Objective: To investigate proper methods and parameters of exercise intensity in pulmonary rehabilitation for patients with chronic obstructive pulmonary disease (COPD).
Methods: Symptom-limited cardiopulmonary exercise test (CPET) was performed in 30 male patients with moderate to severe COPD by cycle ergometer. Exercise intensity parameters, including the measured heart rate reserve (HRR%meas), the predictive heart rate reserve (HRR%pred) and the Borg scale were obtained. The distribution of these parameters ranged from 10% to 90% VO2max were compared. Multiple regression analysis was applied to analyze the relationship among heart rate (HR), the Borg scale and VO2max%.
Results: The HRR%meas was close to VO2max%. The coefficient of variation (CV) of HRR%meas was larger than HRR%pred. The larger was the Borg scale, the smaller was the distribution of VO2max%. While the Borg scale were 3, 4, and 5, the exercise intensity achieved 60%, 72%, and 78% VO2max, respectively. Predicted equation (VO2max%=1.026xHR+27.688xBorg-0.179xHRxBorg-63.313, r=0.920, P=0.00) was obtained.
Conclusion: HRR%meas was a better parameter than HRR%pred for prescribing the exercise intensity. The Borg scale is a simple and applicable method to prescribe and monitor the exercise intensity. It is suggested that Borg scale should reach 4 (moderate dyspnea) in pulmonary rehabilitation for the male patients with moderate to severe COPD. Predicted equation for VO2max% is recommended for monitoring the exercise intensity.