For as long as I can remember, my grandmother suffered with painful, swollen joints from “rheumatism,” as she called it. (Only at the end of her life, when anti-DNA antibody tests became available, was she diagnosed with lupus.) And every summer, she “took the cure” – bathing in hot springs in Saratoga Springs, NY.

People since prehistoric times have sought hot springs for their healing powers, and the medicinal benefits of spas and warm-water soaks for arthritis have been borne out in modern times. In 2009, the Bulletin de l’Académie Nationale de Médecine published a review of 19 randomized clinical trials, concluding that spa therapy is recommended for chronic low-back pain, stabilized rheumatoid arthritis, fibromyalgia, ankylosing spondylitis and osteoarthritis. Studies in the French review found physical benefits – reductions in pain and medication, and improvements in function as well as quality of life.

Other studies also have found that warm water – and exercise in warm water – have benefits for quality of life and mood. A study published in BMC Musculoskeletal Disorders found that twice as many patients reported feeling much better after exercising in 95-degree water once a week for six weeks compared with those exercising on land, even though both groups did equally well in physical function.

These effects might result in part from reduced stress. Exercise itself has been shown to boost mood and the immune system’s ability to fight disease. Exercise combined with warm water in a relaxing environment may reduce the stress response and boost positive brain pathways that improve mood and immune responses.

On a particularly hectic trip to Budapest, Hungary, I sought out an old Turkish bath, just a short walk from my hotel. After paying my few coins at the front entrance, I passed an archeological display revealing the original Roman clay pipes, now replaced by modern copper ones. I emerged from the locker room into a small chamber. Through the steam I could see an octagonal, emerald pool surrounded by arches and columns, and lit by streams of multi-colored sunbeams from stained-glass skylights.

Men and women lounged on the pool’s wide steps, some bent under cascades of water pouring from ancient gargoyles’ mouths. The water felt surprisingly hot, and I soon drifted into a reverie, relaxing more completely than I had in months. This is how one needs to appreciate these spots, I thought, for the first time understanding why my grandmother had spent days in the warm springs of Saratoga.

If you can’t get to a hot spring or spa, you can get some of the same benefits from a warm bath in the evening. It won’t take the place of antirheumatic medication, but it can reduce pain, improve mood and, importantly, help bring healing sleep.

Esther M. Sternberg, MD, rheumatologist and researcher, is the author of Healing Spaces: The Science of Place and Well-being (2009, Harvard University Press).