II. Pathophysiology
- Hyperventilation of dry, cool air
- Loss of heat or water from lungs during Exercise
III. Epidemiology
- Occurs in 90% of Asthmatics
- May occur in as many as 29% of athletes
- Cold Weather athletes appear more susceptible
- Occurs in 50% of olympic cross country skiers
IV. Symptoms
- Timing
-
Exercise-related symptoms
- Shortness of Breath
- Wheezing
- Decreased Exercise endurance
- Chest tightness
- Cough
- Epigastric Pain
- Pharyngitis
V. Signs
- Cardiopulmonary exam normal at rest
- Exclude associated conditions (see differential diagnosis below)
VI. Differential Diagnosis
- Cardiovascular disorder
-
Lung disorder
- Chronic Asthma
- Chronic Obstructive Pulmonary Disease (COPD)
- Cystic Fibrosis
- Interstitial Lung Disease
- Pectus Excavatum
- Scoliosis
- Tracheobronchial malacia
- Head and neck disorders
- Chronic Sinusitis
- Allergic Rhinitis
- Nasal Polyps
- Septal deviation
- Vocal Cord Dysfunction
- Miscellaneous disorders
- Deconditioning or Obesity
- Myopathy
- Anxiety Disorder or Hyperventilation
VII. Diagnostics
- Obtain FEV1 or Peak Flow at rest (exclude Asthma)
-
Exercise Challenge with Pulmonary Function Testing
- Not required for classic presentation
- Most patients may be treated empirically
VIII. Management: General Measures
- Maintain regular Exercise for physical conditioning
- Warm up and cool down for 10 minutes before and after
- Exercise in humidified, warm environment
- Cover nose and mouth during Cold WeatherExercise
- Consider heat exchange mask (available at sporting good stores)
- Avoid Exercise within 2 hours following a meal
- Avoid Exercise in high allergen, ozone or pollution
IX. Management: Medications
- Treat related conditions
- Primary Agents
- Short-acting Beta Agonist (Albuterol, Pirbuterol)
- Use 2 puffs, 15-30 minutes before Exercise
- Short-acting Beta Agonist (Albuterol, Pirbuterol)
- Secondary Adjunctive Agents
- Step 1: Leukotriene Modifiers (preferred if comorbid Allergic Rhinitis)
- Taken on regular schedule
- Montelukast (Singulair)
- Zafirlukast (Accolate)
- Zileuton XR (Zyflo CR)
- Other Leukotriene Modifiers are preferred due to adverse effects including hepatotoxicity
- Step 2: Mast Cell Stabilizer 15 minutes before Exercise
- Mast Cell Stabilizers are low efficacy agents that are not included in current Asthma guidelines
- Consider using on regular schedule 2-4 times daily
- Cromolyn (Intal)
- Nedocromil (Tilade)
- Discontinued in U.S. in 2008 after CFC ban
- Step 3: Inhaled Corticosteroid trial (preferred in underlying Asthma)
- Obtain initial Exercise challenge with PFTs
- Inhaled Corticosteroid (e.g. Qvar, Pulmicort, Flovent, Asmanex) for 4 weeks
- Obtain follow-up Exercise challenge with PFTs
- Continue Inhaled Corticosteroid if benefit seen
- Consider in combination with inhaled Long-Acting Beta Agonist (e.g. Advair)
- Step 4: Ipratropium Bromide (Atrovent)
- Inhaled 2 puffs up to qid
- Other interventions with unproven benefit
- Vitamin C 2 grams before Exercise
- Dietary salt reduction
- Omega 3 Fatty Acid supplementation
- Avoid Long-Acting Beta Agonists (e.g. Salmeterol) in Exercise-Induced Asthma (unless Moderate Persistent Asthma)
- Consistent use results in worsening symptoms and decreased short-acting Bronchodilator (rescue Inhaler) effect
- If Long-Acting Beta Agonists are used in Exercise-Induced Asthma, avoid use >3 days per week
- Step 1: Leukotriene Modifiers (preferred if comorbid Allergic Rhinitis)
X. Medications: Sporting organization rules regarding restricted medications for Asthma
- Organizations
- United States Olympic Committee (USOC)
- National Collegiate Athletic Association (NCAA)
- No approval needed
- Prior approval required
- Inhaled Corticosteroids (requires declaration of use by USOC)
- Inhaled Beta Agonist (permitted only with prescription by NCAA, USOC)
- Prohibited
- Oral (not inhaled) beta 2 Agonists