What does it mean to be physically healthy? Let’s say you have a BMI (body-mass index) of 22 (where the range between 20 and 25 is considered to be healthy) and you exercise at a moderate aerobic level for 45 minutes most days of the week, but you smoke a pack a day. Are you healthy? What if you have no chronic diseases and you exercise 30 minutes every day, alternating between aerobic exercise and weights, but you have a BMI of 29, which is overweight and almost obese. Are you healthy? You can see that the question of being in good health has a lot of grey areas. Does being healthy simply mean an absence of disease? More and more, the answer is no. The World Health Organization has been advocating a model of positive health for some time now, and it appears that governments, public health units and school boards are now listening and creating new models—some of which are outlined in Spark. Imagine a world where doctors would prescribe exercise before trying new medications. Today’s average 75-yr-old has three chronic diseases—most of which are preventable through lifestyle and exercise. In a world where our population is aging rapidly, this is bad news for our health systems. What would it be like to have a new school system where, (like in Naperville Central High school, near Chicago), physical activity is part of every day, not just regulated to gym class. What would that mean for our public health? Regular exercise has been empirically shown to have beneficial effects on people suffering from anxiety, depression, attention deficit disorder, chronic stress and various addictions. And active school children learn better, taking in more information in shorter periods of time. Spark should be mandatory reading for everyone.