Obviously in order to get the most from a blessing we should be awake and realize what the blessing is. But what about such cases as this man's young son who was fast asleep when I helped his father give him a blessing? There are good opinions that say if one Jew is sleeping in the minyan he can still be counted in. Also, we are told that a Jew who goes to the study hall and learns while there receives a blessing for going and a blessing for learning, while a Jew who only goes but does not learn still receives a blessing for going.
All this shows that mitzvahs that are fulfilled even with less than adequate attention still count. Then how much more so do they count when we do have the proper intention, when we realize what the mitzvah does to us and to the world around us when we do them properly!
Mitzvahs are a gift from Heaven, a way to please our Creator.