title: Tai Chi Chih acutely decreases sympathetic nervous system activity in older adults.
abstract: BACKGROUND
  Aging is associated with increases of sympathetic nervous system activation implicated in the onset of hypertension and cardiovascular disease. The purpose of this study was to examine whether the practice of Tai Chi Chih (TCC), a movement-based relaxation practice, would acutely promote decreases of sympathetic activity in elderly persons.
  
  
  METHODS
  The sample included two groups of older men and women (age > or = 60 years): TCC practitioners (n = 19) and TCC-naïve participants (n = 13). Participants were recruited after completing a 25-week randomized trial of TCC or health education. TCC practitioners performed TCC for 20 minutes, and TCC-naïve participants passively rested. Preejection period, blood pressure, and heart rate were measured before and after the task. A subsample (n = 8) returned for a second evaluation and performed videotape-guided stretching for 20 minutes to evaluate the effects of slow-moving physical activity on sympathetic activity.
  
  
  RESULTS
  Results showed that TCC performance significantly decreased sympathetic activity as indexed by preejection period (p =.01). In contrast, there was no change in preejection period following passive rest or slow-moving physical activity. Neither blood pressure nor heart rate changed after TCC performance.
  
  
  CONCLUSIONS
  This study is the first to our knowledge to assess the acute effects of TCC practice on sympathetic activity in older adults. TCC performance led to acute decreases in sympathetic activity, which could not be explained by physical activity alone. Further study is needed to determine whether the acute salutary effects of TCC on autonomic functioning are sustained with ongoing practice in older adults.
authors.affiliation: Cousins Center for Psychoneuroimmunology, UCLA Semel Institute for Neuroscience & Human Behavior, 300 Medical Plaza, Suite 3148, Los Angeles, California 90095-7057, USA. smotivala@mednet.ucla.edu
authors.forename: Sarosh J
authors.initials: SJ
authors.lastname: Motivala
authors.forename: John
authors.initials: J
authors.lastname: Sollers
authors.forename: Julian
authors.initials: J
authors.lastname: Thayer
authors.forename: Michael R
authors.initials: MR
authors.lastname: Irwin
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D002307:Cardiography, Impedance; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013564:Sympathetic Nervous System / Q000502:physiology*; D026302:Tai Ji