How do you tell the difference between asthma and being out of shape?

Pulmonary functions: Pulmonary function testing while symptomatic can usually be used to confirm the presence of asthma.

It's not always easy: Either being out of shape or asthma can make you feel short of breath when you exercise. An allergist or pulmonologist can have you do a lung function test before and after exercise to see if you are having exercise-induced bronchospasm. Your doctor can give you an asthma inhaler, and you can take it before or after exercise. If it helps, you probably have some asthma.