Predictors of improvement in resting heart rate after exercise training in patients with chronic obstructive pulmonary disease.

BACKGROUND High resting heart rate (RHR) is associated with multiple morbidity in chronic obstructive pulmonary disease (COPD) patients. Factors regarding the effectiveness of exercise training (ET) on RHR in COPD patients are unclear. AIMS The main objective of the current study is to determine the predictors of the eventual change in RHR after ET. METHODS One hundred and ten COPD patients (mean age: 63.1 ± 8.1 years, FEV1%: 43.6 ± 16.6) who participated in the ET program that consisted of supervised breathing, aerobic, strengthening, and stretching exercises for 8 weeks, 2 days a week, were included in the study. RHR, pulmonary functions, 6-min walk distance (6-MWD), Modified Medical Research Council Dyspnea Scale, St. George Respiratory Questionnaire, and Hospital Anxiety and Depression scores were compared before and after ET. Multivariate regression analysis was performed to correlate factors related to changes in RHR before and after exercise. RESULTS There was a significant improvement in RHR after the ET program (p < 0.001). Improvement in RHR was correlated with baseline RHR, 6-MWD, partial arterial oxygen pressure, dyspnea sensation, forced expiratory volume in the first second (r = 0.516, -0.388, -0.489, 0.369, -0.360, p < 0.05, respectively), and change in 6-MWD, partial arterial oxygen pressure, and symptom score (r = 0.523, 0.451, -0.325, p < 0.05, respectively) after ET. Baseline RHR, 6-MWD, and the change in 6-MWD were the independent factors that predicted the change in RHR after ET. CONCLUSIONS Patients with a high RHR and low functional capacity and whose functional capacity improves more have a greater decrease in RHR after the ET program. By considering these related factors, clinicians can focus on improving the cardiovascular system in COPD patients. CLINICAL TRIAL NUMBER NCT04890080 (retrospectively registered-date of registration: 05.17.2021).