I consider myself a pretty active guy. I do more at 49 than I did at 29 from a physical standpoint. I walk, I run, I ride a bicycle, I go to the gym, I exercise at home, I go to kickboxing classes… Over the past 2 months or so, I have found that I am petering during my runs by the time I hit a mile. I have been blowing off kickboxing because I simply feel tired. Even my …