Q. What is hydrotherapy, and how can I benefit from it?

Hydrotherapy, broadly defined, is the therapeutic use of water. For centuries, cultures around the world have used water in various ways as a natural healing agent. Modern hydrotherapy typically consists of hot and/or cold water applied in showers, soaks, saunas, steam baths, compresses or wraps. Naturopathic physicians are trained to use water as a gentle means of helping the body to detoxify, decrease inflammation, increase or decrease blood flow, move lymph, soothe pain, decrease fevers and boost overall immunity.

You've probably heard about those crazy Scandinavians who sit in saunas, then jump through holes chopped in the ice to bathe in frigid water. They may not be as crazy as they seem; in fact, they are practicing an extreme form of what is known as "contrast hydrotherapy."

According to the Manual of Hydrotherapy and Massage by Dr. Fred Moore, et al., when hot water is applied to the skin there are significant increases in local blood flow, increased migration of immune-fighting cells, muscles in the local area are more relaxed, and there is local pain relief. With the application of cold water to the skin there is constriction of blood flow, fewer immune-fighting cells in the area affected, and decreases in local tissue metabolism and pain. When hot and cold water are applied correctly and alternated — hence the term "contrast" hydrotherapy — there can be tremendous therapeutic value.

I often recommend contrast hydrotherapy to help my patients increase their circulation and boost their immune systems. This is one of the many areas where Western and Eastern medicine concur: according to Chinese medicine, contrast hydrotherapy can stimulate your qi, or vital force, and strengthen your immunity.

You can experience the benefits of a simple form of contrast hydrotherapy every time you take a shower. Toward the end of a hot shower, switch the water to cold and let it run down your back, then your entire body, for 20 seconds. (You may want to start with five seconds and slowly work your way up to 20 seconds over several days.) The cold water may seem shocking at first, but if you do this frequently you will gradually come to enjoy the short-term stimulating effects: You might find that you no longer need that cup of java in the morning to wake up. You may also experience the longer-lasting relaxing effects and the sense of well-being that comes from boosting your immunity naturally.

Laurie Steelsmith is a naturopathic physician and licensed acupuncturist in Honolulu, as well as author of the book "Natural Choices for Women's Health," (Random House). You can reach her and read her past columns at www.DrSteelsmith.com. This column is for information only. Consult your health provider for medical advice.