Izzie is now 21 weeks old and VERY energetic. I know that she shouldn't have more than 5 minutes of exercise for each month of life per day, and I do stick to this. Now that she is 5 months she can do 25 minutes so I thought that I would take her for a half-decent run this morning ~ oh, what a mistake!! Firstly, she was all over the place, running back and forth in front of me; secondly she just kept wanting to stop and sniff (how inconsiderate); and thridly, she simply out-ran me!! The indignity of it ~ being out-run by a puppy!!