The purpose of this study was the exposure of body to oxygen deficit via interval training for assessing cardiorespiratory fitness. In interval hypoxic training, subjects control and reduce their respires in specific manners. In this study, exercises began from three steps and finished with six steps (For example, step 1, 2, 3 inspiration - step 4, 5, 6 inspire retention and step 7,8,9 expiration). Before and after exercises, maximal aerobic capacity, resting heart rate, and erythropoietin were measured. Subjects were physical education students (n=30, age=18 ±2) divided in three groups. One of the experimental groups performed interval running and another experimental groups performed interval hypoxic training. Control group didn't carry out any activity. The results indicate that interval group has significant difference with control group in maximal aerobic capacity and resting heart rate, but has no difference in erythropoietin Interval hypoxic group has significant difference with control group I in maximal aerobic I capacity, resting heart rate and erythropoietin.