Description

Exercise-induced hyperventilation may result in a sense of chest tightness that can be clinically confused with exercise-induced asthma. The presence of clinical and pulmonary function findings can help distinguish these two conditions. The authors are from the University of Iowa.


Findings

Exercise-Induced Asthma

Exercise-Induced Hyperventilation

symptoms associated with exercise

wheezing, cough, chest tightness

chest tightness

history

onset of respiratory disease in early childhood

no history of respiratory disease in early childhood

other causes inducing similar symptoms

other stimuli usually present

other stimuli usually absent

response to an inhaled beta-2 agonist

responds

does not respond

decrease in FEV1 after exercise

> 15%

< 15%

decrease in end tidal carbon dioxide (ET CO2) after exercise

< 15%

>= 15%

 

decrease in FEV1 after exercise in liters =

= ((FEV1 before exercise in liters) – (FEV1 after exercise in liters)) / (FEV1 before exercise in liters) * 100%

 

decrease in end tidal carbon dioxide after exercise in mm Hg =

= ((ET CO2 before exercise in mm Hg) – (ET CO2 after exercise in mm Hg)) / (ET CO2 before exercise in mm Hg) * 100%

 

where:

• A normal person shows < 15% change in FEV1 and < 15% change in ET CO2 with exercise.

• A person with mixed exercise-induced asthma and hyperventilation would have a > 15% drop in FEV1 and a >= 15% decrease in ET CO2.

 


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