[Comparison of high-intensity and anaerobic threshold programs in rehabilitation for patients with moderate to severe chronic obstructive pulmonary disease]

Abstract

Objective: To compare two training programs in rehabilitation for patients with moderate to severe chronic obstructive pulmonary disease (COPD).

Methods: Of the 54 patients who entered the study, 41 completed the rehabilitation program. Thirty-two COPD patients were randomly assigned to either the anaerobic threshold group (AT, n = 15) or the high-intensity group (HI, n = 17). Another group was the control group (NT, n = 9). Bicycle exercise training was conducted for 2 days each week for a period of 12 weeks. The HI group received the highest level of intensity that could be tolerated. The AT group received a training intensity corresponding to the anaerobic threshold. Main assessments included lung function test, cardiopulmonary exercise testing, the St George's Respiratory Questionnaire and the Borg dyspnea scale before and after the rehabilitation program. The data of the baseline clinical characteristics of groups were presented as (-x) +/- s. Comparison within two means were analysed through one-sample t test or paired t test. One-way analysis of variance was used to compare multiple means. The rates were analysised by Fish exact probabilities. The Wilcoxon rank sum test was used for comparisons within the groups and the Mann-Whitney u test for intergroup comparisons.

Results: Both the AT and HI groups showed significant improvement in Vo(2peak)% pre after rehabilitation, with the former increasing from (61 +/- 11)% to (69 +/- 14)%, and the latter increasing from (72 +/- 12)% to (79 +/- 13)%. The degree of improvement of both groups (AT and HI) were (14 +/- 17)% and (12 +/- 13)%, the difference being not significant (z = -0.180, P > 0.05). At 56 W work rate, the minute ventilation decreased from (36 +/- 4) L/min to (33 +/- 5) L/min (t = 6.167, P < 0.01), the breathing frequency decreased from (32 +/- 1) beats/min to (31 +/- 3) beats/min (t = 2.876, P < 0.05), and the tidal volume increased from (1.2 +/- 0.3) L to (1.3 +/- 0.3) L (t = 2.587, P < 0.05) in the HI group. After rehabilitation the heart rates [(109 +/- 39, 110 +/- 25) beats/min] were significantly lower than those of the baseline [(116 +/- 39, 114 +/- 42) beats/min] respectively in the AT and the HI groups. Oxygen pulse increased significantly from baseline (9.6 +/- 3.7, 8.5 +/- 4.3) ml/beat to (10.4 +/- 4.0, 9.0 +/- 3.2) ml/beat. This level of exertional dyspnea (DeltaBorg/DeltaVo(2)) was significantly improved from (8.6 +/- 3.2, 6.5 +/- 2.6) to (7.4 +/- 2.5, 5.6 +/- 2.4) in both the HI and the AT group (both P < 0.05). The between-group difference for the change in DeltaBorg/DeltaVo(2), however, was not significant (z = -0.378, P > 0.05).

Conclusions: Both the HI and the AT groups had significant improvements in exercise capacity and dyspnea after pulmonary rehabilitation. The degree of improvement in both groups was similar. But the HI group showed significant improvement in the anaerobic threshold and decrease in ventilatory requirement.