations in dietary habits (including reducing alcohol consumption), use of air conditioning in hot climates, use of wearable technologies and ear plugs and white noise to distract from daytime interruptions to sleep. Conversely, the experienced shift worker researchers were less familiar with some interventions such as the use of goggles or sunglasses to avoid light at inappropriate times. Other insights and nuances from experienced shift workers also sharpen the focus on review findings. For example, there are clear opportunities to better promote the importance of sleep hygiene among shift workers. The need to better promote sleep health in nursing, for instance, was surprising given the amount of research that has been conducted in this sector. This implies that there is still much work to be done in translating research knowledge into policy and practice. Although some studies have examined the consequences of shift work on social activity, the role of family in supporting the demands of shift workers is under- researched. Another important but under-represented consideration pertains to commutes home from shift work. For example, on selected building projects, any employee with a commute duration of an hour or more is offered nearby accommodation for recovery prior to the commute. This is consistent with research indicating that driving for 45 minutes or more following a night shift may be unsafe [ 116 ]. There are important cultural differences between work sectors in relation to sleep health interventions. Where mining and construction workers have relatively high buy-in to structured education such as ‘toolbox’ talks, updates of in-service education can be low in nursing, with older nurses in particular benefitting more from informal ‘hallway’ conversations; napping is facilitated in nursing but frowned upon in construction; lighting is less practically applicable in construction compared to nursing. This underscores the importance of sector-specific approaches to research and practice. Shift work by its nature restricts access to healthcare services such as general practitioners. This means that they are less likely to be exposed to this cohort, and potentially less aware of circadian rhythm disturbances and the specific interventions that may address them. Limited access to healthcare services also reduces opportunities for shift work employees to identify and manage mental (and general) health issues as well as sleep disturbances. A possible strategy for addressing this is organisational rather than community-level provision of health support services, either in-person (for example onsite nurses and other professionals), or via other resources including online platforms. For who A major limitation in the literature is a lack of studies examining mental health outcomes in occupational groupings outside of healthcare, manufacturing, emergency services and mining. These include transport and logistics, call centre workers and cleaners. Even amongst the occupations studied, the health workforce was dominant. This is the only occupational cohort in this review where firm conclusions can be drawn regarding the effect of sleep interventions on mental health, in particular with regards to rostering and pharmacological interventions which were the most frequently studied in the review. In what context The included studies were predominantly undertaken in first-world settings, notably the United States and Europe. Studies of shift workers in Low and Middle-Income Countries (LMIC) were lacking. Workplace regulatory standards for workers in LMIC countries are potentially less rigorous; for example, the two biggest influences on work hour restrictions in doctors were the US Graduate Medical Education resident duty hour limits and the European Working Time Directive on junior doctors. Knowledge of similar regulations in LMIC is lacking, and no research examining duty hours was identified in this review. Strengths of this review are a comprehensive search strategy across multiple databases; independent screening of all citations / abstracts and full text studies by two researchers; and a broad definition of interventions to ensure that all primary studies measuring mental health outcomes were captured. There are some limitations to acknowledge in this version of the review. Although there were no year restrictions on the search, non-English studies were excluded. Whilst study design, sample size and use of a referenced mental health outcome measure were used to interpret the findings, no formal quality appraisal was undertaken owing to the large volume and heterogeneity of the studies. Recommendations The most critical recommendation for business leaders, policymakers and researchers is that mental health impacts and outcomes associated with shift work require greater recognition. Sleep health interventions for shift workers appropriately focus on influencing circadian timing, sleep length and sleep quality. Improvements in these parameters are also likely to positively influence mental health because of the known link between poor sleep, circadian rhythms, and