title: Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.
abstract: [Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, China; Department of Rehabilitation Medicine, China-Japan Friendship Hospital, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, USA.
authors.forename: Christina Wan-Ying
authors.initials: CW
authors.lastname: Hui-Chan
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, China.
authors.forename: William Wai-Nam
authors.initials: WW
authors.lastname: Tsang
keywords: Heart rate variability; Prefrontal activity; Tai Chi