Background/Aim. Energy drinks (EDs) are widely used by athletes as ergogenic agents. The aims of this study were to determine the acute and chronic effects of Red Bull ® , one of the most consumed EDs, on cardiodynamics and parameters of oxidative stress in physically trained rats. Methods. Rats were subjected to a swimming practice (1h per day, 5 days a week, during 4 weeks). They were divided into 4 groups: rats that did not consume ED either before swimming or prior to sacrificing; rats that did not consume ED before swimming, but did consume ED 30 minutes prior to sacrificing; rats that consumed ED 30 min before every swimming training, but did not consume ED prior to sacrificing; rats that consumed ED 30 min before every swimming training and 30 min before sacrificing. After sacrificing, hearts were isolated and perfused according to Langendorff technique. The parameters of cardiac function were recorded, and also the levels of prooxidants were measured in the coronary effluent during coronary autoregulation. Results. Compared to the control group, acute administration of the ED had a positive inotropic effect (manifested as significantly higher level of maximum and minimum rate of pressure development in left ventricle), while chronic administration affected the isolated increase in systolic left ventricular pressure, which could be considered the potentially negative impact of the ED. Prooxidative effect of the ED was observed, which was more pronounced in chronic consumption. Conclusion. The main conclusion of our study is that chronic administration of the ED changes the cardiovascular response and redox status in acute consumption.