LAUSR

INTRODUCTION Shift work (an occupation requiring work between 2200 and 0500H) comprises approximately 20% of the workforce in Europe and North America [1]. This is likely to increase, with many shift workers (SWs) in emergency services, retail, hospitality, healthcare, transportation and manufacturing [2]. SWs are at increased risk for negative health outcomes, including cancer and other chronic diseases [3, 4]. Biological changes from poor lifestyle habits related to shift work (e.g. low physical activity (PA), poor nutrition, obesity) are thought to contribute to this risk; these factors are also amenable to lifestyle intervention [5]. PA in particular, reduces cancer risk [6], and has many positive physical and psychological benefits [7]. It is a simple, cost-effective strategy that may be implemented by individual workers or within workplaces to mitigate risk. Unfortunately, SWs are unlikely to engage in regular PA [8]. In Canada, only 15.9% of SWsmeet the PA guidelines and have lower levels of aerobic fitness than those of day workers [9]. Few behavioural interventions improving health outcomes in SWs have been published [10]. In a targeted PA intervention, nurses randomised to 4 months of supervised PA improved aerobic fitness, muscular strength, fatigue and musculoskeletal symptoms. However, authors reported low adherence and large loss to follow-up, perhaps due to the supervised scheduled sessions [11, 12]. Sustained behaviour change is a challenge and requires targeted efforts to encourage individuals to reach an adequate dose of PA to change health outcomes [13]. Due to irregular schedules and time constraints, SWs may be less likely to adhere to a traditional supervised PA intervention with face-to-face behavioural support [12]. Women SWs cite work schedule interference and lack of time as PA barriers and report scheduling flexibility as the most important in PA [14]. This highlights the need for a creative and innovative programming to promote PA in SWs. Distance-based interventions, in which individuals exercise independent of study staff or participants, may include telephone counselling and website or smart phone app-based technology. These interventions are highly flexible and may help overcome barriers related to timing and scheduling that are important for SWs. In a review of telephone-based PA interventions, 14 of 17 found evidence for behaviour change [15]. These may be a way to implement scalable, individuallytailored interventions in SWs. The primary objective of this study was to test the feasibility of a distance-based PA intervention in women SWs. Feasibility studies are important for establishing effective processes and understanding resources required before attempting a randomised controlled trial (RCT), in order to put forward interventions that are most likely to be efficacious [16]. As this work was funded by a grant to examine the role of lifestyle in reducing breast cancer risk in SWs, only women were included. A secondary objective was to conduct a preliminary evaluation of intervention efficacy, to estimate effect size for future studies.