Tai Chi and QiGong work on the Qi flow along the channels that associate with our internal organs. They can offer theraputic effects if practiced correctly. Many examples in history proved that Tai Chi and QiGong effectively helped the weak to become strong and the sick to heal. It is a proven effective tool leading to a healthy and quality life.
Grandmaster WU Tunan (吴图南) lived 104 years (1885-1989). He was a sick boy when he was yong. His parents sent him to learn Tai Chi when he was nine years old. Later he taught marshall arts at schools and universities and became a well-known researcher in this field. One of his research subjects was longevity through Tai Chi and QiGong. He shared his experience at his 100-year birthday celebration. He said that he lived a full and quality life because of Tai Chi.
Please check out this link-- http://www.youtube.com/watch?v=0QRj4aqLsu8