Breathlessness is a common and distressing symptom in patients with chronic obstructive pulmonary disease (COPD) and fibrotic interstitial lung disease (ILD), particularly during exercise. Effective medical management of exertional breathlessness in people living with COPD and fibrotic ILD is challenging for healthcare providers and requires an understanding of its mechanisms. Thus, in this brief review we summarize recent advances in our understanding of the pathophysiological mechanisms of exertional breathlessness in COPD and fibrotic ILD.
The collective results of recent physiological and clinical trials suggest that higher intensity ratings of exertional breathlessness in both COPD and fibrotic ILD compared to healthy control individuals is mechanistically linked to the awareness of greater neural respiratory drive (quantified using inspiratory muscle electromyography) needed to compensate for pathophysiological abnormalities in respiratory mechanics and pulmonary gas exchange efficiency.
Any therapeutic intervention capable of decreasing intrinsic mechanical loading of the respiratory system and/or increasing pulmonary gas exchange efficiency has the potential to decrease the prevalence and severity of activity-related breathlessness and improve related clinical and patient-reported outcomes (e.g., exercise tolerance and health-related quality of life) by decreasing neural respiratory drive in people with COPD and fibrotic ILD.
aClinical Exercise & Respiratory Physiology Laboratory, Department of Kinesiology & Physical Education, Faculty of Education, McGill University
bResearch Institute of the McGill University Health Centre, Translational Research in Respiratory Diseases Program, Montréal, Quebec
cResearch Centre for Physical Activity and Health, McGill University
dDepartment of Physical Therapy, University of British Columbia
eCentre for Heart Lung Innovation, Providence Healthcare Research Institute, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada
Correspondence to Dennis Jensen, PhD, Department of Kinesiology and Physical Education, 475 Pine Avenue West, Montréal, Quebec, Canada, H2W 1S4. Tel: +1 514 398 4184; fax: +1 514 398 4186; e-mail: email@example.com