Georgiopoulou VV, Dimopoulos S, Sakellariou D, Papazachou O, Gerovasili V, Tasoulis A, Agapitou V, Vogiatzis I, Roussos C, Nanas S.
Respir Care. 2012 Jun 15. [Epub ahead of print]

Abstract
BACKGROUND: Autonomic dysfunction is present early in the course of chronic obstructive pulmonary disease (COPD) and is associated with adverse outcomes. We utilized heart rate recovery, a simple and validated index of autonomic balance, to investigate the effects of exercise training on autonomic dysfunction in patients with COPD. METHODS: We evaluated 45 stable patients with COPD who participated in a 36-session exercise-based cardiopulmonary rehabilitation program. Patients underwent maximal cardiopulmonary exercise testing at baseline and after completion of the rehabilitation program. We recorded exercise testing parameters and heart rate during rest, exercise, and recovery; heart rate recovery was calculated as heart rate at peak exercise minus heart rate at the first minute of recovery. RESULTS: Thirty-nine patients (age, 66.3±7.8 years; 90% male; body mass index, 27.1±4.1 kg/m2; forced expiratory volume in 1st sec [FEV1], 45.7±18.7%) completed the program. In these patients, heart rate recovery increased from 16.2±8.0 to 18.4±8.4 beats/min (p<0.05), resting heart rate decreased from 88.0±10.7 to 83.3±10.3 beats/min (p<0.01), and heart rate at anaerobic threshold decreased from 109.0±12.3 to 105.5±11.7 beats/min (p<0.05). In addition, oxygen consumption (VO2) increased from 14.3±3.7 to 15.2±3.8 mL/kg/min at peak exercise and from 9.7±2.4 to 10.4±2.5 mL/kg/min at anaerobic threshold (both p<0.05), while the VO2/t slope increased from -0.32±0.16 to -0.38±0.19 mL/kg/min² (p<0.01); parameters of ventilatory performance improved also. CONCLUSIONS: In patients with COPD, exercise-based rehabilitation improves heartrate recovery, modestly though, which indicates a degree of attenuated autonomic dysfunction. Exercise and muscular oxidative capacity, as expressed by VO2/t slope, are also improved.