The science of healing with water

October 8, 1999
Web posted at: 3:07 PM EDT (1907 GMT)

In this story: Easing the pain The Dead Sea cure Applying physiology RELATEDS

By Laird Harrison

(WebMD) -- The phone kept ringing; the kids kept screaming; your boss kept demanding. It's been one of those days. So after dinner, you fill the bathtub with hot water and settle in for a good, long soak. That's hydrotherapy -- therapeutic treatment that comes from the temperature and pressure of water.

It doesn't take a double-blind, placebo-controlled clinical trial to tell you that it works for a little relaxation. But scientists are just beginning to measure hydrotherapy's power in treating disease.

Easing the pain

According to some studies, the best candidates for hydrotherapy appear to be injured athletes.

"There have been lots of studies on sports injuries," says Kathleen Ferrell, a physical therapist at Washington University in St. Louis. "It has definitely been shown to relax and improve movement."

Arthritis patients, too, often receive hydrotherapy. The Arthritis Foundation recommends underwater exercise to prevent stiffening and atrophy. "Warm water increases blood flow to joints, plus the heat increases the flexibility of the joints," says Dr. John Klippel, medical director of the foundation. "And because of buoyancy, there is less force on the joint, so that one can exercise without pain."

People who have diabetes also might benefit from hydrotherapy, according to a report in the September 16 New England Journal of Medicine. Researchers from McKee Medical Center in Loveland, Colorado, described how eight diabetes patients lowered their glucose levels when they soaked in hot tubs a half-hour a day for six weeks. The study was too small to prove that hot water can truly treat diabetes, but the results may encourage further research.

The Dead Sea cure

Research has also been conducted on one type of balneotherapy (therapeutic treatment using chemicals in water). Since biblical times, people have gone to the Dead Sea between Jordan and Israel to heal arthritis and diseases of the skin. Study after study has documented dramatic healing in people with psoriasis, a chronic condition in which the skin becomes inflamed and scaled. Investigators theorize that these benefits come from minerals or tar in the salty water as well as the relatively high concentration of UVA rays in the local sunlight.

In 1990, researchers at Ben Gurion University in Israel wanted to test whether salts from the sea could treat rheumatism. They asked 15 rheumatics to take warm baths in which Dead Sea salts had been dissolved. Another 15 patients bathed in water mixed with ordinary table salt. Neither group knew which kind of salt was used. The Ben Gurion rheumatologists measured the strength of the patients' hand grips and how far they could walk, and asked the patients how they felt, both at the beginning and the end of their two weeks of daily baths. Only those who had soaked in the Dead Sea salts showed any improvement in their condition.

Applying physiology

It's worth noting, though, that replicating the conditions of the Dead Sea in a bathtub takes several pounds of salt. Patrick Barron, a naturopath who teaches hydrotherapy in Florida, scoffs at those spas that claim to help their clients' health by throwing a handful of bath salts into a whirlpool.

The healing power of hydrotherapy, he says, is based on how the body functions. For example, to treat a cold and flu, he recommends saunas and steam baths on the theory that perspiration can cleanse toxins from the body. The therapy may also be effective because, according to him, heat can stimulate the immune system, increasing the number of germ-fighting white blood cells.

But Barron is also quick to acknowledge that, benign as a bath may seem, hydrotherapy can actually be dangerous. Hot water can damage the feet of people who have diabetes and others with peripheral vascular disease. As with any medicine, he advises, check with your doctor before using it to treat an illness.