mental illness. Relatedly, more consideration needs to be given to multifaceted interventions that combine strategies addressing both sleep and mental health. This is especially important given the large array of strategies reported by the experienced shift workers in the research team. Research into the effectiveness of such approaches is lacking; only six of the 102 included studies examined multifaceted interventions. There is presently little or no research addressing the majority of shift working populations around the world. More research examining mental health outcomes must be directed at occupational groups outside of health and in LMIC settings. Although the focus on healthcare shift workers has appropriately been driven by knowledge of burnout in the medical professions as well as the risk to patients, equal or even greater risks exist, for example in mining and transport and in poorly regulated occupational settings. Finally, despite a large number of studies being identified, most studies had small sample sizes. This reduces confidence in and transferability of findings, even when robust study designs are employed. Multi-centre studies spanning larger populations and even countries are therefore needed. This is feasible given the reproducibility of interventions such as setting shift schedules, using pharmaceuticals or applying light therapy. Better co-ordination and standardisation of such interventions would also address the heterogeneity within each intervention category, which further compromises applicability of identified studies. Conclusions A systematic review of sleep health interventions for managing mental health in shift workers identified 102 primary studies. Interventions predominantly examined shift rostering (n=39), pharmacological therapies (n=25) and used of light (n=14). Healthcare workers were the focus of almost half (n=43) of the included studies. Utilising forward-rotating shifts (day, afternoon, then night shift) and restricting work hours for junior doctors were shown to positively impact mental health and mood outcomes; however, a small number of studies also reported negative impacts of hour restrictions. Both sedative and stimulant medications were also shown to have positive mental health effects. There was evidence supporting the use of lighting interventions to enhance mental health, however sample sizes were small. Few conclusions could be drawn on other interventions. Based on the perspectives of two experienced shift workers, there is considerable variation in the acceptability and feasibility of interventions across different sectors. This is driven in part by sector-specific cultural norms and relatively low awareness of sleep hygiene and its relationship to mental health. Given these insights, the dearth of research addressing mental health outcomes outside of the health professions assumes even greater importance. There is also a lack of research beyond high-income countries. Many studies did not give the same weight to mental health and sleep outcomes, as reflected by lack of multifaceted intervention studies. With the majority of the global shift working population under-represented by existing research, this area warrants major focus by business leaders, policy makers and researchers. Data Availability All data produced in the present study are available upon reasonable request to the authors. Acknowledgements The author team thank Katrina Tepper from the Monash University Library for her expert assistance in developing the search strategy for this review; and Cong Lem for his assistance in data extraction. This project was funded by The Wellcome Trust. The authors have no conflicts to declare. Footnotes ↵ ^ Monika and David are members of the research team with lived experience of shift work who provided perspectives on review findings in the context of their shift work professions. They do not have an academic affiliation. References [1]. ↵ Torquati L , Mielke GI , Brown WJ , Burton NW , Kolbe-Alexander TL . Shift Work and Poor Mental Health: A Meta-Analysis of Longitudinal Studies . Am J Public Health 2019 ; 109 : e13 – 20 . doi: 10.2105/AJPH.2019.305278 . OpenUrl CrossRef [2]. Kantermann T , Juda M , Vetter C , Roenneberg T . Shift-work research: Where do we stand, where should we go? Sleep Biol Rhythms 2010 ; 8 : 95 – 105 . doi: 10.1111/j.1479-8425.2010.00432.x . OpenUrl CrossRef Web of Science [3]. ↵ Walker WH , Walton JC , DeVries AC , Nelson RJ . Circadian rhythm disruption and mental health . Transl Psychiatry 2020 ; 10 : 28 . doi: 10.1038/s41398-020-0694-0 . OpenUrl CrossRef PubMed [4]. ↵ Walker WH , Walton JC , DeVries AC , Nelson RJ . Circadian rhythm disruption and mental health . Transl Psychiatry 2020 ; 10 : 28 . doi: 10.1038/s41398-020-0694-0 . OpenUrl CrossRef PubMed [5]. ↵ Rajaratnam SMW , Howard ME , Grunstein RR . Sleep loss and circadian disruption in shift work: health burden and management . Med J Aust 2013 ; 199 : S11 – 5 . doi: 10.5694/mja13.10561 . OpenUrl CrossRef PubMed [6]. ↵ Culpepper L . The social and economic burden of shift-work disorder . J Fam Pract 2010 ; 59 : S3 – 11 . OpenUrl PubMed [7]. ↵ Leger D . The Cost of Sleep-Related Accidents: A Report for the National Commission on Sleep Disorders Research . Sleep 1994 ; 17 : 84 – 93 . doi: 10.1093/sleep/17.1.84 . OpenUrl CrossRef PubMed Web of Science [8]. ↵ Murray JM , Sletten TL , Magee M , Gordon C , Lovato N , Bartlett DJ , et al. Prevalence of Circadian Misalignment and Its Association With Depressive Symptoms in Delayed Sleep Phase Disorder . Sleep 2017 ; 40 . doi: 10.1093/sleep/zsw002 . OpenUrl CrossRef PubMed [9]. Emens J , Lewy A , Kinzie JM , Arntz D , Rough J . Circadian misalignment in major depressive disorder . Psychiatry Res 2009 ; 168 : 259 – 61 . doi: 10.1016/j.psychres.2009.04.009 . OpenUrl CrossRef PubMed Web of Science [10]. ↵ Baron KG , Reid KJ. Circadian misalignment and health . Int Rev Psychiatry 2014 ;26:139–54. doi: 10.3109/09540261.2014.911149 . OpenUrl CrossRef PubMed [11]. ↵ Hart CL , Haney M , Vosburg SK , Comer SD , Gunderson E , Foltin RW . Modafinil Attenuates Disruptions in Cognitive Performance During Simulated Night-Shift Work . Neuropsychopharmacology 2006 ; 31 : 1526 – 36 . doi: 10.1038/sj.npp.1300991 . OpenUrl CrossRef PubMed Web of Science [12]. ↵ Jarnefelt H , Lagerstedt R , Kajaste S , Sallinen M , Savolainen A , Hublin C . Cognitive behavioral therapy for shift workers with chronic insomnia . Sleep Med 2012 ; 13 : 1238 – 46 . doi: 10.1016/j.sleep.2012.10.003 . OpenUrl CrossRef PubMed [13]. ↵ Harrison EM , Schmied EA , Easterling AP , Yablonsky AM , Glickman GL . A Hybrid Effectiveness-Implementation Study of a Multi-Component Lighting Intervention for Hospital Shift Workers . Int J Environ Res Public Heal 2020 ; 17 : 7 . doi: 10.3390/ijerph17239141 . OpenUrl CrossRef [14]. ↵ Coleman K , Norris S , Middleton P , Tooher-Asernip-S R , Salisbury-Biotext J. NHMRC additional levels of evidence and grades for recommendations for developers of guidelines STAGE 2 CONSULTATION 2008:1–21. [15]. ↵ Page MJ , McKenzie JE , Bossuyt PM , Boutron I , Hoffmann TC , Mulrow CD , et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews . BMJ 2021 : n71 . doi: 10.1136/bmj.n71 . OpenUrl CrossRef PubMed [16]. ↵ World Health Organization. Mental health: strengthening our response 2022 . https://www.who.int/news-room/fact-sheets/detail/mental-health-strengthening-our-response (accessed April 1, 2022). [17]. ↵ Cull WL , Mulvey HJ , Jewett EA , Zalneraitis EL , Allen CE , Pan RJ . Pediatric Residency Duty Hours Before and After Limitations . Pediatrics 2006 ; 118 : e1805 – 11 . doi: 10.1542/peds.2006-0210 . OpenUrl CrossRef PubMed Web of Science [18]. ↵ Klein Hesselink J , de Leede J , Goudswaard A . Effects of the new fast forward rotating five-shift roster at a Dutch steel company . Ergonomics 2010 ; 53 : 727 – 38 . doi: 10.1080/00140139.2010.489651 . OpenUrl CrossRef PubMed [19]. ↵ Knauth P , Hornberger S . Changes from weekly backward to quicker forward rotating shift systems in the steel industry . Int J Ind Ergon 1998 ; 21 : 267 – 73 . doi: 10.1016/S0169-8141%2897%2900049-8 . OpenUrl CrossRef [20]. ↵ Miulli DE , Valcore JC . Methods and implications of limiting resident duty hours . J Am Osteopath Assoc 2010 ; 110 : 385 – 95 . OpenUrl PubMed [21]. ↵ Amendola KL , Weisburd D , Hamilton EE , Jones G , Slipka M . An experimental study of compressed work schedules in policing: Advantages and disadvantages of various shift lengths . J Exp Criminol 2011 ; 7 : 407 – 42 . doi: 10.1007/s11292-011-9135-7 . OpenUrl CrossRef Web of Science [22]. ↵ Harma M , Tarja H , Irja K , Mikael S , Jussi V , Anne B , et al. A controlled intervention study on the effects of a very rapidly forward rotating shift system on sleep- wakefulness and well-being among young and elderly shift workers . Int J Psychophysiol 2006 ; 59 : 70 – 9 . doi: 10.1016/j.ijpsycho.2005.08.005 . OpenUrl CrossRef PubMed Web of Science [23]. ↵ Schuh LA , Khan MA , Harle H , Southerland AM , Hicks WJ , Falchook A , et al. Pilot trial of IOM duty hour recommendations in neurology residency programs: Unintended consequences: Correction . Neurology 2011 ; 77 . doi: 10.1212/WNL.0b013e318233c6c3 . OpenUrl CrossRef [24]. ↵ Fitzgibbons SC , Chen J , Jagsi R , Weinstein D . Long-term follow-up on the educational impact of ACGME duty hour limits: a pre-post survey study . Ann Surg 2012 ; 256 : 1108 – 12 . OpenUrl CrossRef PubMed [25]. ↵ Auger KA , Landrigan CP , Gonzalez del Rey JA, Sieplinga KR, Sucharew HJ, Simmons JM. Better rested, but more stressed? Evidence of the effects of resident work hour restrictions . Acad Pediatr 2012 ; 12 : 335 – 43 . doi: 10.1016/j.acap.2012.02.006 . OpenUrl CrossRef PubMed [26]. ↵ Yamada Y , Kameda M , Noborisaka Y , Suzuki H , Honda M , Yamada S . Excessive fatigue and weight gain among cleanroom workers after changing from an 8-hour to a 12-hour shift . Scand J Work Environ Heal 2001 ; 27 : 318 – 26 . doi: 10.5271/sjweh.620 . OpenUrl CrossRef [27]. ↵ Bell LB , Virden TB , Lewis DJ , Cassidy BA . Effects of 13-Hour 20-Minute Work Shifts on Law Enforcement Officers’ Sleep, Cognitive Abilities, Health , Quality of Life, and Work Performance. Police Q 2015 ; 18 : 293 – 337 . doi: 