Tai Chi for Health Purposes
Tai chi is a mind-body practice that originated in China as a martial art. A person doing tai chi moves his body slowly and gently, while breathing deeply and meditating (tai chi is sometimes called "moving meditation"). Many practitioners believe that tai chi helps the flow throughout the body of a proposed vital energy called qi (pronounced "chee," it means "air" or "power").Among the different names and spellings of tai chi are taiji and t'ai chi. Many consider the term "tai chi" to be a shortened form of "tai chi chuan" (two other spellings are t'ai chi ch'uan and taijiquan).
A Description of Tai Chi
Tai chi developed in China in about the 12th century A.D. It started as a martial art, or a practice for fighting or self-defense, usually without weapons. Over time, people began to use tai chi for health purposes as well. Many different styles of tai chi, and variations of each style, developed. The term "tai chi" has been translated in various ways, such as "internal martial art," "supreme ultimate boxing," "boundless fist," and "balance of the opposing forces of nature." While accounts of tai chi's history often differ, the most consistently important figure is a Taoist monk (and semilegendary figure) in 12th-century China named Chang San-Feng (or Zan Sanfeng). Chang is said to have observed five animals—tiger, dragon, leopard, snake, and crane—and to have concluded that the snake and the crane, through their movements, were the ones most able to overcome strong, unyielding opponents. Chang developed an initial set of exercises that imitated the movements of animals. He also brought flexibility and suppleness in place of strength to the martial arts, as well as some key philosophical concepts.
A person practicing tai chi moves her body in a slow, relaxed, and graceful series of movements. One can practice on one's own or in a group. The movements make up what are called forms (or routines). Some movements are named for animals or birds, such as "White Crane Spreads Its Wings." The simplest style of tai chi uses 13 movements; more complex styles can have dozens.
In tai chi, each movement flows into the next. The entire body is always in motion, with the movements performed gently and at uniform speed. It is considered important to keep the body upright, especially the upper body-many tai chi practitioners use the image of a string that goes from the top of the head into the heavens-and to let the body's weight sink to the soles of the feet.
In addition to movement, two other important elements in tai chi are breathing and meditation. In tai chi practice, it is considered important to concentrate; put aside distracting thoughts; and breathe in a deep, relaxed, and focused manner. Practitioners believe that this breathing and meditation have many benefits, such as:
    Massaging the internal organs.
    Aiding the exchange of gases in the lungs.
    Helping the digestive system work better.
    Increasing calmness and awareness.
    Improving balance.

Other Key Beliefs in Tai Chi
Certain concepts from Chinese philosophy were important in tai chi's development (although not every person who practices tai chi for health purposes, especially in the West, learns or uses them). A few are as follows:
    A vital energy called qi underlies all living things.
    Qi flows in people through specific channels called meridians.
    Qi is important in health and disease.
    Tai chi is a practice that supports, unblocks, and redirects the flow of qi.
Another concept in tai chi is that the forces of yin and yang should be in balance. In Chinese philosophy, yin and yang are two principles or elements that make up the universe and everything in it and that also oppose each other. Yin is believed to have the qualities of water—such as coolness, darkness, stillness, and inward and downward directions—and to be feminine in character. Yang is believed to have the qualities of fire—such as heat, light, action, and upward and outward movement—and to be masculine. In this belief system, people's yin and yang need to be in balance in order for them to be healthy, and tai chi is a practice that supports this balance.
Specific Health Purposes
People practice tai chi for various health purposes, such as:
    For benefits from exercise:
    Tai chi is a low-impact form of exercise.
    It is a weight-bearing exercise that can have certain health benefits—for example, to the bones.
    It is an aerobic* exercise.
    To improve physical condition, muscle strength, coordination, and flexibility.
    To have better balance and a lower risk for falls, especially in elderly people.
    To ease pain and stiffness—for example, from arthritis.
    For health benefits that may be experienced from meditation.
    To improve sleep.
    For overall wellness.
* Aerobic exercise has benefits to the heart and possibly to cholesterol levels. This type of exercise causes the heart to work harder to pump blood more quickly and forcefully. The body adds oxygen to the blood faster, and the person breathes more quickly. Two other examples of aerobic exercise are swimming and brisk walking.
Side Effects and Risks
Tai chi is a relatively safe practice. However, there are some cautions.
    Tell your health care provider if you are considering learning tai chi for health purposes (especially if you have a health condition for which you are being treated, if you have not exercised in a while, or if you are an older person).
    If you do not position your body properly in tai chi or if you overdo practice, you may get sore muscles or sprains.
    Tai chi instructors often recommend that people not practice tai chi right after they eat, or when they are very tired, or when they have an active infection.
    Use caution if you have any of the conditions listed below, as your health care provider should advise you whether to modify or avoid certain postures in tai chi:
    Pregnancy
    Hernia
    Joint problems, back pain, sprains, a fracture, or severe osteoporosis

Source – NCCAM (National center for complimentary and alternative medicine.