Suplementação de suco de beterraba rico em nitrato e respostas cardiovasculares e hemodinâmicas ao exercício de força reforçado excentricamente

Abstract

Beetroot juice has been an important topic in sports nutrition, professional and amateur athletes seek the best performance during the practice of physical activity and numerous factors can enhance performance during training. In this context, beet juice supplementation has been highlighted due to its potential ergogenic effect by increasing the availability of endogenous nitric oxide that triggers physiological responses in the cardiovascular system that contribute to a better sports performance, however, there is still a limitation of results in the scientific literature on resistance exercises that evaluate the modulation in the autonomic nervous system with the use of this supplementation. Given the above, this dissertation aimed to demonstrate the effects generated with the supplementation of beetroot juice in strength training. Therefore, it was divided into two chapters. Chapter 1 is a literature review article that aimed to demonstrate the influence of nitrate intake on cardiovascular and hemodynamic responses and performance to strength training. From the findings, it was evidenced that nitrate supplementation has positive physiological effects in training that improve performance and sports performance. However, these effects are not seen in all studies, due to the influence of certain variables such as physical conditioning, exercise duration and administered doses. Chapter 2 is a crossover, triple-blind, placebo-controlled trial that aimed to evaluate the effects of acute supplementation of nitrate-rich beetroot juice on cardiovascular and hemodynamic response to eccentrically reinforced strength training. It was observed in the study that nitrate supplementation induced a smaller increase in systolic blood pressure in response to eccentrically reinforced resistance exercise compared to placebo, in addition, supplementation induced a decrease in peripheral vascular resistance observed by the decrease in systolic blood pressure in the last series of eccentrically reinforced resistance exercise, however, the supplementation did not interfere in the heart rate response, the double product and in the oxygen saturation when compared to the placebo condition, and also did not interfere in the time under tension and in the subjective perception of effort in comparison with the groups. As the main outcomes of this work, we can conclude that the supplementation of beetroot juice rich in nitrate can be a nutritional strategy in resistance exercises, but its effects are still limited and more studies need to be developed to present better responses in strength training and to establish doses of effective supplementation and adequate manipulation in the variables of the physical training.