My 5.5 month old is has started to have bouts of fast breathing for a minute or so at a time. I hear him wheeze also, not all the time, but it seems to be getting more frequent. I'm going to call the pedi tomorrow morning, but I'm very concerned now. I've heard him do this while he's nursing, playing, but not while he's sleeping. Could this be asthma, RSV or what??? Could it be just from getting excited about everything - my dh thinks he's just getting excited, but do babies wheeze when they're excited? He'll wheeze only once and then maybe again in 5 minutes or more...not continuously.