Beneficial Effect of Water-Based Exercise Training on Exercise Capacity in COPD Patients—a Pilot Study

Background: Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable condition, characterized by persistent airflow limitation. Exercise training is a core component of pulmonary rehabilitation in people with COPD. Water-based exercise has been studied, but it remains unclear whether water-based exercise program leads to the improvement in respiratory function, muscle strength, balance ability, and exercise capacity. We aim to study the effect of an 8-week water-based exercise program on respiratory function, muscle strength, balance ability, and exercise capacity in people with COPD. Methods: Fourteen stable COPD participants (FEV(1) 56.8 ± 24.6%pred) were recruited and randomized into a water-based exercise or a land-based exercise group. Both groups were trained for 8 weeks, two sessions per week. Pulmonary function, respiratory muscle strength, peripheral muscle strength, balance ability, exercise capacity [6-min walking test (6MWT), incremental shuttle walk test (ISWT), and endurance shuttle walk test (ESWT)] were assessed at baseline and at the end of the program. ANCOVA was used to conduct between-group comparisons of outcomes after adjusting for pre-intervention values. Results: Baseline characteristics of participants were not significantly different between the two groups (p ≥ 0.05). After the 8-week training program, participants in the intervention group achieved larger gains in ESWT (Δ663.4 ± 279.5 vs. Δ45.4 ± 93.2 s, p = 0.001). In addition, maximal inspiratory pressure (MIP) was significantly increased more in the intervention group (Δ11.1 ± 7.8 vs. Δ1.1 ± 5.7 cmH(2)O, p = 0.026). However, no significant differences in pulmonary function, peripheral muscle strength, balance ability variables, 6MWD (p = 0.248), and ISWT (p = 0.506) were observed between the two groups. Conclusions: The water-based exercise program could be recommended to the COPD rehabilitation program for improving the endurance exercise capacity and inspiratory muscle strength. Clinical Trial Registration: www.thaiclinicaltrials.org, identifier: TCTR20210125005.