Many medical research studies in the last 20 years have already shown that there are many health benefits from practicing Taiji.  These include benefits for lowering of blood pressure, increase in immunity to shingles, relief to osteoarthritis, improvement in the control of Type 2 diabetes, lowering stress and pain reduction, reducing probability of falling for senior citizens, reducing probability of Alzheimer’s disease, and general improvement in overall health. A recent study  shows an additional benefit from practicing Taiji with respect to Parkinson’s disease.
Parkinson’s disease is a degenerative disorder of the central nervous system. It belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. Dopamine is a chemical released by nerve cells to send signals to other nerve cells. The four primary symptoms of Parkinson’s disease are (1) tremor, or trembling in hands, arms, legs, jaw, and face; (2) rigidity, or stiffness of the limbs and trunk; (3) bradykinesia, or slowness of movement; and (4) postural instability, or impaired balance and coordination. As these symptoms become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. At advanced stages, cognitive and behavioural problems and dementia may arise.
This recent study conducted a randomized, controlled trial of 195 patients with stage 1 to 4 affliction with Parkinson’s disease.  These 195 patients were randomly assigned to one of three groups: Taiji, resistance training, or stretching. The patients participated in 60-minute exercise sessions twice weekly for 24 weeks. At the end of 24 weeks, they were given several Parkinson’s disease-related standardized tests to measure various parameters related to strength, movement control, balance, stride length and reach, and number of falls.
The Taiji group performed consistently better than the stretching group in all the above measurements of strength, movement control, balance, stride length and reach, and number of falls. The Taiji group also outperformed the resistance-training group in the measurements of strength, movement control, balance, stride length and reach, and about the same in the number of falls. Furthermore, the benefits of Taiji training were maintained at three months after the 6-month study, and no serious adverse effects were observed. The improvements were statistically significant.
These research findings show that the quality of life of Parkinson disease patients can be improved, because people with Parkinson disease often lose the ability to maintain standing balance and have difficulty walking and are at risk for frequent falls. Furthermore, current medications do not work well to relieve impaired balance or postural instability, besides having negative side effects, although medications can relieve some symptoms of Parkinson’s disease like tremors.
This study did not offer any explanation on why Taiji can have these positive impacts on Parkinson’s disease. The cause of Parkinson’s disease is due to insufficient dopamine-generating cells in the midbrain, and the cause of this loss is not known. Although we do not know how and if practicing Taiji can overcome this chemical problem, we do know that practicing Taiji can give rise to physiological results that can enhance bodily motions. For example, we know that Taiji exercises and many of the warm-up exercises for Taiji classes can increase the strength and flexibility of the legs, thus increasing the reach and control of the legs and also reducing the probability of falls. The emphasis in Taiji on waist rotation can increase bodily flexibility and reach. Taiji movements emphasize proper placements of the feet (e.g., there should be one shoulder-width separation in the transverse direction between the left leg and the right leg, thus increasing the stability and balance. Taiji’s emphasis on relaxing the whole body can reduce stress and allow the muscles to function efficiently and with increased strength. Finally, the overall improvement of health from practicing Taiji should also result in some positive implications in various tests of strength, range and flexibility of motion. Therefore, even though currently we do not know if practicing Taiji can reduce the loss of dopamine-generating cells or perhaps even increase the regeneration of such cells, we do understand that some of the physiological benefits from practicing Taiji could improve the results of tests to measure Parkinson’s disease.
This recent study and many of the other studies during the last 20 years usually involved only a few dozen to a few hundred people. These studies must be repeated by many other groups and involving an order or two orders of magnitude larger. Personally, I believe that 20-30 years from now, we will have a strong confirmation of these indications of the positive health benefits of Taiji, and more importantly we will have a better understanding and explanation on why Taiji can lead to these health benefits.
 Taiji is also written as Tai Chi. For reviews of the health benefits of Taiji, see “Health Benefits of Taiji” and “A Comprehensive Review of Health Benefits of Qigong and Tai Chi“.
 Fuzhong Li, Ph.D., Peter Harmer, Ph.D., M.P.H., Kathleen Fitzgerald, M.D., Elizabeth Eckstrom, M.D., M.P.H., Ronald Stock, M.D., Johnny Galver, P.T., Gianni Maddalozzo, Ph.D., and Sara S. Batya, M.D. N Engl J Med 2012; 366:511-519, February 9, 2012. See “Tai Chi Benefits Patients with Parkinson’s“.
 Out of five stages. The higher the stage the more serious is the problem.