10.1177/1098611115584910 . OpenUrl CrossRef [28]. Antiel RM , Reed DA , Van Arendonk KJ , Wightman SC , Hall DE , Porterfield JR , et al. Effects of Duty Hour Restrictions on Core Competencies, Education, Quality of Life, and Burnout Among General Surgery Interns . JAMA Surg 2013 ; 148 : 448 . doi: 10.1001/jamasurg.2013.1368 . OpenUrl CrossRef PubMed [29]. Bilimoria KY , Chung JW , Hedges L V , Dahlke AR , Love R , Cohen ME , et al. National Cluster-Randomized Trial of Duty-Hour Flexibility in Surgical Training . N Engl J Med 2016 ; 374 : 713 – 27 . OpenUrl CrossRef PubMed [30]. Brainch N , Schule P , Laurel F , Bodic M , Jacob T . Psychiatric Emergency Services - Can Duty-Hour Changes Help Residents and Patients? Psychiatr Q 2018 ; 89 : 771 – 8 . doi: 10.1007/s11126-018-9579-2 . OpenUrl CrossRef PubMed [31]. Caputo , L. M. ; Hawkes , A. P. ; Gosche , E. E. ; Vellman , P. W. ; Lange , N. R. ; Salottolo , K. M. ; Coniglio , R. ; Mains CW . The impact of changing work schedules on American firefighters’ sleep patterns and well-being . Signa Vitae 2015 ; 10 : 25 . doi: 10.22514/SV101.042015.3 . OpenUrl CrossRef [32]. Chang YS , Wu YH , Hsu CY , Tang SH , Yang LL , Su SF . Impairment of perceptual and motor abilities at the end of a night shift is greater in nurses working fast rotating shifts . Sleep Med 2011 ; 12 : 866 – 9 . doi: 10.1016/j.sleep.2011.03.018 . OpenUrl CrossRef PubMed [33]. Chang YS , Wu YH , Chen HL , Hsu CY . Is one day off sufficient for re-adaptation to a daytime routine after two consecutive nights of work? Ergonomics 2018 ; 61 : 162 – 8 . doi: 10.1080/00140139.2017.1330492 . OpenUrl CrossRef PubMed [34]. Hakola T , Niemela P , Ronnberg S , Ropponen A. Longer Work Shifts, Faster Forward Rotation-More Sleep and More Alert in Aircraft Inspection . Int J Environ Res Public Heal [Electronic Resour 2021 ; 18 : 30 . doi: 10.3390/ijerph18158105 . OpenUrl CrossRef [35]. Hanoa R , Baste V , Kooij A , Sommervold L , Moen BE . No difference in self reported health among coalminers in two different shift schedules at Spitsbergen, Norway, a two years follow-up . Ind Health 2011 ; 49 : 652 – 7 . OpenUrl PubMed [36]. Kandolin I , Huida O . Individual flexibility: an essential prerequisite in arranging shift schedules for midwives . J Nurs Manag 1996 ; 4 : 213 – 7 . doi: 10.1046/j.1365-2834.1996.02174.x . OpenUrl CrossRef PubMed [37]. Karlson B , Eek F , Ørbæk P , Österberg K . Effects on sleep-related problems and self- reported health after a change of shift schedule . J Occup Health Psychol 2009 ; 14 : 97 – 109 . doi: 10.1037/a0014116 . OpenUrl CrossRef PubMed Web of Science [38]. Hornberger S , Knauth P . Follow-up intervention study on effects of a change in shift schedule on shiftworkers in the chemical industry . Int J Ind Ergon 1998 ; 21 : 249 – 57 . doi: 10.1016/S0169-8141(97)00051-6 . OpenUrl CrossRef [39]. Landrigan CP , Fahrenkopf AM , Lewin D , Sharek PJ , Barger LK , Eisner M , et al. Effects of the Accreditation Council for Graduate Medical Education Duty Hour Limits on Sleep, Work Hours, and Safety . Pediatrics 2008 ; 122 : 250 – 8 . doi: 10.1542/peds.2007-2306 . OpenUrl CrossRef PubMed Web of Science [40]. Loudoun R . Balancing shiftwork and life outside work: Do 12-h shifts make a difference? Appl Ergon 2008 ; 39 : 572 – 9 . doi: 10.1016/j.apergo.2007.12.004 . OpenUrl CrossRef PubMed [41]. Low J , Tan M , See K , Aw M . Sleep, activity and fatigue reported by Postgraduate Year 1 residents: a prospective cohort study comparing the effects of night float versus the traditional overnight on-call system . Singapore Med J 2018 ; 59 : 652 – 5 . doi: 10.11622/smedj.2018036 . OpenUrl CrossRef PubMed [42]. Lowden A , Kecklund G , Axelsson J , Åkerstedt T . Change from an 8-hour shift to a 12- hour shift, attitudes, sleep, sleepiness and performance . Scand J Work Environ Heal 1998 ; 24 : 69 – 75 . OpenUrl [43]. Mitchell RJ , Williamson AM . Evaluation of an 8 hour versus a 12 hour shift roster on employees at a power station . Appl Ergon 2000 ; 31 : 83 – 93 . doi: 10.1016/s0003-6870(99)00025-3 . OpenUrl CrossRef PubMed Web of Science [44]. Monk TH , Buysse DJ , Billy BD . Using daily 30-min phase advances to achieve a 6- hour advance: circadian rhythm, sleep, and alertness . Aviat Space Environ Med 2006 ; 77 : 677 – 86 . OpenUrl PubMed [45]. Monk TH , Buysse DJ , Billy BD , DeGrazia JM . Using nine 2-h delays to achieve a 6-h advance disrupts sleep, alertness, and circadian rhythm . Aviat Space Environ Med 2004 ; 75 : 1049 – 57 . OpenUrl PubMed [46]. Paley MJ , Price JM , Tepas DI . The impact of a change in rotating shift schedules: A comparison of the effects of 8, 10 and 14 h work shifts . Int J Ind Ergon 1998 ;21:293–305. doi: 10.1016/S0169-8141%2897%2900048-6 . OpenUrl CrossRef [47]. Parshuram CS , Amaral ACKB , Ferguson ND , Baker GR , Etchells EE , Flintoft V , et al. Patient safety, resident well-being and continuity of care with different resident duty schedules in the intensive care unit: A randomized trial . Can Med Assoc J 2015 ; 187 : 321 – 9 . doi: 10.1503/cmaj.140752 . OpenUrl Abstract / FREE Full Text [48]. Parthasarathy S , Hettiger K , Budhiraja R , Sullivan B . Sleep and Well-Being of ICU Housestaff . Chest 2007 ; 131 : 1685 – 93 . doi: 10.1378/chest.06-1398 . OpenUrl CrossRef PubMed Web of Science [49]. Pierce JL , Dunham RB . The 12-hour work day: A 48 hour, eight-day week . Acad Manag J 1992 ; 35 : 1086 – 98 . doi: 10.2307/256542 . OpenUrl Abstract / FREE Full Text [50]. Ripp JA , Bellini L , Fallar R , Bazari H , Katz JT , Korenstein D . The impact of duty hours restrictions on job burnout in internal medicine residents: A three-institution comparison study . Acad Med 2015 ; 90 : 494 – 9 . doi: 10.1097/ACM.0000000000000641 . OpenUrl CrossRef [51]. Shochat T , Hadish-Shogan S , Banin Yosipof M , Recanati A , Tzischinsky O. Burnout , Sleep, and Sleepiness during Day and Night Shifts in Transition from 8- to 12-Hour Shift Rosters among Airline Ground Crew Managers . Clocks & Sleep 2019 ; 1 : 226 – 39 . doi: 10.3390/clockssleep1020020 . OpenUrl CrossRef PubMed [52]. Sussman D , Paul JE . The impact of transitioning from a 24-hour to a 16-hour call model amongst a cohort of Canadian anesthesia residents at McMaster University - a survey study . Adv Med Educ Pract 2015 ;6:501–6. [53]. Vetter C , Fischer D , Matera JL , Roenneberg T . Aligning work and circadian time in shift workers improves sleep and reduces circadian disruption . Curr Biol 2015 ; 25 : 907 – 11 . doi: 10.1016/j.cub.2015.01.064 . OpenUrl CrossRef PubMed [54]. Yamada Y , Kameda M , Noborisaka Y , Suzuki H , Honda M , Yamada S . Excessive fatigue and weight gain among cleanroom workers after changing from an 8-hour to a 12-hour shift . Scand J Work Environ Health 2001 ; 27 : 318 – 25 . OpenUrl PubMed Web of Science [55]. De Valck E , Quanten S , Berckmans D , Cluydts R . Simulator driving performance, subjective sleepiness and salivary cortisol in a fast-forward versus a slow-backward rotating shift system . Scand J Work Environ Health 2007 ; 33 : 51 – 7 . doi: 10.5271/sjweh.1064 . OpenUrl CrossRef PubMed [56]. Duplessis CA , Miller JC , Crepeau LJ , Osborn CM , Dyche J . Submarine watch schedules: underway evaluation of rotating (contemporary) and compressed (alternative) schedules . Undersea Hyperb Med 2007 ; 34 : 21 – 33 . OpenUrl PubMed [57]. Kamine TH , Barron RJ , Lesicka A , Galbraith JD , Millham FH , Larson J . Effects of the new Accreditation Council for Graduate Medical Education work hour rules on surgical interns: a prospective study in a community teaching hospital . Am J Surg 2013 ; 205 : 163 – 8 . doi: 10.1016/j.amjsurg.2012.10.006 . OpenUrl CrossRef PubMed [58]. ↵ Caldwell JL , Prazinko BF , Rowe T , Norman D , Hall KK , Caldwell JA . Improving daytime sleep with temazepam as a countermeasure for shift lag . Aviat Sp Environ Med 2003 ; 74 : 153 – 63 . OpenUrl [59]. ↵ Caldwell Jr JA , Caldwell JL . Comparison of the effects of zolpidem-induced prophylactic naps to placebo naps and forced rest periods in prolonged work schedules . Sleep 1998 ; 21 : 79 – 90 . doi: 10.1093/sleep/21.1.79 . OpenUrl CrossRef PubMed [60]. Cavallo A , Ris D , Succop P , Jaskiewicz J . Melatonin treatment of pediatric residents for adoption to night shift work . Ambul Pediatr 2005 ; 5 : 172 – 7 . doi: 10.1367/A04-124R.1 . OpenUrl CrossRef PubMed [61]. ↵ Erman Mk YRSDJ . The effect of armodafinil on patient-reported functioning and quality of life in patients with excessive sleepiness associated with shift work disorder: a randomized, double-blind, placebo-controlled trial . Prim Care Companion J Clin Psychiatry 2012 ; 14 . doi: 10.4088%2FPCC.12m01345 . OpenUrl CrossRef [62]. ↵ Erman MK , Rosenberg R , The USMSWSDSG . Modafinil for excessive sleepiness associated with chronic shift work sleep disorder: effects on patient functioning and health-related quality of life . Prim Care Companion J Clin Psychiatry 2007 ; 9 : 188 – 94 . OpenUrl CrossRef PubMed [63]. Farahmand S , Vafaeian M , Vahidi E , Abdollahi A , Bagheri-Hariri S , Dehpour AR . Comparison of exogenous melatonin versus placebo on sleep efficiency in emergency medicine residents working night shifts: A randomized trial . World J Emerg Med 2018 ; 9 : 282 – 7 . doi: 10.5847/wjem.j.1920-8642.2018.04.008 . OpenUrl CrossRef PubMed [64]. ↵ Folkard S , Arendt J , Clark M . Can melatonin improve shift workers’ tolerance of the night shift? Some preliminary findings . Chronobiol Int 1993 ; 10 : 315 – 20 . OpenUrl CrossRef PubMed Web of Science [65]. ↵ Hart CL , Ward AS , Haney M , Nasser J , Foltin RW . Methamphetamine attenuates disruptions in performance and mood during simulated night-shift work . Psychopharmacology (Berl ) 2003 ; 169 : 42 – 51 . doi: 10.1007/s00213-003-1464-4 . OpenUrl CrossRef PubMed [66]. ↵ Hart CL , Ward AS , Haney M , Foltin RW . Zolpidem-Related Effects on Performance and Mood During Simulated Night-Shift Work . Exp Clin Psychopharmacol 2003 ; 11 : 259 – 68 . doi: 10.1037/1064-1297.11.4.259 . OpenUrl CrossRef PubMed [67]. Jockovich M , Cosentino D , Cosentino L , Wears RL , Seaberg DC . Effect of exogenous melatonin on mood and sleep efficiency in emergency medicine residents working night shifts . Acad Emerg Med 2000 ; 7 : 955 – 8 . OpenUrl PubMed Web of