This is an excerpt from Action Plan for Allergies by William Briner & American College of Sports Medicine.
While you can never predict with absolute certainty when you are going to have an allergy flare-up or an asthma attack, you usually realize what triggers your exacerbations. Certain outdoor allergens, such as pollen or grasses; and indoor allergens, such as dust or cats, can provoke an allergy flare-up. Exercise, cold weather, and viral respiratory infections can trigger an asthma attack in many people. Knowing your triggers may help you avoid potentially serious situations. Following are some guidelines to help you anticipate and head off exercise-related allergy and asthma problems before they occur.
Most individuals with allergic rhinitis find that certain seasons or environmental surroundings trigger their allergy symptoms. Knowing, for example, that every autumn triggers a hay fever flare-up, you may choose to either avoid exercising outdoors or premedicate with an antihistamine when summer ends. If you have a significant allergy to dust mites and your gym is quite dusty, you again might premedicate before your workout or, in the worst case scenario, change to a cleaner gym. If you have a pollen allergy and the pollen count is high on your outdoor run day, devise a backup plan for indoor exercise that day. Learn to anticipate the potential difficulties your allergies might cause and devise a plan to overcome them and keep your workout schedule on track.
Similar to allergic rhinitis, environmental factors, such as dust or pollen, may exacerbate asthma symptoms or trigger an actual asthma attack. As previously discussed, another common trigger for asthma flare-ups is exercise. If you are a person with a known history of exercise-induced asthma, make a plan in advance to prevent symptoms or decrease them once they occur. The most common method of exercise-induced asthma (EIA) prevention is to know your triggers and use your bronchodilator, such as albuterol, before starting your exercise routine that day. Always carry your inhaler and (if needed) delivery device (spacer) with you, either on your person or in your nearby gym bag. If you begin to have shortness of breath or chest tightness, you do not want to be caught without your rescue medication. Knowing your triggers is important if you have antigen-induced asthma. As with allergic rhinitis, if you are going to work out in a facility that has a lot of dust, and dust mites trigger your asthma symptoms, you should either premedicate or choose a different workout location. If you are going to train outside and you have asthma triggered by pollen or hay fever allergens, check the daily pollen counts with the local weather service. Have an alternate workout plan for those days when your planned training regimen might increase your chance of having an asthma attack. Remember that asthma and allergies should not prevent you from exercising, but you should have a prepared plan of action to prevent and treat flare-ups so that they don't interfere with your workouts.