Dyspnea and the affective response during exercise training in obstructive pulmonary disease

Background: Dyspnea (SOB), dyspnea-related anxiety (DA), and exercise performance have been shown to improve after exercise training in patients with Chronic Obstructive Pulmonary Disease (COPD). However, there are no published descriptions of the changes in dyspnea intensity or dyspnea-related anxiety during or across the exercise training sessions. Objectives: To describe and compare the differences in the patterns of change in SOB, DA, and exercise performance during 12 exercise-training sessions with and without nurse coaching. Methods: Forty-five dyspnea-limited patients with COPD were randomly assigned to nurse-monitored (ME) or nurse-coached exercise (CE). SOB and DA were rated on a 200 mm VAS every 2 minutes during each of 12 treadmill training sessions. Results: Warm-up, peak, cool-down, mean SOB, and peak SOB/stage remained constant over the exercise sessions, with increasing exercise performance for both groups over the 12 sessions (p < .001). There was a significant difference in the pattern of mean SOB over time between the ME and CE : group (p < .05). Mean, peak DA, and peak DA/stage showed a rapid decrease within the first 4 sessions (p < .05) with no significant differences between the groups. Warm-up and cool-down DA remained constant. There were targe intra- and inter-subject Variations in the rating of dyspnea and dyspnea-related anxiety within and across sessions. Conclusions: As theoretically proposed, both groups significantly decreased their DA over the training sessions. This decrease was early in the sessions and was not accompanied by a decrease in the SOB. In contrast, subjects maintained a nearly constant mean and peak SOB with increasing exercise performance, suggesting that people may have a dyspnea threshold above which they are unable to tolerate greater dyspnea. Description of the changes in dyspnea and the affective response during training need to be expanded, while studying the type and timing of strategies to enhance the improvement in dyspnea and dyspnea-related anxiety.