Your Exercise Technique
Jumping headfirst into strenuous exercise without properly warming up could prompt exercise-induced bronchoconstriction (EIB), a condition characterized by a tight chest and trouble breathing, generally seen in people with asthma, but sometimes in people without respiratory problems. Try warmup and cooldown techniques, and to curb EIB, breathe through your nose rather than your mouth when you exercise. If you're sick with a cold and have asthma, stay put. Viruses can trigger an asthma attack.