Science [68]. ↵ Keith DR , Gunderson EW , Haney M , Foltin RW , Hart CL . Smoked marijuana attenuates performance and mood disruptions during simulated night shift work . Drug Alcohol Depend 2017 ; 178 : 534 – 43 . doi: 10.1016/j.drugalcdep.2017.04.036 . OpenUrl CrossRef PubMed [69]. Monchesky TC , Billings BJ , Phillips R , Bourgouin J . Zopiclone in insomniac shiftworkers . Evaluation of its hypnotic properties and its effects on mood and work performance. Int Arch Occup Environ Heal 1989 ; 61 : 255 – 9 . OpenUrl [70]. ↵ McHill AW , Smith BJ , Wright KP . Effects of Caffeine on Skin and Core Temperatures, Alertness, and Recovery Sleep During Circadian Misalignment . J Biol Rhythms 2014 ; 29 : 131 – 43 . doi: 10.1177/0748730414523078 . OpenUrl CrossRef PubMed Web of Science [71]. Neri DF , Wiegmann D , Stanny RR , Shappell SA , McCardie A , McKay DL . The effects of tyrosine on cognitive performance during extended wakefulness . Aviat Space Environ Med 1995 ; 66 : 313 – 9 . OpenUrl PubMed Web of Science [72]. ↵ Pigeau R , Naitoh P , Buguet A , McCann C , Baranski J , Taylor M , et al. Modafinil, d- amphetamine and placebo during 64 hours of sustained mental work. I. Effects on mood, fatigue, cognitive performance and body temperature . J Sleep Res 1995 ;4:212– 28. [73]. Punja S SLOKVS . Rhodiola rosea for mental and physical fatigue in nursing students: a randomized controlled trial . PLoS One 2014 ; 9 . [74]. ↵ Scollo-Lavizzari G . Hypnotic efficacy and clinical safety of midazolam in shift- workers . Br J Clin Pharmacol 1983 ; 16 Suppl 1 : 73S – 78S . OpenUrl PubMed [75]. Walsh JK , Sugerman JL , Muehlbach MJ , Schweitzer PK . Physiological Sleep Tendency on a Simulated Night Shift: Adaptation and Effects of Triazolam . Sleep 1988 ; 11 : 251 – 64 . doi: 10.1093/sleep/11.3.251 . OpenUrl CrossRef PubMed [76]. Wesnes , K. ; Luthringer , R. ; Ambrosetti , L. ; Edgar , C. ; Petrini O . The effects of a combination of Panax ginseng, vitamins and minerals on mental performance, mood and physical fatigue in nurses working night shifts: a double-blind, placebo controlled trial . Curr Top Nutraceutical Res 2003 ; 1 : 169 – 74 . OpenUrl [77]. West NP , Hughes L , Ramsey R , Zhang P , Martoni CJ , Leyer GJ , et al. Probiotics, Anticipation Stress, and the Acute Immune Response to Night Shift . Front Immunol 2021 ; 11 : 1 – 10 . doi: 10.3389/fimmu.2020.599547 . OpenUrl CrossRef [78]. Wright SW , Lawrence LM , Wrenn KD , Haynes ML , Welch LW , Schlack HM . Randomized clinical trial of melatonin after night-shift work: efficacy and neuropsychologic effects . Ann Emerg Med 1998 ; 32 : 334 – 40 . OpenUrl CrossRef PubMed Web of Science [79]. ↵ Zeitzer Jm JDSMAQYLHBHJE . Effect of Suvorexant vs Placebo on Total Daytime Sleep Hours in Shift Workers: a Randomized Clinical Trial . JAMA Netw Open n.d .; 3 : e206614 . [80]. ↵ Zhang L , Zhang R , Shen Y , Qiao S , Hui Z , Chen J . Shimian granules improve sleep, mood and performance of shift nurses in association changes in melatonin and cytokine biomarkers: A randomized, double-blind, placebo-controlled pilot study . Chronobiol Int 2020 ; 37 : 592 – 605 . doi: 10.1080/07420528.2020.1730880 . OpenUrl CrossRef PubMed [81]. James M , Tremea MO , Jones JS , Krohmer JR , James M , Tremea MO , et al. Can melatonin improve adaptation to night shift? Am J Emerg Med 1998 ; 16 : 367 – 70 . OpenUrl CrossRef PubMed Web of Science [82]. Wesensten NJ , Reichardt RM , Balkin TJ. Ampakine (CX717) effects on performance and alertness during simulated night shift work . Aviat Sp Environ Med 2007 ;78:937– 43. [83]. Costa G , Gaffuri E , Ghirlanda G , Minors DS , Waterhouse JM . Psychophysical conditions and hormonal secretion in nurses on a rapidly rotating shift schedule and exposed to bright light during night work . Work Stress 1995 ; 9 : 148 – 57 . doi: 10.1080/02678379508256549 . OpenUrl CrossRef [84]. Costa G , Kovacic M , Bertoldi A , Minors D , Waterhouse J . The use of a light visor during night work by nurses . Biol Rhythm Res 1997 ; 28 : 16 – 25 . doi: 10.1076/brhm.28.1.16.12984 . OpenUrl CrossRef [85]. Eastman CI . High-intensity light for circadian adaptation to a 12-h shift of the sleep schedule . Am J Physiol Regul Integr Comp Physiol 1992 ; 263 : R428 – 36 . doi: 10.1152/ajpregu.1992.263.2.r428 . OpenUrl CrossRef PubMed [86]. Stewart KT , Hayes BC , Eastman CI . Light treatment for NASA shiftworkers . Chronobiol Int 1995 ; 12 : 141 – 51 . OpenUrl PubMed Web of Science [87]. Eastman CI , Stewart KT , Mahoney MP , Liu L , Fogg LF . Dark goggles and bright light improve circadian rhythm adaptation to night-shift work . Sleep 1994 ; 17 : 535 – 43 . OpenUrl PubMed Web of Science [88]. Canazei M , Pohl W , Bliem HR , Weiss EM . Acute effects of different light spectra on simulated night-shift work without circadian alignment . Chronobiol Int 2017 ; 34 : 303 – 17 . doi: 10.1080/07420528.2016.1222414 . OpenUrl CrossRef PubMed [89]. Comtet H , Geoffroy PA , Kobayashi Frisk M , Hubbard J , Robin-Choteau L , Calvel L , et al. Light therapy with boxes or glasses to counteract effects of acute sleep deprivation . Sci Rep 2019 ; 9 : 18073 . doi: 