I usually write about an item in this week's news or in the recent medical literature.  Forgive me from straying from that path this week to share some personal reflections. For sedentary patients there is an enormous psychological barrier to exercise.  All primary care doctors face that barrier daily.  We encourage, cajole, practically shove our patients to become more physically active.  The vast majority of the time, despite the patient's and the doctor's best intentions, no change occurs.  ...