One of the problems about getting older is that the activity of the sympathetic nervous system may increase, bringing with it an increased risk of metabolic problems such as insulin resistance, hypertension and cardiovascular disease.
The sympathetic nervous system is a branch of the autonomic nervous system. It is always active at a basal level, which is called sympathetic tone. It becomes more active during times of stress. Its actions during the stress response comprise the classical fight-or-flight response.
There is a very interesting study from the Norman Cousins Center for Psychoneuroimmunology at the UCLA Semel Institute for Neuroscience & Human Behavior in Los Angeles.
There were 32 people in the study aged 60 or over. There were 19 people who were T’ai Chi Chih (TCC) practitioners and 13 who were not. The practitioners had completed a 25-week training in TCC the 13 others just had health education classes. T'ai Chi Chih is a simplified type of T'ai Chi that emphasizes the development of qi, a.k.a. chi.
TCC practitioners performed the breathing and movements for 20 minutes, while HE participants passively rested for the same time. Investigators measured various cardiovascular parameters before and after the task. A subsample of participants returned for a second evaluation and performed videotape-guided stretching for 20 minutes to evaluate the cardiovascular effects of slow-moving physical activity. TCC performance was found to significantly decrease sympathetic nervous system activity as measured by cardiac pre-ejection, blood pressure and heart rate. In contrast, there was no change in sympathetic activity following passive rest or slow-moving physical activity.
This shows us that there is something different about T’ai Chi. Practicing it leads to a decrease in activity of the sympathetic nervous system to levels that are not achieved by performing comparable physical activity alone.