Canadian researchers made a brief review of active commuting and obesity. Active transportation is more frequent in some European countries with dedicated cycle and pedestrian paths, but in most developed societies, active transportation has declined in recent years. A weekly gross energy expenditure of at least 4 MJ is recommended to reduce all-cause and cardiovascular mortality. This can be achieved by walking 1.9 km in 22 minutes twice per day, 5 days per week, or by cycling at 16 km/h for 11 minutes twice per day, 5 days per week. More information is needed on active commuting, and the impact of such commuting on overall attitudes towards PA. It is also necessary to find better methods of involving the sedentary population, through both counselling and changes in urban design.