abstract: Purpose: The purpose of this study was to examine the acute effects of two novel intermittent exercise prescriptions on glucose regulation and ambulatory blood pressure. Methods: Ten subjects (5 men and 5 women, ages 31.5 &plusmn; 5.42 yr, height 170.38 &plusmn; 9.69 cm and weight 88.59 &plusmn; 18.91 kg) participated in this four-treatment crossover trial. All subjects participated in four trials, each taking place over three days. On the evening of the first day, subjects were fitted with a continuous glucose monitor (CGM). On the second day, subjects were fitted with an ambulatory blood pressure monitor (ABP) and underwent one of the following four conditions in a randomized order: 1) 30-min: 30 minutes of continuous exercise at 60 - 70% VO2peak; 2) Mod 2-min: twenty-one 2-min bouts of walking at 3 mph performed once every 20 minutes; 3) HI 2-min: eight 2-min bouts of walking at maximal incline performed once every hour; 4) Control: a no exercise control condition. On the morning of the third day, the CGM and ABP devices were removed. All meals were standardized during the study visits. Linear mixed models were used to compare mean differences in glucose and blood pressure regulation between the four trials. Results: Glucose concentrations were significantly lower following the 30-min (91.1 &plusmn; 14.9 mg/dl), Mod 2-min (93.7 &plusmn; 19.8 mg/dl) and HI 2-min (96.1 &plusmn; 16.4 mg/dl) trials as compared to the Control (101.1 &plusmn; 20 mg/dl) (P < 0.001 for all three comparisons). The 30-min trial was superior to the Mod 2-min, which was superior to the HI 2-min trial in lowering blood glucose levels (P < 0.001 and P = 0.003 respectively). Only the 30-min trial was effective in lowering systolic ABP (124 &plusmn; 12 mmHg) as compared to the Control trial (127 &plusmn; 14 mmHg; P < 0.001) for up to 11 hours post exercise. Conclusion: Performing frequent short (i.e., 2 minutes) bouts of moderate or high intensity exercise may be a viable alternative to traditional continuous exercise in improving glucose regulation. However, 2-min bouts of exercise are not effective in reducing ambulatory blood pressure in healthy adults. / Dissertation/Thesis / Ph.D. Physical Activity, Nutrition and Wellness 2013

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / Physical exercise acts positively against the related risk factors for systemic arterial hypertension, a chronic and non-communicable disease that affects, approximately, 30% of the world population. Even though there are numerous studies that investigated the physiological responses of the exercise in this population, studying the "dose response" of its fractionation throughout the day becomes necessary, allowing new prescription possibilities. Therefore, this study aimed to evaluate ambulatory blood pressure kinetics after a fractionation of concurrent exercise session, as well as the nitric oxide bioavailability in hypertensive middle-aged women. In this way, eleven hypertensive middle-aged women (57.45 ±5.13 years) voluntarily participated of this study and underwent three experimental sessions and one control day (CS). In the morning (MS) and night (NS) sessions, the exercise was fully paid up in the morning and evening, respectively. In fractionized session (FS), it held 50% of the volume in the morning and the remaining 50% on the night shift. It was found that the MS provided greater decay and lower blood pressure reactivity (p<0.05) for systolic blood pressure (SBP) and diastolic blood pressure (DBP) 1h post-exercise, when compared to CS. The MS was also more effective in post-exercise hypotension for SBP than NS and FS, and promoted greater attenuation to pressure reactivity (p<0.05) than the other sessions. By analyzing the ambulatory blood pressure kinetic following the exercise, it was shown that the FS promoted lowest area under the blood pressure curve (p<0.05) for the SBP, DBP and MAP during sleep, as well as greater nitric oxide bioavailability (p<0.05) than the other sessions. In this sense, it is concluded that the FS was more effective in lower BP values at 24 hours following the exercise that other sessions, although this reduction has not been observed acutely, as observed after MS. / O exercício físico pode atuar positivamente contra os agravos correlatos à hipertensão arterial sistêmica, doença crônica e não-transmissível que incide aproximadamente 30% da população mundial. Embora existam evidências suficientes sobre as respostas fisiológicas do exercício físico nesta população, estudar a dose-resposta do seu fracionamento ao longo do dia se faz necessária, permitindo novas possibilidades para a prescrição do exercício físico. Assim, o objetivo deste estudo foi avaliar as respostas pressóricas, em até 24h, após o fracionamento de uma sessão de exercício concorrente, bem como a biodisponibilidade do óxido nítrico em mulheres hipertensas. Para tanto, participaram do presente estudo 11 mulheres hipertensas de meia-idade (57,45 ±5,13 anos) submetidas a 3 sessões experimentais e um dia controle (SC). Nas sessões manhã (SM) e noite (SN), o exercício foi realizado integralmente pela manhã e pela noite, respectivamente. Na sessão fracionada (SF), realizou-se 50% do volume pela manhã e os demais 50% no turno da noite. Verificou-se que a SM proporcionou maior decaimento e menor reatividade pressórica (p<0,05) para a pressão arterial sistólica (PAS) e para pressão arterial diastólica (PAD) 1h após o exercício, quando comparada à SC. A SM também foi mais eficiente em promover hipotensão pós-exercício para a PAS que a SN e a SF, além de promover maior atenuação à reatividade pressórica (p<0,05) que as demais sessões. Ao analisar a cinética pressórica nas 24h subsequentes ao exercício, foi evidenciado que a SF promoveu menor área abaixo da curva pressórica (p<0,05) para a PAS, PAD e PAM no período do sono, além de maior biodisponibilidade (p<0,05) do óxido nítrico que as demais sessões. Neste sentido conclui-se que que a SF foi mais eficaz em promover reduções pressóricas nas 24h subsequentes à prática de exercício físico que as demais sessões, ainda que esta redução não tenha sido evidenciada no período de 1h pós-exercício, como observada após a SM.