There is increasing evidence to demonstrate that excessive and unhealthy patterns of sedentary behaviour can increase the risk of a range of health problems,independent to levels of physical activity. Increasingly, people are employed in low activity occupations with office workers being identified as one of the most sedentary roles. Small scale studies using prompts to remind office workers to stand have shown promising results, as well as representing a low-cost solution for employers. This study builds upon a recent pilot study investigating the impact of prompts delivered via Microsoft Outlook, on the sedentary behaviour of office workers.