Table 2 Most common differential diagnoses of exercise-induced asthma (EIA) in athletes
ConditionSymptoms and occurrencePhysical signsObjective evidenceOther useful tips
EIA/EIBChest tightness, wheezing, cough and shortness of breath generally occurring within 5 to 30 min after intense exercise (sometimes during)Expiratory dyspnoea Expiratory rhonchi or wheezingReversibility on lung function testing Increased airway responsiveness in provocation challengesImprovement occurs either spontaneously or after inhaled bronchodilator
Vocal cord dysfunctionThroat tightness, shortness of breath, increased inspiratory effort, stridor and wheeze Only during maximum exercise, and stopping right after (unless hyperventilation) Most often occurs in well-trained teenage girlsStridor audible inspiratory sounds from the laryngeal area without signs of bronchial obstructionFlattened inspiratory flow–volume loop during stridorNo effect of asthma medication Consider direct fibreoptic laryngoscopia during exercise to check for paradoxical vocal cord movement and to differentiate from laryngomalacia
Exercise-induced arterial hypoxaemiaOccurs in well-trained athletes with high VO2,maxRespiratory distressReduction in arterial oxygen saturationPrimarily due to diffusion limitations and ventilation/perfusion mismatch
Swimming-induced pulmonary oedemaShortness of breath and cough during or immediately after swimming associated with evidence of pulmonary oedemaSputum production Haemoptysis reduction in arterial oxygen saturation Respiratory distressNo or restrictive spirometric pattern persisting for up to 1 weekCrackles, rattling or “junky” feelings deep in the chest associated with breathing effort and cough
Exercise-induced hyperventilation (pseudo-asthma syndrome)Dyspnoea and chest tightness during exerciseHyperventilationIncreased end-tidal carbon dioxideSymptoms are not directly related to bronchial obstruction but with hypocapnia and a possible abnormal ventilatory homeostasis during exercise
Poor physical fitnessDyspnoea and muscular stiffness related to expectations and training levelHigh heart rate after low-grade exercise loadNormal lung function and negative provocation challengesExercise rehabilitation or training can improve aerobic fitness and endurance and can shift the lactate/ventilatory threshold so more work is required before lactate accumulates and ventilation increases Improved aerobic fitness through exercise training can thus decrease the hyperpnoea and dyspnoea associated with exercise
  • EIB: exercise-induced bronchoconstriction; VO2,max: maximum oxygen uptake.