Oxidative damage is present in plasma and circulating neutrophils 4 weeks after a high mountain expedition

It is well known that exposure to extreme environments, such as in high-mountain expeditions, is associated with increased production of reactive oxygen species and related oxidative damage. However, there is little information concerning antioxidant recovery after this type of expedition. Thus, the aim of this study is to analyze the antioxidant recovery status at sea level of five expert alpinists 4 weeks after climbing Cho-Oyu (8,201 m). Body composition, cardiorespiratory capacity, and circulating parameters were almost similar to the values obtained at the beginning of the study. However, the alpinists presented high erythrocyte number, related hemogram values, and ferritin. Sodium, alkaline phosphatase, and γ-glutamyltransferase plasma levels were lower. Concerning oxidative stress, plasma uric acid levels were significantly increased, as well as malondialdehyde and protein carbonyls. Neutrophils displayed significantly higher levels of malondialdehyde and lower catalase activity. Therefore, these data indicate that the oxidative stress during a high mountain expedition is the most probable cause to explain an incomplete recovery in plasma and neutrophil antioxidant status.