Hydrotherapy is a broad term that simply means the use of water for therapy. It includes several naturopathic methods, such as hot and cold baths, saunas, and balneotherapy. It also encompasses aquatic physical therapy, which is a specialized field within physical therapy that utilizes the buoyant force of water to support the patient’s body [1-3]. This article will discuss the theoretical framework of aquatic physical therapy, as well as research on the efficacy of the technique.
Water has a number of physical properties that can be manipulated for treatment purposes. Two properties that are important in hydrotherapy are buoyancy and temperature. When an object is placed in water, the downward force that it experiences due to gravity causes the object to displace some of the water. However, the water also exerts an opposing force on the object because it resists that displacement; this is the buoyant force. In the context of aquatic physical therapy (and general aquatic exercise), buoyancy reduces the pressure that a person’s musculoskeletal system typically experiences due to gravity, which can reduce joint pain and facilitate mobilization and/or strengthening exercises [1-4].
Physical therapy can also use water to more easily apply hot or cold conditions to the body. Cold temperatures are often applied to the body in order to reduce swelling and constrict blood vessels for acute treatment, such as after a sprain or intense exercise [1,4]. On the other hand, warm temperatures are often used to relax muscles and increase blood flow in peripheral tissues [1,3,4]. Aquatic physical therapy is often performed in warm water to add the benefit of those physiological effects. In addition, warm water and buoyancy are thought to activate thermoreceptors and mechanoreceptors, respectively, in a way that blocks or reduces pain signals [2-4].
Research on aquatic physical therapy is still somewhat limited, but available data suggest that the technique does have some positive effects. A randomized controlled trial compared the effects of exercise in warm water vs. on land in patients with rheumatoid arthritis. Interestingly, though the two groups showed similar improvements in measures of function, pain, and quality of life, the hydrotherapy group perceived greater improvement after treatment [5]. A phenomenon that may be related is that adherence to the treatment regimen appears to be relatively high for hydrotherapy [2].
Another study reviewed 13 randomized controlled trials of aquatic physical therapy in patients with osteoarthritis. Significant improvements in pain, disability, and quality of life were reported by 12, 12, and 10 of those trials respectively [6].
Kamioka et al. sought to evaluate the efficacy of both aquatic exercise and balneotherapy (bathing in water without exercise). Similarly, they found that aquatic exercise had small but statistically significant effects on pain and related outcomes for patients with locomotor diseases such as arthritis and low back pain. However, there was insufficient high-quality data on balneotherapy to make any conclusions [3].
Many patients who would benefit from physical therapy have conditions that make physical therapy challenging, such as joint pain that limits the mobility and load-bearing capacity of target joints. Standard physical therapy exercises typically work on strength and flexibility of the affected area. Aquatic physical therapy has several benefits that can help address these issues. Current data suggest that aquatic physical therapy may be appropriate for some patients, but additional research is needed to evaluate the long-term benefits of this treatment.
References
[1] “Types and Health Benefits of Hydrotherapy.” Health Essentials | Cleveland Clinic. November 5, 2021. https://health.clevelandclinic.org/what-is-hydrotherapy/
[2] “Aquatherapy.” Physiopedia. September 26, 2020. https://www.physio-pedia.com/Aquatherapy
[3] Kamioka, H., Tsutani, K., Okuizumi, H., et al. Effectiveness of Aquatic Exercise and Balneotherapy: A Summary of Systematic Reviews Based on Randomized Controlled Trials of Water Immersion Therapies. Journal of Epidemiology. 2010; 20(1): 2–12. doi: 10.2188/jea.JE20090030
[4] Mooventhan, A. & Nivithetha, L. Scientific Evidence-Based Effects of Hydrotherapy on Various Systems of the Body. North American Journal of Medical Sciences. 2014; 6(5): 199–209. doi: 10.4103/1947-2714.132935
[5] Lis Eversden, P., Maggs, F.,Nightingale, P., & Jobanputra, P. A pragmatic randomised controlled trial of hydrotherapy and land exercises on overall well being and quality of life in rheumatoid arthritis. BMC Musculoskeletal Disorders. 2007; 8: 23. doi: 10.1186/1471-2474-8-23
[6] Bartels, E. M., Juhl, C. B., Christensen, R., et al. Aquatic exercise for the treatment of knee and hip osteoarthritis. Cochrane Database of Systematic Reviews. 2016; 23(3): CD005523. doi: 10.1002/14651858.CD005523.pub3