Comparison of exercise capacity, respiratory and peripheral muscle strength and dyspnea in patients with interstitial lung disease with and without chronotropic incompetence

Abstract

Background: Reduced chronotropic response to maximal exercise has been associated with poor survival rates in patients with interstitial lung disease (ILD). There is limited study investigated the contribution of chronotropic response to exercise capacity, respiratory/peripheral muscle strength and dyspnea in patients with ILD. Aim: To compare functional and maximal exercise capacity, respiratory and peripheral muscle strength and dyspnea in patients with ILD with/without chronotropic incompetence (CI) ( Methods: Twenty two patients (50.5±14 years) with and 16 patients (49.8±13 years) without CI were compared. Chronotropic response index was calculated. Exercise capacity was measured using incremental shuttle walk (ISWT) and six minute walk tests (6MWT), pulmonary functions using spirometry, respiratory muscle strength using a mouth pressure device, peripheral muscle strength using a hand-held dynamometer and dyspnea using Modified Medical Research Council (MMRC) dyspnea scale. Results: Demographic characteristics, pulmonary functions and respiratory muscle strength were similar in groups (p>0.05). Patients with CI have significantly higher MMRC scores (p=0.007) and lower quadriceps femoris (p=0.033) and hand grip muscle strength (p=0.05), 6MWT (p=0.002) and ISWT distances (p=0.005). Conclusion: Patients with ILD with CI have decreased peripheral muscle strength, exercise capacity and increased dyspnea perception. Pulmonary rehabilitation programs should include aerobic exercise and peripheral muscle training programs to avoid chronotropic incompetence in ILD.