I used to go to Work every day by walking around 2 Km, without doubt it helps a lot to arrive work clear minded and in good mood. I think is even better when you walk in group and you talk to the others.
I used to run part of the way to school because I was notoriously late. At the end of the year I aced the gym class mile run, but overall my unreliability caused much concern in other topics. I maintained for a time that exercise is vital for a healthy mind, but because I didn't exercise on purpose, I couldn't take advantage of it.