Increasing rates of sedentary living, often complemented by obesity, among large segments of the adult population are associated with costs to individual health and well-being and thereby to society as a whole. Although some workplaces offer physical activity opportunities, those employees who tend to need it the most (i.e., the health needy) are often not attracted. In this project, the investigators propose to develop and evaluate a programme that is targeted to the sedentary health needy employees. The investigators will work with the corporate partner (a large university) to attract such employees through an extensive social marketing driven campaign. A 16-week lunchtime walking programme is proposed in which walking groups are offered followed by support and motivational strategies for longer term independent walking. The investigators will examine the effects of the programme on total amount of walking (including a follow-up assessment 4 months later) and will use innovative technology (Smartphones) to also examine the effect of lunchtime walks on well-being and work performance within and between participants.

Inclusion Criteria:

• healthy, mobile, 18-65 year old employees who report they are engaging in less than 30 minutes of moderate intensity physical activity per week

Exclusion Criteria:

• employees with significant auditory or visual problems and those who have severe musculoskeletal disorders that prevent them from engaging in physical activity. Medical clearance will be requested for those who report any cardiovascular disease.