Racial Differences in Blood Pressure Variability, Baroreflex Sensitivity and Heart Rate Variability Following Maximal Exercise

Abstract

IntroductionHeart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS), measures of autonomic nervous system function, are associated with cardiovascular (CV) outcome. African Americans (AA) have an increased prevalence of CV disorders in comparison to Caucasians (C).PurposeTo determine race specific responses in BPV, BRS and HRV before and after maximal exercise.Methods37 AA and 37 C (24 years) underwent maximal exercise on a cycle ergometer. BPV, BRS and HRV measurements were assessed using finger plethysmography before and after exercise. Data were log transformed and pre‐and post‐max test values were compared by race.ResultsAcute exercise significantly decreased BRS, LF‐HRV and HF‐HRV and significantly increased LF/HF‐HRV in both AA and C. With exercise, C significantly decreased measures of BRS and HRV more compared to AA; BRS‐SAPRRI transfer mean (C: 2.65±.54 to 1.09±.81 versus AA: 2.70±.40 to 1.70±.92), BRS‐down down (C: 3.21±.55 to 1.74±.49 versus AA: 3.28±1.0 to 2.2±.71), HRV‐LF (C: 6.39±.86 to 3.68±1.42 versus AA: 6.37±1.24 to 5.18±2.14) and HRV‐HF (C: 7.38±1.23 to 3.53±1.73 versus AA: 7.51±1.09 to 5.38±2.16).ConclusionC exhibited increased vagal withdrawal and greater reductions in BRS compared to AA in response to acute exercise. The impact of these racial differences in autonomic control on CV risk needs further investigation.