Cardiovagal baroreceptor sensitivity and peak oxygen consumption in chronic obstructive pulmonary disease (COPD)

Abstract

Patients with chronic obstructive pulmonary disease (COPD) typically have reduced exercise capacity (VO2peak) and cardiovagal baroreflex sensitivity (BRS). The underlying mechanism for lower BRS in COPD is unclear. Exercise training has been shown to increase VO2peak and BRS sensitivity. Therefore, it was hypothesized that lower BRS in COPD would be related to VO2peak. COPD patients (n=14; Mean FEV1=59.4±33.9%predicted, age=70.9±8.8) and healthy controls (n=8; Mean FEV1=104.0±12.5%predicted, age=67.5±5.1) were recruited. None had diagnosed cardiovascular disease, diabetes or sleep apnea. VO2peak data were obtained from a cardiopulmonary exercise stress test. On a separate day resting heart rate and beat‐by‐beat blood pressure were measured. BRS was determined using the sequence method. We found lower BRS (7.2±3.8 vs. 14.8±9.7ms/mmHg; P=0.01) and VO2peak (19.6±4.0 vs. 31.1±9.3mL/kg/min; P<0.001) in COPD, and a linear relationship in COPD and controls between VO2peak and BRS was observed (R2=0.24; P=0.02). Preliminary results indicate that the reduction of BRS is related to reduced exercise capacity in COPD. Funded by Canadian Institutes of Health Research.