Functional Recovery Patterns and Exercise Tolerance in Children With Persistent Asthma: An Observational Study Using Spirometry and the Six-Minute Walk Test (6MWT)

Background Bronchial asthma in children is associated with progressive airway inflammation and variable functional limitation. While spirometry remains central to disease assessment, functional exercise capacity may not parallel physiological impairment. Data describing short-term functional recovery using combined spirometric and exercise-based assessment in children with asthma are limited. Methods This observational study with a short-term follow-up component was conducted at a tertiary care pediatric center in Chennai between April 2021 and August 2022. Children aged 6-12 years with bronchial asthma diagnosed according to Global Initiative for Asthma (GINA) criteria were enrolled. Children with asthma controlled with low-dose inhaled corticosteroids or short-acting beta-agonists as needed were categorized as having mild asthma. Those requiring medium-dose inhaled corticosteroids or long-acting beta-agonists were categorized as moderate asthma, and children with high-dose inhaled corticosteroids or long-acting beta-agonists were categorized as severe asthma. Pulmonary function was assessed using standardized spirometry in accordance with American Thoracic Society/European Respiratory Society 2019 guidelines, and functional capacity was evaluated using the six-minute walk test (6MWT). Spirometric parameters and 6MWT performance were compared across asthma severity categories using appropriate statistical tests. Children with abnormal baseline forced vital capacity (FVC) were offered repeat spirometry at three months. Results A total of 250 children with asthma were included, with a male-to-female ratio of 1.5:1. Spirometric impairment demonstrated a stepwise worsening with increasing asthma severity, with the most pronounced abnormalities observed in severe asthma. In contrast, six-minute walk performance remained largely preserved across severity groups. Comparative analysis showed significant differences in the distribution of abnormal FVC values between mild and severe and between moderate and severe asthma categories. Among the 57 children with abnormal baseline FVC who completed follow-up, spirometric improvement was observed in most children with mild and moderate asthma, whereas recovery was limited in those with severe asthma. Conclusions Spirometric impairment in children with asthma worsens progressively with disease severity, whereas functional walking capacity remains relatively preserved until later stages. These findings highlight a dissociation between physiological airflow limitation and functional exercise tolerance. Integrated monitoring strategies combining spirometry with functional assessment may provide a more comprehensive evaluation of pediatric asthma and support optimized follow-up and management.