You probably already know that exercise is good for your heart, muscles, bones, and overall health. You’ve probably heard that exercise can help with stress, sleep, and maintaining a healthy weight too. But your gut? That may not be the first thing that comes to mind when you lace up your walking shoes. Most of us don’t head out for a walk thinking, “I should really do something nice for my digestive system today.” Usually, we’re thinking something more along the lines of, “I ate way too much for lunch,” or “I have been sitting at this desk for six…