Evidence-based effects of various hydrotherapy on pulmonary function: A systematic review

Background

Impaired pulmonary function is an indicator of cardiopulmonary and all-cause mortality. Hydrotherapy is employed to manage various respiratory diseases through its potential mechanisms (i.e., temperature-induced vasodilation, bronchodilation, and muscle relaxation). There is a paucity of systematic reviews examining its impact on pulmonary function and the existence of various clinical trials exhibiting the potential role of hydrotherapy in improving respiratory health, which demands to explore the effectiveness of hydrotherapy on pulmonary function. Therefore, the objective of this systematic review was to evaluate the effects of various hydrotherapeutic modalities (i.e., balneotherapy, aquatic exercise, baths, and packs) on pulmonary function along with its mechanistic pathways.

Methods

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used for this review. An extensive literature search was conducted across the PubMed/Medline and Cochrane Library databases from their inception until August 2023, using keywords related to hydrotherapy and pulmonary function. This search identified 439 articles. Upon screening, 10 studies were finalized that met the eligibility criteria including experimental studies such as randomized controlled trials (RCTs), crossover or self-as-control trials, single group pre-post trials reporting the hydrotherapy’s effect on pulmonary function test, excluding observational studies, case reports, case series, review articles, surveys, and health news.

Results

This review included 10 studies (3 RCTs, 1 randomized cross-over trial, 1 non-RCT, 1 quasi-experimental study, 3 single group pre and post-test, and, 1 cross-sectional study) with 394 participants and assessed the effects of various hydrotherapy (hot chest pack, steam bath, immersion bath, balneotherapy, aquatic therapy) on pulmonary function. Results imply that the application of water at different temperatures has beneficial effects in improving various spirometric outcomes (FEV₁, FVC, FEV₁/FVC, PEFR) in healthy individuals, COPD, scoliosis, musculoskeletal and neuromuscular disorders.

Conclusion

This systematic review suggests that hydrotherapy has potential benefits in improving pulmonary function either as a solitary or adjuvant therapy in healthy individuals and patients with COPD, spinal cord injury, neuromuscular disorders, scoliosis, and musculoskeletal disorders. However, the lack of RCTs, small sample size, and the heterogeneity in the included participants and interventions are limiting the scope of this review. Future studies can aim at conducting long-term RCTs with a larger sample size and standardized interventions.