10.1038/s41598-019-54311-x . OpenUrl CrossRef PubMed [90]. Huang LB , Tsai MC , Chen CY , Hsu SC . The effectiveness of light/dark exposure to treat insomnia in female nurses undertaking shift work during the evening/night shift . J Clin Sleep Med 2013 ; 9 : 641 – 6 . doi: 10.5664/jcsm.2824 . OpenUrl CrossRef PubMed [91]. Rahman SA , Shapiro CM , Wang F , Ainlay H , Kazmi S , Brown TJ , et al. Effects of filtering visual short wavelengths during nocturnal shiftwork on sleep and performance . Chronobiol Int 2013 ; 30 : 951 – 62 . doi: 10.3109/07420528.2013.789894 . OpenUrl CrossRef PubMed [92]. Sletten TL , Raman B , Magee M , Ferguson SA , Kennaway DJ , Grunstein RR , et al. A Blue-Enriched, Increased Intensity Light Intervention to Improve Alertness and Performance in Rotating Night Shift Workers in an Operational Setting . Nat Sci Sleep 2021 ; 13 : 647 – 57 . OpenUrl CrossRef PubMed [93]. Figueiro MG , Rea MS , Boyce P , White R , Kolberg K . The effects of bright light on day and night shift nurses’ performance and well-being in the NICU . Neonatal Intensive Care 2001 ; 14 : 29 – 32 . OpenUrl [94]. ↵ Jang EH , Hong Y , Kim Y , Lee S , Ahn Y , Jeong KS , et al. The Development of a Sleep Intervention for Firefighters: The FIT-IN (Firefighter’s Therapy for Insomnia and Nightmares) Study . Int J Environ Res Public Heal [Electronic Resour 2020 ; 17 : 24 . doi: 10.3390/ijerph17238738 . OpenUrl CrossRef [95]. Jarnefelt H HMSMPTVJMKPHC. Cognitive behavioural therapy interventions for insomnia among shift workers: RCT in an occupational health setting . Sleep Sci 2020 ; 12 . doi: 10.1007/s00420-019-01504-6 . OpenUrl CrossRef [96]. Lee KA , Gay CL , Alsten CR . Home-based behavioral sleep training for shift workers: a pilot study . Behav Sleep Med 2014 ; 12 : 455 – 68 . doi: 10.1080/15402002.2013.825840 . OpenUrl CrossRef PubMed [97]. Peter L , Reindl R , Zauter S , Hillemacher T , Richter K . Effectiveness of an Online CBT-I Intervention and a Face-to-Face Treatment for Shift Work Sleep Disorder: A Comparison of Sleep Diary Data . Int J Environ Res Public Heal [Electronic Resour 2019 ; 16 : 24 . doi: 10.3390/ijerph16173081 . OpenUrl CrossRef [98]. ↵ Centofanti SA , Hilditch CJ , Dorrian J , Banks S . The impact of short night-time naps on performance, sleepiness and mood during a simulated night shift . Chronobiol Int 2016 ; 33 : 706 – 15 . doi: 10.3109/07420528.2016.1167722 . OpenUrl CrossRef PubMed [99]. ↵ Chang Y-S , Wu Y-H , Lu MR , Hsu C-Y , Liu C-K , Hsu C . Did a brief nap break have positive benefits on information processing among nurses working on the first 8-h night shift? Appl Ergon 2015 ; 48 : 104 – 8 . doi: 10.1016/j.apergo.2014.11.005 . OpenUrl CrossRef PubMed [100]. ↵ Della Rocco PS , Comperatore C , Caldwell L , Cruz C. The effects of napping on night shift performance. FAA Off Aviat Med Reports 2000. [101]. ↵ Smith-Coggins R , Howard SK , Mac DT , Wang C , Kwan S , Rosekind MR , et al. Improving alertness and performance in emergency department physicians and nurses: the use of planned naps . Ann Emerg Med 2006 ; 48 : 596 – 604 . OpenUrl CrossRef PubMed Web of Science [102]. ↵ Takeyama H , Itani T , Tachi N , Sakamura O , Suzumura H . Psycho-physiological effects of naps during night shifts on morning types and evening types . J Occup Health 2002 ; 44 : 89 – 98 . doi: 10.1539/joh.44.89 . OpenUrl CrossRef Web of Science [103]. ↵ James L , Samuels CH , Vincent F . Evaluating the Effectiveness of Fatigue Management Training to Improve Police Sleep Health and Wellness: A Pilot Study . J Occup Environ Med 2018 ; 60 : 77 – 82 . OpenUrl PubMed [104]. Holzinger B , Mayer L , Levec K , Munzinger MM , Klosch G . Sleep coaching: Non- pharmacological treatment of non-restorative sleep in Austrian railway shift workers . Arh Hig Rada Toksikol 2019 ; 70 : 186 – 93 . doi: 10.2478/aiht-2019-70-3244 . OpenUrl CrossRef PubMed [105]. Holzinger B , Levec K , Munzinger MM , Mayer L , Klosch G . Managing daytime sleepiness with the help of sleepcoaching, a non-pharmacological treatment of non- restorative sleep . Sleep Breath 2020 ; 24 : 253 – 8 . OpenUrl PubMed [106]. ↵ Barger LK , Sullivan JP , Lockley SW , Czeisler CA . Exposure to Short Wavelength- Enriched White Light and Exercise Improves Alertness and Performance in Operational NASA Flight Controllers Working Overnight Shifts . J Occup Environ Med 2021 ; 63 : 111 – 8 . doi: 10.1097/JOM.0000000000002054 . OpenUrl CrossRef PubMed [107]. ↵ Bjorvatn B , Stangenes K , Oyane N , Forberg K , Lowden A , Holsten F , et al. Randomized placebo-controlled field study of the effects of bright light and melatonin in adaptation to night work . Scand J Work Environ Health 2007 ; 33 : 204 – 14 . OpenUrl PubMed Web of Science [108]. ↵ Cho Y , Joo JM , Kim S , Sok S . Effects of Meridian Acupressure on Stress, Fatigue , Anxiety, and Self-Efficacy of Shiftwork Nurses in South Korea. Int J Environ Res Public Heal [Electronic Resour 2021 ; 18 : 15 . doi: 10.3390/ijerph18084199 . OpenUrl CrossRef [109]. ↵ McIntire LK , McKinley RA , Goodyear C , Nelson J . A Comparison of the Effects of Transcranial Direct Current Stimulation and