Done in a series, yoga positions tone muscles and increase flexibility, while proper breathing brings calm and concentration. 

Yoga is widely recognized to benefit the brain as well as the body. Denise Rowe, a 38-year-old lawyer in Washington, D.C., was a self-described workaholic before taking up yoga. "It has allowed me to become more centered, focused and relaxed," says Rowe. 

And because stress is known to harm the body, relaxing can be lifesaving. Yoga, combined with a low-fat diet and moderate aerobic exercise, can significantly reduce blockages in coronary arteries, reports the Preventive Medicine Research Institute in Sausalito, Calif. "We found a strong correlation between the amount of yoga practice and opening up of the arteries," says Larry Scherwitz, research director of the institute. Funded by the National Institutes of Health, the study was published in the Journal of the American Medical Association.

Other studies have shown yoga to be effective in treating arthritis, diabetes, mood disorders, asthma, high blood pressure and menstrual cramps. 

Many people use yoga's meditative nature as a path to spiritual growth. "Getting your body in a certain state of fitness and relaxation is a launching point for focusing your attention on meaning-of-life questions," says Gajevski, of the American Yoga Association. "Unfortunately, some people confuse yoga with a conflict with religion. But it can actually enhance religion. 

"Yoga makes you more of what you are."