Biomarkers test vs exercise stress test: In biomarkers test, in this process, the levels of cortisol (hormone secreted by adrenal gland) and other blood parameters that are affected by stress. Significant correlations have been observed between blood cortisol concentrations, especially during stress whereas in exercise stress tests you have to walk or run on the treadmill you will be hooked to an electrocardiogram (EKG) machine that will monitor your heart to understand how your heart is cpoing up with Physical stress.