Vij, Anjana G., Ruma Dutta, and Narinder K. Satija. Acclimatization to oxidative stress at high
altitude. High Alt. Med. Biol. 6:301–310, 2005.—Hypoxia-mediated oxidative stress has been implicated
in the pathophysiology of high altitude maladaptations. To explore whether prolonged
exposure to high altitude can trigger an adaptive response to oxidative stress and restore redox
homeostasis in the body, the study was conducted to evaluate biochemical variables related to
oxidative stress and antioxidant status in humans at sea level (190 m) and following 3- and 13-
month sojourns at altitude (4500 m). After 3 months at altitude, whole-blood thiobarbituric acid
reactive substances (TBARS) were significantly higher (65.6%), nonenzymatic antioxidants like
ascorbic acid and caeruloplasmin were significantly lower (41% and 22%, respectively) and
plasma total antioxidant status (TAS), glutathione levels, and superoxide dismutase activity were
marginally altered as compared to their basal values. After 13 months at altitude, TBARS levels
regressed back to preexposure levels. Plasma total antioxidant status (TAS) improved by 21%,
glutathione levels by 32.8%, and plasma bilirubin by 35.8% as compared to sea level. Average
concentrations of ascorbic acid and caeruloplasmin were 18% and 37% higher as compared to
the subjects studied after a 3-month stay at high altitude. In addition, there was a progressive
rise in erythrocytic superoxide dismutase activity and persistent hyperurecemia. The study observed
that on prolonged exposure to high altitude humans could mount an effective adaptive
response to oxidative stress by activating the antioxidant defense. Hence, strengthening the antioxidant
defense could be an effective strategy to prevent free-radical-mediated pathophysiological
alterations and quicken acclimatization to oxidative stress.
