Obesity rates in children have more than tripled since the 1970s, putting young people at an increased, earlier risk for health problems like heart disease. Investigators looking to reduce these risks led a study where, for 8 months, a group of 8 to 11 year olds with excess weight either exercised for about 40 minutes after school or played sedentary craft or board games. There were some health benefits to the exercisers, like a higher good cholesterol level. But other factors, like the stiffness of their big arteries … a key, early indicator of cardiovascular health … did not improve. Investigators say it may take exercise, coupled with a healthy diet, to reduce arterial stiffness …. But prevention is always the best strategy.