Most adults in developed countries are too inactive, accumulating on average far less than the recommended 30 minutes of moderate-intensity physical activity on at least 5 days every week.1,2 Insufficient walking and low levels of other physical activities are key risk factors for developing chronic diseases such as obesity and type 2 diabetes,3 and lack of exercise and obesity are significantly associated with reduced life expectancy at 40 years of age.4 Physical inactivity can account for 6% to 10% of all deaths from noncommunicable diseases.5