I'm noticing a pattern here, first two posts about caffeine, and now slowing down heart rate. Do you think you have a fast pulse?
Mine is about 66, I am hoping it will go down with consistant training.\
You might want to pick up Sally Edwards' book on heart rate training and heart rate training for cyclists. Slower pulse is obviously a sign of conditioning since your heart has to work less hard. Can't possibly change overnight unless you are on some prescribed drugs or something I guess.
FXjohn