Much of our knowledge about how balneotherapy works physiologically has come from a variety of studies and clinical trials conducted since the 1950s. Unfortunately, conclusive data has been slow to emerge. One reason has to do with the difficulty in setting up "blinded" studies. Blinding refers to the practice of keeping both researchers and study participants in the dark about who is receiving the treatment under study and who is receiving the placebo treatment. In the case of balneotherapy, it's difficult to veil the treatment study when the water used in the study is hot, buoyant or smells of sulfur.
Still, researchers have pushed on, doing their best to reduce observer bias, reporter bias and the placebo effect. To date, the most conclusive studies demonstrating the therapeutic effect of balneotherapy have been those focused on musculoskeletal disorders. A recent review of relevant randomized controlled studies revealed that balneotherapy resulted in statistically significant pain improvement in patients with rheumatic diseases and chronic low back pain. Rheumatic diseases affect joints and connective tissues and include more commonly known conditions such as rheumatoid arthritis and osteoarthritis. They also include fibromyalgia, a syndrome of conditions characterized by widespread pain in muscles and connective tissues, and ankylosing spondylitis, a chronic inflammatory disease of the spine and pelvis.
Another promising area of research has focused on the effects of balneotherapy on dermatological conditions. There is growing evidence that water-based treatments benefit patients with psoriasis, a condition marked by uncontrollable skin cell growth, and atopic dermatitis, a type of eczema in which the skin becomes irritated and inflamed. Scientists are also studying balneotherapy as a treatment for acne, rosacea and seborrhea.
Over the next few years, research may show that balneotherapy can do much more than treat ailments of the skin, bones and muscles. Studies are already under way to investigate the effectiveness of water as a therapy for cardiovascular and neurological disorders. For example, deep breathing exercises conducted in heated pools may be beneficial to people with chronic obstructive pulmonary disease (COPD). And very preliminary results from one trial indicate that repeated sauna therapy may protect against oxidative stress, which leads to the prevention of atherosclerosis. If this research bears fruit, the medical advice we are likely to hear in the future is, "Take a hot bath and call me in the morning."