Talk to your doctor about using a quick-relief inhaler like Proventil®, Ventolin®, or Maxair®, 15 minutes prior to strenuous activities. If this is not enough, adding Singulair® once a day for prevention can help. Also, taking a daily low-drowsy antihistamine like Zyrtec®, Clarinex®, or Allegra® during the seasons your allergies are worse might prevent allergy problems and consequently decrease asthma symptoms. 

If you do not have a specific diagnosis, an allergy evaluation or tests can pinpoint your specific problem and provide you with a plan that should enable you to play sports or participate in PE.