Efeito da suplementação de nitrato dietético na forma de uma dose aguda de suco de beterraba na resposta pressórica pós-exercício em homens com obesidade

Abstract

It has been shown that nitrate supplementation may reduce blood pressure in several populations. However, the effect of beetroot juice on post-exercise blood pressure response has not yet been studied. The objective of this study was to verify the effect of dietary nitrate supplementation, in the form of beetroot juice, on post-exercise blood pressure response in obese individuals. In a randomized, cross-over trial, 14 normotensive and obese men were randomly assigned to three experimental sessions: 1) beetroot juice with exercise (BJE, 200ml with ≈ 800mg nitrate), 2) fruit soda industrialized with exercise (FSE, 200ml of low-nitrate beverage), considered control with exercise and 3) control without exercise (CON, 200ml of drink with insignificant nitrate content). The exercise performed was of the moderate aerobic type, with intensity of 50% of the reserve heart rate and, lasting 40 minutes. The concentration of nitrites and total plasma nitrates (NOx) was evaluated at four moments: fasting (first day), 60 minutes (60min), 105 minutes (105min) and 165 minutes (165min) after drinking (experimental session). And 24-hour ambulatory blood pressure (24h) was also evaluated through ambulatory blood pressure monitoring (ABPM). For statistical analysis of the data, we used repeated measurements ANOVA and two-way ANOVA with repeated measurements (condition vs. time) for comparisons of variables between the experimental sessions. The results show that the plasma NOx concentration increased significantly only in the BJE condition at all times from 60min after the intake of beetroot juice, compared to FSE and CON. Ambulatory systolic blood pressure (SBP) decreased ~ 5.3 mmHg (p <0.05) during the first six hours post-exercise, resulting in a reduction of SBP by ~ 3 mmHg (p <0.05), and diastolic blood pressure (DBP) at ~ 2 mmHg (p <0.05) in the 24-hour period after the BJE session compared to FSE and CON sessions. In conclusion, beetroot juice potentiated ambulatory post-exercise BP responses in obese and normotensive men.