Are Pulmonary Function Tests Important for Runners?
Standard baseline pulmonary function tests (PFTs) alone are not sufficient for runners—instead, exercise challenge testing with serial post-exercise spirometry is the critical diagnostic tool for detecting exercise-induced bronchoconstriction (EIB), which affects up to 10-20% of athletes and is frequently asymptomatic. 1
Why Baseline PFTs Are Inadequate
Normal resting spirometry does not exclude EIB in runners. Athletes with significant exercise-induced airway narrowing routinely have completely normal baseline lung function. 1, 2
Symptoms are unreliable for diagnosis. Studies demonstrate that 36% of college athletes without respiratory symptoms had positive exercise challenges (≥10% FEV1 decline), while 35% with symptoms had negative tests. 1
Self-reported symptoms have poor predictive value. Among elite athletes, 91% of those with positive exercise tests and 48% of those with normal tests reported at least one EIB symptom, making symptoms neither sensitive nor specific. 3
The Essential Diagnostic Approach
Standardized exercise challenge testing with post-exercise spirometry is mandatory for diagnosing EIB in runners. 1, 2
Exercise Challenge Protocol Requirements:
Exercise intensity: Must achieve and sustain ≥85% maximum heart rate in adults or ≥95% in elite athletes for at least 4 minutes. 1, 2
Duration: 6-8 minutes total exercise time after 2-4 minutes of warm-up. 1, 2
Environmental conditions: Temperature 20-25°C with relative humidity <50% using dry compressed air to maximize sensitivity. 1, 2
Post-exercise measurements: FEV1 measured at 1,3,5,7,10,15, and 20 minutes after exercise cessation. 1
Diagnostic threshold: ≥10% fall in FEV1 from baseline at any two consecutive time points is diagnostic. 1, 2
Medication Withholding Requirements:
- Short-acting bronchodilators: 6 hours before testing 1, 2
- Long-acting bronchodilators: 24 hours before testing 1, 2
- No steroids or caffeine on test day 1, 2
Alternative Testing Options
Eucapnic voluntary hyperpnea (EVH) is more sensitive than methacholine challenge for detecting EIB in athletes. 1, 2
Methacholine testing has only 36% sensitivity for identifying positive EVH results, despite excellent negative predictive value. 1
Indirect challenges (exercise, EVH, mannitol) are strongly preferred over direct challenges (methacholine) for athletic populations. 1
Critical Pitfalls to Avoid
Field-based exercise testing without controlled conditions produces high false-negative rates. In one study, 78% of athletes who tested positive during field-based challenges were negative during laboratory testing with inadequate environmental stress. 3
The testing environment is crucial: Runners who train in cold, dry air or high-allergen environments have higher EIB prevalence, and testing must replicate these conditions to achieve diagnostic sensitivity. 1, 3
Distance runners specifically are at elevated risk due to sustained high ventilation rates and exposure to environmental triggers like ozone and allergens during training. 1
When Testing Is Most Important
Testing should be prioritized for runners who:
Report any respiratory symptoms during or after exercise (cough, wheeze, chest tightness, dyspnea), recognizing these symptoms have poor specificity 1, 2
Compete at elite levels, where EIB prevalence reaches 30% in certain endurance sports 1
Train in cold environments, where prevalence approaches 60% in Nordic skiing athletes 1
Have unexplained performance limitations despite adequate training 1, 4
The Bottom Line for Clinical Practice
Do not treat runners empirically with bronchodilators based on symptoms alone—confirmatory exercise challenge testing is required. 4 A baseline PFT may be reasonable for initial screening, but negative results should never exclude EIB in symptomatic or high-risk runners. 2, 4 The diagnostic standard remains standardized exercise challenge testing performed under controlled laboratory conditions with appropriate environmental stress and serial post-exercise spirometry. 1, 2