Harvard psychiatrist Dr. John Ratey paid a visit to the Saratoga campus on Nov. 19, appearing as part of the Common Ground Speaker series. The Common Ground Speaker Series was started by a group of Bay Area schools to feature experts in a variety of fields for the benefit of parents in various communities.

Ratey’s research into how exercise affects the brain has provided persuasive insight into how exercise can combat attention deficit hyperactivity disorder (ADHD), substance abuse and mood swings. He published his findings in his most recent book, “SPARK: The Revolutionary New Science of Exercise and the Brain.”

In the opening of his presentation, Ratey said he was “very passionate” about this topic, and that he aims to propel the discussion into the public’s awareness, hoping to “reverse where we’re going in many ways.” He began by using a photo of a close companion to illustrate his point.

“I brought along my friend here,” said Ratey, motioning to the large photo of a young Jack Russell terrier. “One of the things we found about exercise is that when you’re exercising, oftentimes you’ll have this flash of insight and creativity.”

When the dog first arrived, Ratey recalled going for a three-mile run, and wondering what to call the dog. “I came back and I had this brilliant idea of calling him Jack,” he said, earning some laughter from the crowd. The name stuck.

Ratey told of how early in his career in the Boston area, he worked with former marathon runners who had become injured and were forced to stop running, thereafter becoming depressed. After helping his patients work through their depression, many came back complaining that they had symptoms of ADHD. This was due in part to their reduced activity and exercise.

Intrigued, Ratey began looking more closely into the relationship between exercise and the brain. While explaining how the human brain evolved, he noted that the brain assisted in learning how to navigate and adapt to different environments in addition to evolving speech and other cognitive abilities. “Our moving brain is really our thinking brain,” he summarized.

One of the more sobering pieces of information Ratey displayed showed that children who were extremely obese scored nearly 30 points lower on I.Q. tests than children who were of normal weight. Another study found that obese adults in their late 70s had eight percent less brain volume than people of similar age who did not have weight problems. “Their brains looked like they were 95 years old,” Ratey said.

Some good news is that even people well into their lives can stave off such effects through basic exercise routines. “If you start exercising, even in middle age…if you begin and do it three to four times a week for forty minutes or so, brisk walking, you can push back the onset of cognitive decline later on by 10 to 15 years,” he said. Some studies show it may also have the benefit of cutting the danger of acquiring Alzheimer’s disease in half.

Later, Ratey showed that the prefrontal cortex, the area of the brain that plays a major role in the “executive functions” such as planning, organizing, evaluating consequences and learning from mistakes, “gets switched on by exercise.” Studies done with mice showed that exercise could even promote the growth of new brain cells.

Jack reappeared for a portion of the talk related to the importance of play. “One of the important ways of thinking about exercise is that it grows out of our need to play,” Ratey said. Playing, in the manner of children and young animals, for example, is an integral factor in the development and continued growth of the brain. “Every species that we’ve looked at plays, especially the young,” he said, citing the research of psychiatrist and clinical researcher Stuart Brown. “When you stop them from playing, their brains are smaller, they’re not as intelligent, they have a harder time integrating in groups, they tend to be more aggressive and don’t pick up the social cues if you take play away from them.”

To illustrate the point, Ratey used the example of the school system in Naperville, Ill., which began a rigorous physical education program that emphasized overall fitness and required students to exercise 45 minutes per day. Students in the school district went on to score first in science and sixth in math in an international test that compares the aptitudes of various countries.

Following the talk, Ratey took time to answer questions from the audience.