Differences between swimming and running as stimuli for exercise-induced asthma

Area of Science:

• Pediatric Pulmonology
• Exercise Physiology
• Respiratory Medicine

Background:

• Exercise-induced asthma (EIA) is a common condition in children.
• Previous research suggests environmental factors like humidity influence EIA severity.
• The impact of exercise modality on EIA, independent of metabolic stress, requires further investigation.

Purpose of the Study:

• To compare the severity of exercise-induced bronchoconstriction (EIB) between running and swimming in children.
• To investigate the relationship between respiratory heat loss (RHL) and EIB severity.
• To determine if exercise type influences EIB severity under standardized metabolic conditions.

Main Methods:

• Thirteen children performed 6-minute exercise tests on a treadmill and tethered swimming.
• Exercise was conducted breathing air at room temperature with either 8% or 99% relative humidity.
• Ventilation, gas exchange, heart rate, and FEV1 were measured. RHL was calculated.

Main Results:

• Oxygen consumption and ventilation were similar across all exercise conditions.
• The post-exercise fall in FEV1 (delta FEV1) was significantly greater after running compared to swimming.
• Delta FEV1 correlated with RHL, and the difference between running and swimming remained significant at standardized RHL.

Conclusions:

• The type of exercise significantly influences the severity of exercise-induced asthma in children.
• Running appears to elicit a more pronounced bronchoconstrictive response than swimming, even when metabolic and thermal respiratory challenges are controlled.
• These findings highlight the importance of considering exercise modality when managing EIA.