II. Pathophysiology

  1. Hyperventilation of dry, cool air
  2. Loss of heat or water from lungs during Exercise

III. Epidemiology

  1. Occurs in 90% of Asthmatics
  2. May occur in as many as 29% of athletes
    1. Cold Weather athletes appear more susceptible
    2. Occurs in 50% of olympic cross country skiers

IV. Symptoms

  1. Timing
    1. Onset during or after Exercise
    2. Does not usually affect first 5 minutes of Exercise
    3. Symptom duration of 5 minutes or longer
  2. Exercise-related symptoms
    1. Shortness of Breath
    2. Wheezing
    3. Decreased Exercise endurance
    4. Chest tightness
    5. Cough
    6. Epigastric Pain
    7. Pharyngitis

V. Signs

  1. Cardiopulmonary exam normal at rest
  2. Exclude associated conditions (see differential diagnosis below)

VII. Diagnostics

  1. Obtain FEV1 or Peak Flow at rest (exclude Asthma)
  2. Exercise Challenge with Pulmonary Function Testing
    1. Not required for classic presentation
    2. Most patients may be treated empirically

VIII. Management: General Measures

  1. Maintain regular Exercise for physical conditioning
  2. Warm up and cool down for 10 minutes before and after
  3. Exercise in humidified, warm environment
  4. Cover nose and mouth during Cold WeatherExercise
    1. Consider heat exchange mask (available at sporting good stores)
  5. Avoid Exercise within 2 hours following a meal
  6. Avoid Exercise in high allergen, ozone or pollution

IX. Management: Medications

  1. Treat related conditions
    1. Asthma
    2. Allergic Rhinitis
  2. Primary Agents
    1. Short-acting Beta Agonist (Albuterol, Pirbuterol)
      1. Use 2 puffs, 15-30 minutes before Exercise
  3. Secondary Adjunctive Agents
    1. Step 1: Leukotriene Modifiers (preferred if comorbid Allergic Rhinitis)
      1. Taken on regular schedule
      2. Montelukast (Singulair)
        1. Montelukast is associated with increased risk of Major Depression and Suicide
        2. https://www.fda.gov/news-events/press-announcements/fda-requires-stronger-warning-about-risk-neuropsychiatric-events-associated-asthma-and-allergy
      3. Zafirlukast (Accolate)
      4. Zileuton XR (Zyflo CR)
        1. Other Leukotriene Modifiers are preferred due to adverse effects including hepatotoxicity
    2. Step 2: Mast Cell Stabilizer 15 minutes before Exercise
      1. Mast Cell Stabilizers are low efficacy agents that are not included in current Asthma guidelines
      2. Consider using on regular schedule 2-4 times daily
      3. Cromolyn (Intal)
      4. Nedocromil (Tilade)
        1. Discontinued in U.S. in 2008 after CFC ban
    3. Step 3: Inhaled Corticosteroid trial (preferred in underlying Asthma)
      1. Obtain initial Exercise challenge with PFTs
      2. Inhaled Corticosteroid (e.g. Qvar, Pulmicort, Flovent, Asmanex) for 4 weeks
      3. Obtain follow-up Exercise challenge with PFTs
      4. Continue Inhaled Corticosteroid if benefit seen
      5. Consider in combination with inhaled Long-Acting Beta Agonist (e.g. Advair)
    4. Step 4: Ipratropium Bromide (Atrovent)
      1. Inhaled 2 puffs up to qid
    5. Other interventions with unproven benefit
      1. Vitamin C 2 grams before Exercise
      2. Dietary salt reduction
      3. Omega 3 Fatty Acid supplementation
    6. Avoid Long-Acting Beta Agonists (e.g. Salmeterol) in Exercise-Induced Asthma (unless Moderate Persistent Asthma)
      1. Consistent use results in worsening symptoms and decreased short-acting Bronchodilator (rescue Inhaler) effect
      2. If Long-Acting Beta Agonists are used in Exercise-Induced Asthma, avoid use >3 days per week

X. Medications: Sporting organization rules regarding restricted medications for Asthma

  1. Organizations
    1. United States Olympic Committee (USOC)
    2. National Collegiate Athletic Association (NCAA)
  2. No approval needed
    1. Ipratropium Bromide
    2. Leukotriene Modifiers
      1. Montelukast (Singulair)
      2. Zafirlukast (Accolate)
    3. Theophylline
    4. Mast Cell Stabilizers
      1. Cromolyn (Intal)
      2. Nedocromil (Tilade)
  3. Prior approval required
    1. Inhaled Corticosteroids (requires declaration of use by USOC)
    2. Inhaled Beta Agonist (permitted only with prescription by NCAA, USOC)
      1. Albuterol (Proventil, Ventolin)
      2. Pirbuterol (Maxair)
      3. Terbutaline (Brethine)
      4. Salmeterol (Serevent)
  4. Prohibited
    1. Oral (not inhaled) beta 2 Agonists

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