ABC | Volume 110, Nº2, February 2018

Original Article Amaral et al Autonomic and vascular control in prehypertensive patients Arq Bras Cardiol. 2018; 110(2):166-174 In addition to sensitivity, the response time of the baroreflex can also determine the efficiency of this reflex. 35 In this study, we verified the baroreflex response time preserved in prehypertensive patients. This characteristic of the baroreflex is mainly affected by changes in cardiac parasympathetic nervous modulation, 36 a change that was not observed in the prehypertensive patients evaluated in this study. Therefore, it is possible that the response time of the baroreflex could be affected later in the course of pressure rise and development of hypertension and that in the prehypertension phase only the reduction of the gain contributes to the reduction of the efficiency of this reflex. In addition, the fact that the volunteers in this study have FHSAHmay be related to the observed results. No studies were found to investigate this time delay of the baroreflex effector response in prehypertensive individuals, as well as in childrenwith hypertensive parents, which made difficult to compare our results. This study demonstrated that prehypertensive youngsters with FHSAH present autonomic dysfunction and vascular function similar to normotensive with the same risk factor. Thus, the results of this study emphasize the importance of preventive intervention with measures aimed at attenuating this dysfunction and, consequently, acting on the prevention of hypertension in this population. In this sense, physical exercise has been considered effective since it acts in a beneficial way in multiple physiological systems. 37 In addition, the benefits of regular aerobic physical exercise in the attenuation of autonomic dysfunction have already been demonstrated both in prehypertensive patients 37 and in the descendants of hypertensive parents, 38 which leads us to believe that individuals with both risk factors may also benefit from the effects of this practice. Limitations The diagnosis of SAH of the parents of the volunteers of this study was self-reported. Although self-report has been used in many studies, 38,39 future research should include detailed medical evaluation of the parents. The presence of renal diseases was not an exclusion criterion in this study, since all the necessary tests to exclude safely this characteristic were not performed. In spite of this, all the volunteers declared that they did not have a diagnosis of renal diseases and those who did the creatinine and uric acid tests presented normal values for these variables. Additionally, the women in this study were not evaluated during the same period of the menstrual cycle, a fact that may also be a limitation of this work. However, Jarvis et al. 40 and Carter et al. 41 observed no influence of the ovarian cycle phase on sympathetic modulation, heart rate and BP during rest in young women. Despite the limitations pointed out, the great strength of this study is the fact that we evaluated young adults, without medication and with similar glycemic and lipid profile. Conclusion We conclude that prehypertensive patients with FHSAH have autonomic dysfunction, characterized by increased peripheral sympathetic modulation and reduced baroreflex control of heart rate, and increased vascular conductance when compared to normotensive patients with the same risk factor. Author contributions Conception and design of the research and Critical revision of the manuscript for intellectual content: Amaral JF, Borsato DMA, Freitas IMG, Toschi-Dias E, Martinez DG, Laterza MC; Acquisition of data: Amaral JF, Borsato DMA, LaterzaMC; Analysis and interpretation of the data: Amaral JF, Borsato DMA, Freitas IMG, Toschi-Dias E, LaterzaMC; Statistical analysis and Writing of the manuscript: Amaral JF, LaterzaMC. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the thesis of Doctoral submitted by Josária Ferraz Amaral, from Universidade Federal de Juiz de Fora. Ethics approval and consent to participate This study was approved by the Ethics Committee of Universidade Federal de Juiz de Fora under the protocol number 720/370. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 172