Home-based, remotely supervised, high-intensity interval training and cardiorespiratory fitness in children and...

While high-intensity interval training (HIIT) has shown effectiveness in improving cardiorespiratory fitness (CRF) across various chronic respiratory diseases, its impacts on individuals with post-infectious bronchiolitis obliterans (PIBO) remain unexplored. Our aim was to assess the effects of a home-based, remotely supervised, HIIT programme on CRF, clinical and functional variables in patients with PIBO.

Participants of this assessor-blinded, multicentre, randomised controlled trial were individuals with PIBO aged 6-20 years. An exercise (EXE) group underwent two 40-min sessions of HIIT remotely supervised in real time per week. Sessions were continued for 16 weeks. The control (CON) group adhered to general physical activity recommendations. The primary outcome was peak oxygen uptake (V̇ _{O2 peak}), time to first ventilatory threshold (VT₁), percentage of V̇ _O2 at VT₁ and ventilatory equivalent for carbon dioxide, determined via cardiopulmonary exercise testing on a treadmill. Secondary outcomes were lung function (spirometry), muscle strength (dynamometry), functional capacity (30-s sit-to-stand (30s-STS) test), body mass index and St George's Respiratory Questionnaire score.

51 PIBO patients were enrolled (EXE group n=25; CON group n=26) (49% females; mean±sd age 13.3±4.2 years; forced expiratory volume in 1 s -3.56±1.28 (z-score); V̇ _{O2 peak} 36.8±8.6 mL·kg^-1·min^-1). The HIIT intervention resulted in improvements in V̇ _{O2 peak} (mean difference 3.39 mL·kg^-1·min^-1; p=0.04), time to VT₁ (mean difference 1.05 min; p=0.04) and number of repetitions in the 30s-STS test (mean difference 2.21 repetitions; p=0.04). No differences were found in the other variables.

Our real-time, remotely supervised HIIT intervention was effective at significantly increasing CRF and functional capacity in children and adolescents with PIBO.