Cardiac Autonomic Nervous Activities and Cardiorespiratory Fitness in Older Men

摘要: Background. Aging associated changes in sympatho-vagal activities have been widely studied. However, little is known about the association between cardiorespiratory fitness level and cardiac autonomic nervous conjunction with baroreflex sensitivity healthy older men. Methods. We performed an incremental submaximal exercise test 24 healthy, men aged 60-70 years. They were divided into physically fit (PF, oxygen uptake at anaerobic threshold [ATVO 2 ] = 25.2 ′ 0.85 ml.kg - 1 .min ) unfit (PU, ATVO 19.6 0.42 groups, based upon results of stress test. The system (ANS) assessed by means power spectral analysis heart rate variability. Baroreflex (BRS) testing was using simultaneous beat-by-beat blood pressure measurement during a transition from supine horizontal position to 60° head-up-tilting (HUT). Results. At rest conditions, high-frequency component (p =.03) total ( p =.04) variability spectrum significantly higher PF group. BRS passive HUT also (7.5 0.5 vs 3.0 0.4 ms.mm Hg , =.001) compared PU In addition, significant correlation coefficient (r =.73, found among subjects. Conclusions. maintenance high function, i.e., through life-long active lifestyle including endurance exercise, may play important role reserving ANS