Black tea supplementation on physical activity in rats

Introduction: Physical activity is related to several health benefits, as blood pressure and body weight decreases, glucose tolerance and serum lipid profile improvement. However, it increases oxygen consumption leading to increasing of Reactive Oxygen Species production which generates damage to the organism, such as lipid peroxidation, protein carbonylation and DNA oxidation and, so, has some impact in the performance. Black tea, an infusion from the Camellia sinensis L. plants, is one of the most popular drink in the world. The high consumption of C. sinensis teas is due to the presence of high levels of antioxidants, which means they have beneficial effects in preserving human health when present in a regular diet, inhibiting the formation and propagation of ROS in the human organism. Objective: To verify the effects of different concentrations of black tea intake on healthy runners rat´s performance. Methods: Male rats (n = 7 of each group) were randomized separated into groups according to the black tea concentration and weeks of training (0, 5 and 10 weeks). The supplementation occurs in three concentrations in the liquid ingested by the animals: control (water), 50% of black tea (50% v/v), or 100% of black tea. The training happened in a treadmill without inclination and the running time and velocity were increased each week until the 5th week (20 m/s for 60 min.), which remains the same (from 6th to 10th week). An exhaustive test was performed after the end of the training period on 0, 5th and 10th week. Results: After 5 weeks of training it was observed an increase of running time on exhaustion test and performance (kg.m) of rats which ingested 50% of tea. The same results were verified after 10 weeks of training by the animals which received tea regardless of concentration. Also, regardless of the dose of tea ingested, the blood antioxidant capacity (measured by ORAC assay) was higher than the water intake after exhaustion test in both exhaustive tests. There was found no difference in the catalase, GR, GPx, and SOD antioxidant enzymes, as well as GSH reduced content, on serum among the control and tea groups. Regard to inflammatory markers, after 5 weeks of training was verified that the IL-6 was lower on serum of the animals which received 50% of black tea; however there is no difference after 10 weeks of training regardless of the tea concentration. The values of TNF-α and IL-1β had no difference between the supplementation doses in the same week of training. Conclusion: The black tea intake showed to increase the performance in the running without changing biochemistry parameters in healthy adult rats.