Caffeine on Vigilance and Cognitive Performance During Extended Wakefulness . Brain Stimul 2014 ; 7 : 499 – 507 . doi: 10.1016/j.brs.2014.04.008 . OpenUrl CrossRef PubMed [110]. ↵ Raghul S , Vasanthan S , Bhavanani AB , Jaiganesh K , Madanmohan T . Effects of overnight sleep deprivation on autonomic function and perceived stress in young health professionals and their reversal through yogic relaxation (Shavasana) . Natl J Physiol Pharm Pharmacol 2018 ; 8 : 1256 – 61 . doi: 10.5455/njppp.2018.8.0415003052018 . OpenUrl CrossRef [111]. ↵ Sakai S , Nagata M , Nagata T , Mori K . Improved Sleep Quality and Work Performance Among Shift Workers Consuming a Foods with Function Claims Containing Asparagus Extract . J UOEH 2021 ; 43 : 15 – 23 . doi: 10.7888/juoeh.43.15 . OpenUrl CrossRef PubMed [112]. ↵ Smith MR , Fogg LF , Eastman CI . A compromise circadian phase position for permanent night work improves mood, fatigue, and performance . Sleep J Sleep Sleep Disord Res 2009 ; 32 : 1481 – 9 . doi: 10.1093/sleep/32.11.1481 . OpenUrl CrossRef [113]. ↵ van Woerkom M . A quasi-experimental study into the effects of naps and therapy glasses on fatigue and well-being . J Nurs Manag 2021 ; 29 : 562 – 5 . OpenUrl PubMed [114]. ↵ La Pine MP , Malcomson FN , Torrance JM , Marsh N V. Night shift: can a homeopathic remedy alleviate shift lag? DCCN - Dimens Crit Care Nurs 2006;25:130– 6. [115]. ↵ Smith-Coggins R , Rosekind MR , Buccino KR , Dinges DF , Moser RP . Rotating shiftwork schedules: can we enhance physician adaptation to night shifts? Acad Emerg Med 1997 ; 4 : 951 – 61 . OpenUrl CrossRef PubMed Web of Science [116]. ↵ Lee ML , Howard ME , Horrey WJ , Liang Y , Anderson C , Shreeve MS , et al. High risk of near-crash driving events following night-shift work . Proc Natl Acad Sci 2016 ; 113 : 176 – 81 . doi: 10.1073/pnas.1510383112 . OpenUrl Abstract / FREE Full Text View the discussion thread. Back to top Previous Next Posted July 29, 2025. Download PDF Supplementary Material Data/Code Email Thank you for your interest in spreading the word about medRxiv. NOTE: Your email address is requested solely to identify you as the sender of this article. Your Email * Your Name * Send To * Enter multiple addresses on separate lines or separate them with commas. You are going to email the following Sleep health interventions for managing mental health in shift workers: A systematic review Message Subject (Your Name) has forwarded a page to you from medRxiv Message Body (Your Name) thought you would like to see this page from the medRxiv website. Your Personal Message CAPTCHA This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Share Sleep health interventions for managing mental health in shift workers: A systematic review Peter Bragge , Jane Burns , Paul Kellner , Monika Allan , David Fitzgerald , Emily Grundy , Alyse Lennox , Talar R. Moukhtarian , Shantha M.W. Rajaratnam , Tracey L. Sletten medRxiv 2025.07.28.25331984; doi: https://doi.org/10.1101/2025.07.28.25331984 Share This Article: Copy Citation Tools Sleep health interventions for managing mental health in shift workers: A systematic review Peter Bragge , Jane Burns , Paul Kellner , Monika Allan , David Fitzgerald , Emily Grundy , Alyse Lennox , Talar R. Moukhtarian , Shantha M.W. Rajaratnam , Tracey L. Sletten medRxiv 2025.07.28.25331984; doi: https://doi.org/10.1101/2025.07.28.25331984 Citation Manager Formats BibTeX Bookends EasyBib EndNote (tagged) EndNote 8 (xml) Medlars Mendeley Papers RefWorks Tagged Ref Manager RIS Zotero Tweet Widget Facebook Like Google Plus One Subject Area Occupational and Environmental Health Subject Areas All Articles Addiction Medicine (568) Allergy and Immunology (863) Anesthesia (300) Cardiovascular Medicine (4435) Dentistry and Oral Medicine (444) Dermatology (382) Emergency Medicine (608) Endocrinology (including Diabetes Mellitus and Metabolic Disease) (1509) Epidemiology (15228) Forensic Medicine (30) Gastroenterology (1124) Genetic and Genomic Medicine (6598) Geriatric Medicine (668) Health Economics (997) Health Informatics (4536) Health Policy (1368) Health Systems and Quality Improvement (1613) Hematology (540) HIV/AIDS (1264) Infectious Diseases (except HIV/AIDS) (15916) Intensive Care and Critical Care Medicine (1103) Medical Education (623) Medical Ethics (146) Nephrology (667) Neurology (6599) Nursing (346) Nutrition (998) Obstetrics and Gynecology (1144) Occupational and Environmental Health (957) Oncology (3332) Ophthalmology (974) Orthopedics (369) Otolaryngology (420) Pain Medicine (436) Palliative Medicine (130) Pathology (663) Pediatrics (1693) Pharmacology and Therapeutics (691) Primary Care Research (711) Psychiatry and Clinical Psychology (5447) Public and Global Health (9231) Radiology and Imaging (2198) Rehabilitation Medicine and Physical Therapy (1370) Respiratory Medicine (1196) Rheumatology (593) Sexual and Reproductive Health (712) Sports Medicine (530) Surgery (712) Toxicology (99) Transplantation (289) Urology (265) (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'a005a1955b72593a',t:'MTc3OTU1NTc3Ng=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();