The best way to prevent an allergic reaction during exercise is to identify the allergen responsible for symptoms, and to avoid exposure to that allergen as much as possible. This may mean choosing a sport or activity that does not involve exposure to the allergen.

For example, someone allergic to ragweed may consider swimming at an indoor pool instead of jogging near a wooded or grassy area. Sometimes, a person may be able to continue an activity by simply shifting the environment. For example, individuals with pollen or insect allergies can reduce their risk for allergy symptoms during exercise by running or playing tennis indoors, while those with dust allergies would benefit from heading outdoors.

Generally, activities that involve continuous activity, such as running, can cause more reactions than stop-and-go activities. The time of day and the weather can also play a factor. For instance, pollen counts are usually lowest during wet, chilly periods and in the evening hours. They tend to be highest in the mornings, and on warm, dry, windy days.

Of course, switching an activity or environment is not always possible or desirable. Those who are at risk for an allergic reaction during exercise should take the following precautions:

• Always warm up and cool down for at least 15 to 30 minutes before you begin strenuous activity.
  
  
• Pay close attention to symptoms. Slow down or stop exercising when appropriate.
  
  
• Choose appropriate activities. Fewer symptoms are likely in sports requiring short bursts of energy (e.g., basketball, tennis, swimming) than those that demand long periods of constant exercise (e.g., long-distance running, soccer).
  
  
• Do not exercise during respiratory illness (e.g., respiratory tract infection). The nasal and sinus passages filter out pollutants, irritants and allergens from the air, as well as warm and humidify the air before it is inhaled. Therefore, patients with illnesses that cause nasal and sinus congestion should avoid exercising until their symptoms subside.  
  
  
• Limit exercise when severe allergy symptoms are present. Allergy symptoms may be aggravated by increased activity.
  
  
• Watch the weather. Try to exercise when pollen counts are low. Cold, dry conditions can irritate bronchial tubes, so try to exercise indoors at such times.
  
  
• Cover the mouth with a scarf during cold weather. This warms the air entering the airways.
  
  
• Avoid pollution. Try not to exercise where traffic levels are high, or when smog or other air pollution is a factor.
  
  
• Keep away from open windows and doors while exercising indoors. This can help people with allergies reduce their contact with pollen and other outdoor allergens.
  
  
• Exercise on a mat. Patients with allergies should avoid exercising directly on carpeting, which can contain indoor allergens such as dust, dust mites and animal dander. Placing a mat over an area of the carpeting may help prevent allergy symptoms while exercising indoors.  
  
  
• Understand the dangers specific to your allergy. For instance, those with serious insect allergies should avoid wearing bright-colored clothing or strong perfumes that may attract insects. Also, avoid exercising near flower beds, bodies of water or other areas likely to attract insects.
  
  
• Be prepared. Those with known anaphylactic reactions triggered by exercise or other factors (e.g., insect stings) should carry an epinephrine shot in case of a life-threatening reaction. In addition, any work-out partners or instructors should be made aware of the allergy and be informed of what to do if a reaction occurs.
  
  
• Wear a medical alert bracelet with a list of allergies and medications required in case of a medical emergency.
  
  
• Always follow a physician’s advice. For instance, some patients may be instructed to use an inhaler 15 minutes before exercise to reduce the risk of reactions.