Master Yon G. Lee leads his class through an exercise, his sweeping arm and hand motions and gliding steps guiding the rest of the group. The motions, graceful and light, make the musky room at the Malkin Athletic Center (MAC) seem like the stage for a slow-motion modern dance.

Lee says many of his students come to the Tai Chi class for a relaxing break from work. The slow movement calms them after a stressful day.

"I would say about 80 percent of people come here for balance, to get away from stress," says Lee. " It keeps them focused."

Tai Chi, which has been practiced for over 2,000 years, is one of the original systems of martial arts. Thousands of Chinese, who believe that Tai Chi preserves health and prevents aging, still use it as their daily exercise.

For most people, Tai Chi is an exercise that helps them focus and manage stress--which is now reaching its annual peak at Harvard, with the holiday season and exam period right around the corner.

"You stop thinking about anything else. It helps me concentrate, makes me feel balanced," says Sae Takada '03.

Most of the students, like Takada, are beginners who have been testing the soothing effects of Tai Chi since the semester began.

"I wasn't really into anything athletic," says Takada, "But I wanted to do something that was relaxing and had some martial arts significance to it."

Tai Chi is "so multi-level" that it can serve different people's needs, Lee says. "It's a very natural process. It develops your inner strength, balance, and most importantly, inner peace."

And the most remarkable thing about Tai Chi, according to Lee, is that it only takes a few minutes a day.

Tai Chi exercise sequences are cumulative, so they can be broken up into short segments and performed easily during any point in the day.

"This gives you a cardiovascular workout without going through the sweating of aerobics," Lee says.

For Takada, it is precisely this flexibility that lets her enjoy Tai Chi.

Takada, a pianist, often experiences stiffness in her shoulder. She says that basic Tai Chi exercises--specifically the "double cranes in flight" and the "separation of heaven from earth"--help her alleviate the discomfort.

"It's just five minutes, and it does wonders," she says. "I do it every morning now."

But Tai Chi may do more than help with stiff shoulders. Recently, the medical community has begun looking at Tai Chi more closely.

Lee says that he is currently working with researchers at the Harvard Medical School to see if Tai Chi can be used can be used as physical therapy for people with diabetes, osteoporosis or arthritis.

Lee encourages anyone interested in Tai Chi to "just show up" at any of his classes, which are held Tuesdays and Thursdays at noon and 5:30 at the MAC.

Yoga is another exercise alternative offered at the MAC that is said to help relieve stress. Sessions last from one to two hours and are taught five days a week by two different instructors.

Stephanie L. Hunter, a third-year at Harvard Law School, began taking yoga at the MAC this semester and says it is yoga an easy way to relieve stress.

"It's wonderful. By the time you've stretched for an hour, you're completely relaxed," Hunter says.

There are many different ways to teach yoga, and Hunter says the classes at the MAC are more focused on exercise than other programs.

"It's predominantly stretching but by the time you've stretched, you get the heart rate up," she says.

Other approaches to yoga emphasize its spiritual and mental aspects.

Students can also take yoga at Bodyworks Cambridge, where director Ayn Rose has been teaching yoga for over 20 years with an approach that she says will bring out the vitality in her students.

"To me, yoga is the union of the body and the mind," says Rose, adding that she teaches yoga not so much as a form of exercise but to allow a person "to become more focused and relaxed, and to have more energy."

Bodyworks also offers massage sessions. It is located at 329 Broadway in Cambridge. To sign up for a class, call 868-3777.