Abstract
Chronic Obstructive Pulmonary Disease (COPD) patients can develop autonomic nervous system dysfunction (ANSd) during the curse of the disease. Although heart rate recovery (HRR) measured immediately after exercise is considered an ANS marker easy to evaluate, the cutoff point to establish dysfunction remains unclear. Our hypothesis is that the slope of the HRR kinetics after exercise (HRRk) is a simple and useful index to evaluate ANSd in COPD.
HRRk after a constant work-rate cycloergometer exercise was recorded before and after 8 weeks of endurance training in 10 COPD patients (FEV1: 47±8%pred; 71±3 yrs) and 10 healthy controls (66±10 yrs). To calculate HRRk, the heart rate during the recovery period was normalized to range from 1 at the end of the exercise to 0 at minute 6 of the recovery period.
At baseline, the slope of the HRRk was significantly higher in the control group than in the COPD group (p<0.001). Thus, the HRR at the first minute after exercise was lower in the COPD group (mean 11 beats) than in the control group (21 beats) (p<0.001). After training, the HRRk slope increased in the control group (from 0.009 to 0.012) (p<0.05) but no changes were seen in COPD patients (from 0.007 to 0.008).
We conclude that HRR kinetics after exercise enhances assessment of ANSd in COPD patients.
Supported by FIS PI061510; UE – FP7 (CIP-ICT) 225025.
- © 2011 ERS
