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Effects of water immersion on pulmonary function in asthmatics
Summary
Asthma patients experience increased air trapping when immersed and after exercise, potentially raising their risk of lung injury during diving. This study highlights their reduced pulmonary airflow and greater air trapping compared to healthy individuals.
Area of Science:
- Physiology
- Pulmonary Medicine
- Diving Medicine
Background:
- Asthma and immersion can both cause air trapping in the lungs.
- Asthmatics may have an elevated risk of pulmonary barotrauma (PBT) during ascent when using diving apparatus due to air trapping.
Purpose of the Study:
- To investigate pulmonary airflows and closing capacities in individuals with exercise-induced asthma (A) versus healthy controls (C).
- To compare respiratory function under dry and immersed conditions, before and after exercise.
Main Methods:
- Subjects included 12 asthmatics and 11 healthy controls.
- Pulmonary airflows and closing capacities were measured in four conditions: dry, immersed, pre-exercise, and post-exercise.
- Exercise involved treadmill running.
Main Results:
- Both groups showed reduced vital capacity, FEV1, FEV1/FVC, and FEF25%-75% when immersed.
- Post-exercise and immersed, asthmatics exhibited further deterioration in pulmonary airflow (FEV1, FEF25-75%) compared to controls.
- Asthmatics were more likely to show no closing volume phase IV when immersed post-exercise, suggesting increased air trapping.
Conclusions:
- Asthmatics demonstrate reduced pulmonary airflow during immersion after exercise.
- Increased air trapping in asthmatics during immersion post-exercise is indicated by the absence of closing volume phase IV.
- These findings suggest a heightened risk for asthmatics experiencing respiratory issues during diving activities, particularly after exertion.
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