Thanks, MadisonGrrl,

From what you wrote, it is probably because I am de-trained (I am housebroken, though).

I am 48 and waaay out of shape. Resting hr is about 70., rode about a mile, I don't know what my max hr was. I can't do two things at once; check hr and ride a bike, chew gum and walk without hitting anything, etc.