IJCS | Volume 32, Nº1, January/ February 2019

49 Boeno et al. Post-exercise hypotension Int J Cardiovasc Sci. 2019;32(1)48-54 Original Article interval exercise (HIIE). 7 In fact, both aerobic and resistance exercises have similar effects on PEH, with slightly stronger effects of CONT. 8 Besides, interval exercise protocols have drawn attention from scientific community, as they promote an increase in peak oxygen consumption, insulin sensitivity and mitochondrial enzymes, at the same proportion as observed with traditional continuous exercises in sedentary subjects, although these types of exercises require five-fold higher exercise volume as compared with HIIE. 9 Regardless of the type of exercise, volume seems to be determinant for the magnitude of cardiovascular responses, influencing PEH. In this context, the effects of CONT and HIIE, adjusted for equivalent volumes, on hemodynamic variables are unknown. Therefore, the current study aims to investigate and compare PEH in response to HIIE and to CONT, matched by volume, in young sedentary individuals. Methods Subjects Thirteenmen aged 20-30 years, with sedentary lifestyle for at least six months 10 and no history of diseases, were recruited by convenience through print media and online social media. The following exclusion criteria were used: (1) individuals unable to exercise due to physical or psychological limitations; and (2) individuals using ergogenic aids or tobacco. The study was approved by the local ethics committee (approval number 2.202.349) and performed according to the Helsinki Declaration. Experimental design This randomized crossover study consisted of three days of evaluations separated by 72 hours. On day 1, measurements of blood pressure (BP), heart rate (HR) and body mass index (BMI) using a scale and a stadiometer were obtained, and ergometric test was performed to determine maximal heart rate (maxHR). On days 2 and 3, patients underwent two exercise sessions – HIIE or CON in a random sequence. The website www.randomizer.org was used for randomization of the experimental conditions. Hemodynamic measurements BP measurements were taken using a digital sphygmomanometer (Omron, HEM-907, Japan) previously validated. 11 Measures were taken with individuals in sitting position at rest. Resting BP was measured on the first day of evaluation, following the VII guidelines for hypertension of the Brazilian Society of Cardiology. 4 BPmeasurements were taken on exercise test days before, immediately after and every five minutes thereafter during a 60-min resting period. HR was measured using a heart rate monitor (Polar Electro Oy, V800, Finland) every time BP was taken. Double product (DP) was calculated by the formula DP = SBP x HR at predetermined time points. Ergometric test and peak oxygen consumption (peak VO 2 ) Maximal effort ergometric test was performed on a treadmill (Imbramed, ATL 10200, Brazil), following the Conconi protocol. 12 Initial velocitywas set at 5 km/h, with increments of 1 km/h/minute. The tests were interrupted when two of the following criteria were met – HR above that predicted for age (220-age), perceived exertion ≥ 20 on Borg’s scale 13 or voluntary exertion. Peak oxygen consumption was predicted using a formula previously validated for the Brazilian population. 14 All volunteers were verbally encouraged to reach maximal exertion during the tests. Exercise protocol Exercise protocols were conducted using a treadmill (Imbramed, ATL 10200, Brazil). The protocols were equalized by volume, or distance covered, i.e., in both protocols, the distance covered was 5 km. 15 Continuous aerobic exercise (CONT) After a 5-minute warm-up, treadmill velocity was adjusted to 70% of the maximal heart rate reached during the ergometric test. This velocity was maintained until the volunteers ran a total of 5 km. 15 High-intensity interval exercise (HIIE) After a 5-minute warm-up, the volunteers performed an intermittent 5-kmrunning test, consisting of a 1-minute running at 90% of maximal heart rate followed by a 1- minute resting period at 60% of maximal heart rate. 15 Statistical analysis Normality of data distribution was analyzed by the Shapiro-Wilk test. Two-way ANOVA (conditions