As Hormones Rise, Exercise Dies

Among the MANY rude changes that puberty brought for me was a loss of the desire to run around outside all day. Rather than beg to stay up past my bedtime, I began to embrace sleep. And that, according to a new study, is completely normal. Scientists surveyed about 1,000 children and found that nine-year-olds spent three hours running around on average. By the time kids hit 15, their physical activity had dipped closer to 30 minutes. Big change for just six years! Researchers speculated that schools had much to do with the shift, saying that children lose recess as they get older and sports teams become more exclusive. And here I thought it had to do with too much brooding.