This paper evaluates the hemodynamics of 30 young men, aged 17-19 years, with borderline hypertension (BHT) and 29 normotensive (NT) patients within the same age range. The study has been carried out using the impedance cardiography method at rest and under passive orthostatic test, cold test, and hyperventilation test. In the BHT patients, the following features have been observed: increased values of the cardiac index (CI), stroke volume index (SVI), mean blood pressure (MBP), and left ventricle work index (LVWI), as well as the accompanying normal values of the total peripheral resistance index (TPRI). The reactions of the cardiovascular systems during the functional tests are similar in both tested groups; however, they are most clearly distinct in the BHT patients, where the differences are statistically significant. This may support the argument that the activity of the adrenergic system in this group in intensified.