High intensity interval training in interstitial lung disease: a randomized controlled trial

Pulmonary rehabilitation (PR) is an effective guideline-recommended intervention for people with interstitial lung disease (ILD). However, not all participants experience clinically meaningful improvements. The current PR approach may not represent the optimal form of exercise training for people with ILD.

To compare the effects of high intensity interval training (HIIT) with the standard PR method of moderate intensity continuous training (MICT) in fibrotic ILD (fILD).

131 participants with fILD were randomized, stratified for exertional desaturation (SpO2 < or ≥ 90%), to undertake HIIT or MICT during a standard 8-week, twice-weekly PR program. Cycle endurance time (primary outcome), 6-minute walk distance (6MWD), symptoms, health-related quality of life, skeletal muscle changes, and physical activity levels assessed at baseline, immediately after PR, and 6-months were compared between groups using linear mixed models and intention-to-treat analysis.

Clinically important improvements in cycle endurance time were evident following PR for HIIT and MICT with no between-group difference (MD -63s, 95%CI -195 to 68s). A similar response was seen for 6MWD (MD 4m, 95%C1 -20 to 28m) and all secondary outcomes with no difference between HIIT and MICT. There were no adverse events in either group. A similar proportion of participants in each group completed PR, achieved the prescribed intensity, duration and progression.

HIIT did not result in greater improvements in exercise endurance than MICT in people with fILD. HIIT was safe and well-tolerated, and may serve as an alternative to MICT in people with fILD.