Renata Aparecida Elias Dantas

ACUTE CARDIOVASCULAR RESPONSE TO PRE-PRANDIAL AND POSTPRANDIAL EXERCISE IN ACTIVE MEN

Introduction: pre-prandial exercise promotes greater mobilization of fat metabolism due to the increased release of catecholamines, cortisol, and glucagon. However, this response affects how the cardiovascular system responds to exercise. Objective: to evaluate the response of systolic, diastolic, and mean blood pressure, heart rate (HR) and rate-pressure product (RPP) to pre- and postprandial exercise. Methods: ten physically active male subjects (25.50 ± 2.22 years) underwent two treadmill protocols (pre- and postprandial) performed for 36 minutes at 65% of VO2max on different days. On both days, subjects attended the laboratory on a 10-hour fasting state. For the postprandial session, volunteers ingested a pre-exercise meal of 349.17 kcal containing 59.3 g of carbohydrates (76.73%), 9.97 g of protein (12.90%), and 8.01 g of lipids (10.37%). Blood pressure, HR and RPP were measured before and after exercise. The 2x2 factorial Anova with the multiple comparisons test of Bonferroni was applied to analyze cardiovascular variables in both moments (pre- vs. postprandial). The significance level was set at p<0.05. Results: systolic (121.70 ± 7.80 vs. 139.78 ± 12.91 mmHg) and diastolic blood pressure (66.40 ± 9.81 vs. 80.22 ± 8.68 mmHg) increased significantly after exercise only in the postprandial session (p<0.05). HR increased significantly (p<0.05) after both protocols (64.20 ± 15.87 vs. 141.20 ± 10.33 bpm pre-prandial and 63.60 ± 8.82 vs. 139.20 ± 10.82 bpm postprandial). RPP had a similar result (8052.10 ± 1790.68 vs. 18382.60 ± 2341.66 mmHg.bpm in the pre-prandial session and 7772.60 ± 1413.76 vs. 19564.60 ± 3128.99 mmHg.bpm in the postprandial session). Conclusion: these data suggest that fasted exercise does not significantly alter the blood pressure. Furthermore, the meal provided before the postprandial exercise may promote a greater blood pressure responsiveness during exercise.

Assessment of Bus Rapid Transit (BRT) Time Lags under Probabilistic Uncertainties

Large cities face growing mobility problems, due to the major traffic jams that result from high numbers of vehicles on the roads. In response, city and national governments have invested in alternative means of urban passenger transit, such as subways, trains, as well as Bus Rapid Transit (BRT). This article aims to analyze the BRT system, by attempting to calculate the probability of reaching a destination at a specific time, thereby providing a tool that can be employed to improve the system and increase passenger confidence in it. To this end, a Continuous Time Markov Chain (CTMC) model is proposed to represent the bus stations and compute the probability metric for arrival at the destination within the specified time frame. The model allows a mathematical function to calculate the probabilities for the corresponding architecture. Two case studies were conducted in order to verify the model and illustrate its potential value in the planning of BRT systems.

Efeito do treinamento físico e da desnutrição durante a gestação sobre os eixos cranianos de ratos neonatos

In critical periods of body development, environmental stimuli such as physical exercise and diet may influence on placental flow and fetal somatic growth. The aim of this study was to evaluate the effects of physical training and malnutrition during pregnancy on the skull axis of newborn rats. Male Wistar rats were divided according to manipulation of their mothers: untrained control (Cf, n = 25), trained (Tf, n = 25), untrained and malnourished (Mf, n = 25), trained and malnourished (TMf, n = 25). Trained mothers (T and TM) were submitted to 8 weeks of moderate physical training before and during pregnancy (60min/day, 5 days/wk to 65% of VO2max). Malnourished mothers (M and TM) received a low protein diet during pregnancy (8% casein) while the nourished (C and T) were fed with normal diet (17% casein). On the 1st postnatal day, the number of pups born per litter, litter weight and birth weight, latero-lateral axis of skull (LLAS) and antero-posterior axis of skull (APAS), longitudinal axis of the body (LA) and length of tail (LT) of each neonate were verified. On the 3rd day after delivery, the brains were extracted and weighed. During pregnancy, the females of the T and M groups showed lower weight gain compared with group C at 3rd week (C = 34.4 ± 1.3, T = 30.7 ± 0.60, M = 25.8 ± 0.78, TM = 29.9 ± 0.83). The malnourished group had lower birth weight in relation to their respective controls (Cf = 6.3 ± 0.1, Tf = 6.3 ± 0.1, Mf = 4.7 ± 0.07; TMf = 5.0 ± 0.06). Group Mf presented measures of LLAS (Cf = 9.8 ± 0.06, Tf = 9.8 ± 0.05, Mf = 9.2 ± 0.04; TMf = 9.6 ± 0.13) and EAPC (Cf = 18.1 ± 0.1, Tf = 18.2 ± 0.1, Mf = 17.5 ± 0.1, TMf = 18.0 ± 0.2) lower compared to controls. Based on the results, it can be concluded that malnutrition during fetal period changed somatic development, while physical training positively influenced on the skull axis of the concepts.