ABC | Volume 115, Nº1, July 2020

Original Article Vargas & Rigatto Parents’ BP and young men autonomic impairment Arq Bras Cardiol. 2020; 115(1):52-58 equipped with a 7- 12-MHz high-resolution linear probe (L12-3, GE Medical Systems, Israel). The ultrasonography was performed in a silent, temperature-controlled room. At rest, the left brachial artery diameter was measured by B-mode ultrasound images to detect reactive hyperemia. Before BP cuff inflation, a resting scan was performed. After the resting measurement, the cuff was inflated for 5 min at 50 mmHg above SBP, to occlude the arterial flow. This procedure causes ischemia followed by vasodilation due to auto-regulatory mechanisms. After the cuff deflation, a second continuous scan was recorded from 30–120 seconds. The same experienced sonographer performed and analyzed all ultrasound scans without knowing the genetic history of each athlete. At a fixed position, the vessel diameter was measured offline with ultrasonic calipers at end-diastole, and coincident with the R wave on an electrocardiogram, which was continuously recording. After an interval of 10 seconds and during the period within 30–180 seconds, the dilatation was obtained by the difference from baseline. After the release of the sphygmomanometer cuff, the flow-mediated dilation (FMD, %) indicates the increase in blood flow. 14 Maximal oxygen uptake The Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) was used to infer the VO 2max . The athletes performed 2×20-minute shuttle runs at increasing speeds, interspersed with a 10-second period of active recovery. The test was controlled by audio signals from a compact-disc player and ended when the athlete was unable to maintain the speed for the test. The distance traveled at that point was the result of the test, as described by Bangsbo et al. 15 The indirect measurement of VO2max was calculated as follows: VO 2max (ml/min/kg) = IR1 distance (meters) × 0.0084 + 36.4 14 Statistical analysis All analyses were performed with the SPSS software version 10.0 (SPSS Inc., Chicago, IL). The data normality and equality were assessed through the Shapiro–Wilk and Levene’s tests. The results of parametric data are presented as mean ± standard deviation, and the results of non-parametric data are described as median and interquartile range. In the inferential statistical analysis, one-way ANOVA was used to compare the groups, followed by Tukey’s post hoc test, when parametric data. The Kruskal-Wallis test was used to compare the groups when non-parametric data, and U of the Mann-Whitney test was used to verify the differences between the groups. A significance level of 0.05 was adopted for all the tests. To detect a minimum 30% difference between the groups with a minimum probability of a type I error of 5% ( α = 0.05) and a probability of type II error of 20% ( β = 0.2), the minimum number of individuals for each group was estimated at 10, based on a preliminary study. 11 Results Anthropometric, SBP, DBP, maximal oxygen uptake measurements and parents’ BP There was no significant difference among groups regarding the age (years; 17.65±0.7), weight (kg; 69.25±3.6), and height (cm; 175.2±5.7). Moreover, VO 2max (ml/min/kg) indicated that physical fitness was similar among groups, and SBP and DBP (mmHg) were not different among the groups either (Table 1). According to the definitions and classification of office blood pressure levels, 3 the blood pressure level in 15.3% (n = 7) of the athletes was optimal BP (BP<120 and 80mmHg), 39.1% (n = 18) of them presented normal BP (BP = 120-129 and/or 80-84mmHg), and 45.6% (n = 21) had high normal blood pressure (BP = 130-139 and/ or 85-89 mmHg). SBP: systolic blood pressure; DBP: diastolic blood pressure; VO 2max : maximal oxygen uptake. Blood pressure values are expressed as mean (confidence interval) and VO 2max values, as mean ± SD. The parents’ BP are shown in Table 2. The parents’ systolic and diastolic blood pressures were higher in the hypertensive group when compared to the normotensive one. Heart rate and time-domain and frequency-domain measurements of resting heart-rate variability In our study, the HRV in the time domain was significantly lower in the FM-H than in the FM-N group (Table 3). The spectral analysis, using a frequency-domain method (HFnu) was significantly lower in the FM-H than in the FM-N group, and LFnu and the LF/HF ratio were significantly higher in the FM-H than in the FM-N group (Figure 1). Endothelial function assessment There was no significant difference between the groups regarding FMD or baseline brachial artery diameter upon reactive hyperemia, either before or after nitroglycerin- mediated vasodilatation (Table 4; P>0.05). Table 1 – Measurements of systolic and diastolic blood pressure and maximal oxygen uptake FM-N (n=14) F-H (n=11) M-H (n=10) FM-H (n=11) SBP (mmHg) 124 (117-132) 128 (114-134) 128 (111-139) 128 (120-139) DBP (mmHg) 72 (60-84) 76 (65-83) 79 (67-89) 78 (60-89) VO2max (ml/kg/min) 53.5±2.5 52.3±2.9 53.4±1.1 51.4±1.6 SBP: systolic blood pressure; DBP: diastolic blood pressure; VO 2max : maximal oxygen uptake. Blood pressure values are expressed as mean (confidence interval) and VO 2max values, as mean ± SD. 54