what causes st depression on ekg?
 ST depression in general means subendocardial ischemia, meaning mild ischemia. However, it can also be due to changes in repolarization due to left ventricular hypertrophy depending on which EKG leads the ST depression is found in. So it is plausible that you have some left ventricular hypertrophy as a result of exercise and that is resulting in ST depression. 