Are there any health benefits from tai chi exercises?

Tai chi, the slow, graceful Chinese exercise program that is sometimes called a "moving meditation," was originally created centuries ago as a martial art. It does appear to have some health benefits, though rigorous studies are hard to come by.

The National Center for Complementary and Alternative Medicine, an arm of the National Institutes of Health (nccam.nih.gov) notes, "It is not fully known what changes occur in the body during tai chi, whether they influence health, and if so, how." But so many Americans now practice the slow-moving exercise - 1.3 percent, according to a 2002 survey - that the government is now funding a number of studies to see what health benefits tai chi may hold.

Among the best-documented health effects for tai chi is its ability to improve balance, said biologist Peter Wayne, director of Tai Chi Research Programs from Harvard Medical School's Division for Research and Education in Complementary and Integrative Medical Therapies. In a systematic review of the published literature, Wayne and his colleagues found that 20 of 24 studies support the hypothesis that tai chi improves balance.

A recent study in the Journal of the American Geriatric Society found that tai chi can also boost immunity and protect older adults against shingles, a painful disease caused by reactivation of the chicken pox virus, which can linger in the body for decades. In this study, 112 adults age 59 to 86 were randomly assigned to tai chi or health education classes for 16 weeks.

Those who got tai chi had nearly twice as much immunity against the chicken pox virus (all participants had had chicken pox) measured by a blood test, as well as a stronger immune response to the chicken pox vaccine.

Tai chi has also been shown in a number of studies to lower blood pressure in people with hypertension.

But whether tai chi is any better for health than some other mind-body practices such as yoga and meditation remains to be seen, said Wayne. Tai chi teachers are not licensed by state boards, so a word of caution: If you are new to tai chi, check out several teachers and pick one with the most experience.

JUDY FOREMAN

E-mail health questions to foreman@globe.com.