Effect of Infusion of Yerba Mate on Oxidative Stress, Physiology, and Performance of Trained Cyclists

In this study, participants will be randomized into three groups: a group with yerba mate infusion and carbohydrate meal, a group with only yerba mate infusion, and a group with water and carbohydrate. The washout period between treatments will be seven days. The experimental protocol will be carried out in the same period of the day (± 3h) to minimize the interference of biological variations.

Before starting the procedures for data collection, the individuals invited to participate in the study will be informed about the objectives and methods of the research and then, if accepted, they will sign the informed consent form. The study will be divided into four stages (baseline and the three different interventions). The baseline period comprises two meetings, the first of which is to carry out a questionnaire to identify the participant, to carry out blood collection of the intermediate vein of the arm, to make the analysis of body composition and to be instructed on the exercise and feeding procedures during the experimental protocol. In the second meeting of the baseline period, the participants will be submitted to an incremental protocol on the cycle ergometer, and the data from this test will be used for the application of the experimental exercise protocol performed later with dietary interventions. From the incremental test, the maximum aerobic power, peak oxygen volume, maximum heart rate, and lactate thresholds, energy substrate consumption, and perceived exertion will be determined. In the three visits following the baseline period, according to randomization, interventions will be carried out with the infusion of yerba mate and carbohydrate meal, with only the infusion of yerba mate and with water and carbohydrate meal. In intervention groups with yerba mate infusion, participants will be asked to ingest seven days before the exercise protocol the same amount of yerba mate infusion as the test day (250 mL). In this way, individual packages of ultra-refined yerba mate containing 5 g, the necessary materials, and guidelines for the proper preparation of the infusion will be provided. In groups that receive the carbohydrate meal, participants will be offered, one hour before starting the exercise protocol, white bread with corn syrup, which will be adjusted to their individual carbohydrate needs, in quantities that make up a total of 1g of carbohydrate per kg of bodyweight of the participant, as recommended by the American College of Sports Medicine and the Academy of Nutrition and Dietetics, Dietitians of Canada.

In all visits, participants will be instructed to arrive at the physical effort laboratory of the Federal University of Santa Catarina in a 10-hour overnight fast, following the protocols of dietary control and physical exercise in which they must maintain their usual pattern of exercises and food throughout the study, except for the restriction of the consumption of micronutrient food supplements, beverages with antioxidant and stimulating properties already known, such as green tea, black tea, and wines, which may interfere with the results of the study due to the similarity of bioactive compounds from yerba mate in the composition of these drinks. In all these visits in which there will be dietary intervention, the participants will assess their body composition and perform the exercise protocol to assess their performance.

In each of the three intervention visits, 60 minutes before the exercise protocol, a carbohydrate meal will be offered (for when the individual is randomized to the group in which this meal is consumed); 40 minutes before the exercise protocol, the infusion of yerba mate or water (250 mL) will be performed; immediately before the exercise protocol, blood will be collected from the intermediate vein of the arm to observe the increase in phenolics in the blood promoted by the ingestion of the yerba mate infusion. Soon after, it will be the realization of the effective exercise protocol to measure performance. During the execution of the exercise protocol, blood samples will be collected from the earlobe to check the variations of lactate and glucose. At the end of the exercise protocol, a new blood collection will be performed in the middle vein of the arm to assess biochemical variations that may have been influenced after exercise.