As a runner I’ve always known this. John J. Ratey’s fantastic new book, Spark, sets out to prove it. He shows how muscle movement produces proteins that play a role in our highest thought process. Certain case studies that prove that exercise can change our mental state and take us from a sluggish brain to a creative thinker. We runners could provide all the data he needs. Contrary to what couch sitters believe, post run we feel invigorated and fresh. Spark points out that exercise is a key combatant against depression, the leading cause of disability of the U.S.   For those of you who need more reasons to run or affirmation of why we do, I suggest picking up Spark.