Cardiopulmonary rehabilitation enhances heart rate recovery in patients with COPD.
BACKGROUND
Autonomic dysfunction is present early in the course of 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 subjects with COPD who participated in a 36-session exercise-based cardiopulmonary rehabilitation program. Subjects 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 subjects (age 66.3 ± 7.8 y, 90% male, body mass index 27.1 ± 4.1 kg/m(2), FEV(1) 45.7 ± 18.7%) completed the program. In these subjects, heart rate recovery increased from 16.2 ± 8.0 beats/min to 18.4 ± 8.4 beats/min (P = .01), resting heart rate decreased from 88.0 ± 10.7 beats/min to 83.3 ± 10.5 beats/min (P = .004), and heart rate at anaerobic threshold decreased from 109.0 ± 12.5 beats/min to 105.5 ± 11.7 beats/min (P = .040). In addition, oxygen consumption (V(O(2))) increased from 14.3 ± 3.7 mL/kg/min to 15.2 ± 3.8 mL/kg/min at peak exercise, and from 9.7 ± 2.4 mL/kg/min to 10.4 ± 2.6 mL/kg/min at anaerobic threshold (both P = .02), while the V(O(2))/t slope increased from -0.32 ± 0.16 mL/kg/min(2) to -0.38 ± 0.19 mL/kg/min(2) (P = .003). Parameters of ventilatory performance improved also.


CONCLUSIONS
In subjects with COPD, exercise-based rehabilitation improves heart rate recovery, modestly though, which indicates a degree of attenuated autonomic dysfunction. Exercise and muscular oxidative capacity, as expressed by V(O(2))/t slope, is also improved.
First Critical Care Medicine Department, National and Kapodistrian University of Athens, Greece.
Vasiliki V
VV
Georgiopoulou
Stavros
S
Dimopoulos
Dimitrios
D
Sakellariou
Ourania
O
Papazachou
Vasiliki
V
Gerovasili
Athanasios
A
Tasoulis
Varvara
V
Agapitou
Ioannis
I
Vogiatzis
Charis
C
Roussos
Serafim
S
Nanas
D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012129:Respiratory Function Tests