Why 10000 Steps?

Q:    Hey, Mr. Pedometer, why is it that you (and others) encourage us to walk 10,000 steps per day?  Is this just an arbitrarily chosen number, or is it based on some kind of research?

Why Walk in The Heat of Summer?

Q: Mr. Pedometer, I know you probably have addressed this before, but could you please remind me why – given the hot weather of summer – I should get out and walk more?