Tai Chi is a moderate cardiovascular training exercise, which also has a significant effect on lung function.
Tai Chi can beneficially alter the lipid profile, raising the possibility that practising Tai Chi might be favourable in the prevention of atherosclerosis.
Tai Chi is one of the few exercises that is appropriate for virtually any person regardless of their condition - it can even be done in a chair or bed. It has also been shown to improve the activities of daily living for people with rheumatoid arthritis, osteoarthritis, Parkinson's disease, multiple sclerosis - to name a few.
Tai Chi helps regulate the immune system.
Tai Chi helps postural alignment and helps reduce spinal degeneration.
Tai Chi is a weight bearing exercise, which raises the possibility of benefits for maintaining bone density.
Tai Chi is rated as a highly effective exercise for prevention of falls in the elderly.
Sounds like yoga! I do have an interest in tai chi but I was always especially fascinated with the martial arts version...the slower version that we know here in America is apparently the foundational poses you learn as the basis of what can be a kick-ass martial art. I don't know much about it though, so can't say more than that...