The response to exercise in normal and asthmatic children

Area of Science:

• Pediatric Pulmonology
• Exercise Physiology
• Respiratory Medicine

Background:

• Exercise-induced bronchospasm (EIB) is a common condition in children with asthma.
• Accurate identification of EIB is crucial for effective asthma management.
• Various pulmonary function tests can assess exercise-induced changes.

Purpose of the Study:

• To evaluate the sensitivity of different pulmonary function tests in detecting exercise-induced bronchospasm in asthmatic children.
• To compare the diagnostic yield of various lung function parameters following standardized exercise challenges.

Main Methods:

• A cohort of 105 asthmatic children and 25 normal children underwent treadmill exercise.
• Pulmonary function tests, including PEFR, FEV1, MMEF, V50, and V25, were measured before and after exercise.
• The maximum percentage fall from resting values was calculated for each parameter.

Main Results:

• In normal subjects, maximal falls from resting values varied by test: PEFR 12.5%, FEV1 10%, MMEF 26%, V50 30%, V25 33%.
• PEFR and FEV1 identified 99% of asthmatic children with a positive exercise response.
• MMEF showed the largest fall (26%) but detected only 70% of positive responders; pre-exercise function influenced incidence, not severity.

Conclusions:

• Peak Expiratory Flow Rate (PEFR) and Forced Expiratory Volume in 1 second (FEV1) are highly sensitive and reliable for diagnosing exercise-induced bronchospasm in children.
• While MMEF demonstrates larger changes, PEFR and FEV1 offer superior diagnostic utility for identifying EIB in pediatric populations.
• Pre-exercise pulmonary function impacts the likelihood of developing EIB but not its intensity.