Hopeful

Today it was a L. Sansone Walk dvd and I did a 4 mile walk.  When I started I thought it would only be a two mile walk.  When I got done with two, I thought, ok, three,  I'll do three.  When I got done with three, I thought, ok, four, I'll do four.  When I got done with four, I thought, ok, I better finish and stop because I have people coming over to my house in 15 minutes for a Bible Study and you are dripping with sweat!  Is this an early indication that I am becoming addicted to exercise? or am I just being hopeful?