When my 15 month old runs around too much she breathes heavily and sounds like she is wheezing. Should I be concerned?

Maybe. Maybe not. A 15 month toddler who breathes with noise after running around may be wheezing. The easiest way to tell is to make an appointment with a pediatrician who is not too busy. After seeing the doctor, the toddler can go run around for a few minutes and come back to show the doctor what the breathing noises are like. If the child already had some wheezing in the past, he is more likely to wheeze again.
15 months wheezing. Yes you should have her checked.She may have asthma.