Função vascular e autonômica cardíaca de filhos de hipertensos fisicamente ativos em repouso e durante o exercício físico

Abstract

INTRODUCTION: Offspring of hypertensive parents have vascular and autonomic dysfunction at rest and during exercise. However, it is known that exercise training can reverse those changes, but in hypertensive individuals. Thus, the objective of this study was to test the hypothesis that regular physical exercise improves vascular and autonomic function of offspring of hypertensive at baseline conditions and during exercise. METHODS: We evaluated 13 offspring of hypertensive physically active (FHA) and 22 offspring of hypertensive sedentary (FHS), matched for age (22.5 ± 2.9 vs. 23.8 ± 2.7, p=0.18) and BMI (23.8 ± 1.9 vs. 23.0 ± 3.0, p=0.45). For 10 minutes was collected continuously the heart rate signal, by the heart rate monitor Polar RS800CX. Then, blood pressure was measured by the auscultatory method. Subsequently, the isometric exercise protocol handgrip at 30% maximal voluntary contraction was performed, and recorded simultaneously blood pressure, minute by minute (oscillometric method - DIXTAL 2022), forearm blood flow (occlusion plethysmography venous - Hokanson) and heart rate (heart rate monitor - Polar RS800CX) continuously for 3 minutes baseline and three minutes of exercise. The heart rate signal was used for analysis of cardiac autonomic modulation by the heart rate variability method at baseline and during exercise protocol. The forearm vascular conductance was calculated by dividing the forearm blood flow by the mean arterial pressure and multiplied by 100. The Student t-test, U de Mann-Whitney and two-way ANOVA were used, a significance p≤0,05. RESULTS: At baseline, the groups were similar for systolic blood pressure, diastolic and mean (p=0.42, p=0.94 and p=0.71, respectively) and forearm blood flow (p=0.06). But the FHA group showed the lowest resting heart rate (p<0.01) and increased vascular conductance of the forearm (p=0.05). In the analysis of cardiac autonomic modulation at rest were observed significantly higher values of the variables MNN (p<0.01), RMSSD (p=0.01), pNN50 (p=0.01) and HF (p=0.02) in the FHA group. During the exercise, the FHA group showed responses significantly higher of heart rate, systolic blood pressure, diastolic and mean (p<0.01, p<0.01 and p<0.01, respectively). Confirming our hypothesis, the FHA group had higher responses in the 2nd and 3rd minute of exercise for the forearm blood flow (p<0.01 and p<0.01, respectively) and vascular conductance of the forearm (p<0.01 and p=0.03, respectively). Furthermore, the measures MNN (p=0.05), SDNN (p=0.02), RMSSD (p=0.02) pNN50 (p=0.03) and LF (p=0.02) were higher in FHA group during exercise protocol. CONCLUSION: We conclude, therefore, that offspring of hypertensive physically active have better vascular function and cardiac autonomic modulation at baseline conditions and during exercise.