Physical inactivity is an important and largely avoidable cause of incapacity. Regular physical activity protects against several chronic diseases, including cardiovascular disease—one of the major causes of death in Hong Kong. Significant benefits can be achieved by regular participation in moderate amounts of either recreational or general lifestyle physical activities. Even more is gained from increasing the frequency, duration, and vigour of exercise. In Hong Kong, 59% of all adults lead a fairly sedentary lifestyle and only one in three exercise at levels that are thought to offer significant health benefits. An even more disturbing fact is that Hong Kong probably has the most inactive primary level schoolchildren in the world. The prevalence of these risk behaviours should make schoolchildren a priority for any public health prevention programme.