The improvements in this case came in executive control, which consists of inhibition (resisting distraction, maintaining focus), working memory, and cognitive flexibility (switching between tasks). The images above show the brain activity in the group of kids who did the program as opposed to the group that didn't. It's the kind of difference that's so dramatic it's a little unsettling. The study only lasted nine months, but when you're only seven years old, nine months is a long time to be sitting in class with a blue head.

Earlier this month, another study found that a 12-week exercise program improved math and reading test scores in all kids, but especially in those with signs of ADHD. (Executive functioning is impaired in ADHD, and tied to performance in math and reading.) Lead researcher Alan Smith, chair of the department of kinesiology at Michigan State, went out on no limb at all in a press statement at the time, saying, "Early studies suggest that physical activity can have a positive effect on children who suffer from ADHD."

Last year a very similar study in the Journal of Attention Disorders found that just 26 minutes of daily physical activity for eight weeks significantly allayed ADHD symptoms in grade-school kids. The modest conclusion of the study was that "physical activity shows promise for addressing ADHD symptoms in young children." The researchers went on to write that this finding should be "carefully explored with further studies."

"If physical activity is established as an effective intervention for ADHD," they continued, "it will also be important to address possible complementary effects of physical activity and existing treatment strategies ..." Which is a kind of phenomenal degree of reservation compared to the haste with which millions of kids have been introduced to amphetamines and other stimulants to address said ADHD. The number of prescriptions increased from 34.8 to 48.4 million between 2007 and 2011 alone. The pharmaceutical market around the disorder has grown to several billion dollars in recent years while school exercise initiatives have enjoyed no such spoils of entrepreneurialism. But, you know, once there is more research, it may potentially be advisable to consider possibly implementing more exercise opportunities for kids.

Over all, the pandemic of physical inactivity, as Hillman and colleagues put it in their Pediatrics journal article today, is "a serious threat to global health" responsible for around 10 percent of premature deaths from noncommincable diseases. But it clearly manifests in ways more subtle than deaths, including scholastic performance, which we're continuously learning. I talked last week with Paul Nystedt, an associate professor of economics and finance at Jönköping University in Sweden, who just published a multi-country study that found that obese teenagers go on to earn 18 percent less money as adults than their peers, even if they are no longer obese. He believes that's most likely because of the adversity that obese kids experience from classmates and teachers, which leads to both cognitive and noncognitive disparities between obese and non-obese kids. Because obese children are more likely to come from low-income homes to begin with, that only perpetuates wealth gaps and stifles mobility. Nystedt and his coauthors conclude, "The rapid increase in childhood and adolescent obesity could have long-lasting effects on the economic growth and productivity of nations."