Exercise poses respiratory risks in patients with fibrotic ILD

Exercise in patients with interstitial lung disease (ILD) may result in thoracoabdominal asynchrony (TAA) and higher recruitment of inspiratory accessory muscle, suggests a study.

In addition, “TAA during exercise occurred in more severely restricted ILD patients and was associated with exertional dyspnoea, desaturation, and limited exercise performance,” the authors said.

In this study, the authors compared breathing pattern, respiratory mechanics, TAA, and respiratory muscle recruitment in 31 fibrotic ILD patients and 31 health controls at rest and during incremental exercise. TAA was defined as phase angle >20 °.

Fibrotic patients showed increased and early recruitment of inspiratory rib cage muscle (p<0.05) and an increase in phase angle, which indicated TAA, during exercise as compared with controls. TAA occurred more frequently in fibrotic ILD patients than in controls, both at 50 percent of the maximum workload (42.3 percent vs 10.7 percent; p=0.01) and at the peak (53.8 percent vs 23 percent; p=0.02).

Furthermore, fibrotic ILD patients with vs without TAA demonstrated lower lung volumes (forced vital capacity; p<0.01), greater dyspnoea (Medical Research Council >2 in 64.3 percent; p=0.02), worse exercise performance (lower maximal work rate % predicted; p=0.03; lower tidal volume; p=0.03; greater desaturation and dyspnoea; p<0.01), and higher oesophageal inspiratory pressures with lower gastric inspiratory pressures and higher recruitment at scalene (p<0.05).

“The precise coordination of respiratory muscles during exercise minimizes work of breathing and avoids exercise intolerance,” the authors said. “Fibrotic ILD patients are exercise-intolerant.”