IJCS | Volume 32, Nº1, January/ February 2019

50 Table 1 - Characteristics of the study group and exercise conditions Variables Mean ± standard deviation Age (years) 22.7 ± 2.6 BMI (kg/m²) 25.3 ± 2.7 Peak VO 2 (mL/kg/min) 35 ± 1.4 Resting SBP (mmHg) 125.7 ± 7.8 Resting DBP (mmHg) 80 ± 9.2 Resting heart rate (bpm) 69.6 ± 5.6 Maximal heart rate (bpm) 192.7 ± 6.3 HIIE CONT Pre SBP (mmHg) 127.9 ± 7.5 124.9 ± 7.2 Post SBP (mmHg) 141.8 ± 6.1 142 ± 8.1 Pre DBP (mmHg) 81.3 ± 7.4 82.7 ± 8.7 Post DBP (mmHg) 72.9 ± 6.8 78.8 ± 10.1 Minimum SBP (mmHg) 110 ± 6.7 111.5 ± 8 Minimum DBP (mmHg) 72.1 ± 10 73.5 ± 9.6 Pre-exercise heart rate (bpm) 84± 9.7 88.7 ± 12.3 Post-exercise heart rate (bpm)* 160.2 ± 17.7 139.2 ± 13.7 Session duration (min) # 35.4 ± 4.2 44.2 ± 2.1 BMI: body mass index; peakVO 2 : peak oxygen consumption; SBP: systolic blood pressure; DBP: diastolic blood pressure; CONT: continuous aerobic exercise; HIIE: high-intensity interval exercise; *: p = 0.02 between the groups; #: p = 0.04 between the groups. Boeno et al. Post-exercise hypotension Int J Cardiovasc Sci. 2019;32(1)48-54 Original Article vs. time points) test for repeated measures was used for within-group and between-group comparisons, followed by post-hoc Bonferroni test as appropriate. A p < 0.05 was set as statistically significant. All data were analyzed using the Statistical Package for Social Sciences (SPSS) 20 software. Data were expressed as mean ± standard deviation. Results Characteristics of the sample are described in Table 1. No significant differences were found in SAP, DAP, mean arterial pressure (MAP) or HR between the exercise protocols at the pre-exercise moment. Higher HR was found in HIIE immediately after exercise as compared with CONT (p = 0.02). Exercise duration was shorter for HIIE compared with CONT (p = 0.04). Other descriptive variables of each experimental condition are described in Table 1. Both conditions caused significant PEH. A significant reduction in SAP (p = 0.01) and MAP (p < 0.01) was observed at the 15 th minute after HIIE, persisting until one hour thereafter. A significant reduction in SAP (p = 0.04) and MAP (p = 0.01) was observed at the 35 th and 30 th minute, respectively, after CONT, and hence the beneficial effect of PEH occurred later after CONT than HIIE. No significant changes in DAP were found during the exercise tests. Also, no significant differences were found between SAP, MAP and DAP between the conditions. Changes in BP in response to different exercise protocols are shown in Figure 1. No differences were found in DP over the study period, except for the time immediately after the exercise, in which DP was higher in HIIE than in CONT (p = 0.03) (Figure 2). Discussion In the present study, we evaluated blood pressure behavior after two exercise conditions, matched by volume – CONT and HIIE. The main findings were: 1) both conditions promoted PEH; 2) HIIE promoted PEH at the 15th minute and thereafter, while the onset of PEH occurred only at the 30th minute following CONT. PEH has been systematically investigated, showing important effects on prevention and treatment of SAH. 5,7,8,16 The sum of the acute hypotensive effects in response to each exercise protocol promotes a long-term, protective effect on cardiovascular system, attenuating the risk for negative outcomes. 17,18 Therefore, manipulation of the type, volume and intensity of exercise is important for the selection of efficient and clinically applicable strategies. Previous studies have suggested that the effects of HIIE on PEHwere slightly superior than CONT. Angadi et al., 7 have shown that PEH occurs in both exercise conditions (HIIE and CONT, not matched by volume) during the first post-exercise hour in normotensive subjects. Nevertheless, PEHpersisted for three hours after HIIE. 7 In the study by Dantas et al., 19 HIIE significantly reduced ambulatory BP in normotensive individuals. This effect persisted for 5 hours after the session, and no changes were found in asleep BP. Nevertheless, the study 19 did not include an aerobic condition, whichmade it impossible to compare both conditions. Carvalho et al., 20 reported a significant PEH after HIIE and CONT