Currently 4.1 million Canadians are employed in shiftwork. Shiftwork, defined as the organization of working time to cover more than the usual 8-hour workday and up to a 24-hour period, is prevalent in health care, emergency services, manufacturing, retail and hospitality. Given the growing demand for goods and services at all hours in today's society, the number of shift workers is unlikely to decrease. There is emerging evidence that shiftwork has many negative health implications, including a higher risk of cancer and other chronic diseases. A recent systematic review by members of the investigators study team reported preliminary evidence that changes in shift scheduling, timed exposure to bright light during a night shift, and pharmacological therapy for sleep, help to improve sleep and markers of circadian rhythm dysfunction in shift workers. However changes in shift schedules, and exposure to bright light may be difficult to implement in certain workplaces (i.e., specific hospital environments, police patrol cars) and long-term effects of pharmacological therapy are unknown. To date there is very limited research on effective health promotion strategies in this occupational group, who face unique challenges to engaging in health behaviour change. There is an urgent need to develop and evaluate interventions to improve health and reduce cancer risk in this high-risk population. Participation in regular physical activity is known to decrease risk of cancer and other chronic diseases, and may be a simple and cost-effective intervention that could be implemented in workplaces and by individual workers to mitigate this increased risk. Shift workers have unique barriers to participating in physical activity; therefore the feasibility of implementing such interventions must first be investigated.