This work was undertaken to study tissue oxygen exchange and oxidative processes in the long-lived individuals who were assumed as the physiologically aging individuals. Oxygen tension was assessed in forearm subcutaneous cellular tissue by means of the polarographic method while performing 10 min oxygen inhalation tests (with spontaneous oxygemogram recording) and a 10 min clamping of vessels. The obtained data served as the tissue oxygen exchange indicator. This approach made us possible to evaluate the oxygen delivery and oxygen uptake. To study qualitative characteristics of oxidative processes, we assessed vacat-oxygen of the blood and urine and estimated the underoxidation coefficient proposed by Muller. We have found that tissue respiration intensity falls, the amount of underoxidated products of the blood and urine rises, and the underoxidation coefficient increases in aging. The decrease of tissue oxygen respiration intensity in subcutaneous cellular tissue reflects the development of tissue hypoxia associated with reduced activity of the enzymes, being involved in oxygen exchange. An age-related decrease of tissue perfusion leads to the formation of circulatory hypoxia and also contributes considerably to tissue hypoxia formation. The revealed changes in the tissue oxygen exchange and oxidative processes in the long-livers are generally correspondent to those that can be seen in the people of 80-89 years. This finding speaks in favor of the physiological aging in the long-livers.