Cardiac health is a determinant of athletic performance. Typically endurance products test for VO2 max but only a few investigate the underlying mechanism of such improvement in total aerobic capacity. Vedic Lifesciences planned a trial for a Terminalia arjuna (TA) extract “Oxyjun” to study specifically the cardiac component of VO2 max by measuring the left ventricular ejection fraction (LVEF) in healthy young adults using 2D-echocardiography. Thirty-two healthy males, aged 18–40 years performing regular endurance exercise, were randomly assigned to the extract or placebo. Fifty-six days of Oxyjun supplementation significantly improved LVEF and decreased myocardial performance index. Oxyjun reduced fatigue as assessed by Borg’s rated perceived exertion scale. There was no significant change in creatine kinase-MB and troponin-T indicating no cardiac damage. Oxyjun significantly increased cardiovascular efficiency and improved cardiac conditioning in young healthy adults.