Tai Chi Chih acutely decreases sympathetic nervous system activity in older adults Author: Motivala, S., Sollers, J., Thayer, J. & Irwin, M. Conference/Journal: Journal of Gerontology a Biological Science Medicine Date published: 2006 Other: Volume ID: 61 , Issue ID: 1177-1180 , Word Count: 42 Aging is associated with increases of sympathetic nervous system activation implicated in the onset of hypertension and cardiovascular disease. TCC practitioners performed TCC for 20 minutes, and TCC-naïve participants passively rested. TCC performance significantly decreased sympathetic activity as indexed by preejection period