Thermal stress and oxidant–antioxidant balance in experienced and novice winter swimmers

Abstract

The adaptation of human organism to environmental stress plays an important role in maintaining good health. The exposure to both low and high ambient temperature may provoke thermal stress and such a condition potentially leads to the excessive production of reactive oxygen species, which may result in oxidative stress. The purpose of the study was to determine the effect of one session of swimming in ice-cold water and one hot sauna session (performed few months later) on oxidant–antioxidant balance in two groups of healthy volunteers: 21 experienced winter swimmers and 19 people who participated in winter swimming for the first time (novices). The activity of antioxidant enzymes: catalase, superoxide dismutase and glutathione peroxidase was measured in erythrocytes of studied persons. Moreover, in blood plasma and erythrocytes the concentration of lipid peroxidation products was estimated. No statistically significant differences in initial values of antioxidant enzymes activity and lipid peroxidation products level were revealed between experienced and novice winter swimmers. The crucial antioxidant enzyme that neutralizes reactive oxygen species generated as a result of thermal stress seems to be catalase, since statistically significant changes of CAT activity after sauna were observed. Increased TBARS level observed as a result of sauna bath proves that exposure of organism to high ambient temperature is a source of oxidative stress. However, such a stress was hardly noticed in regular winter swimmers. The regular baths in cold water combined with sauna probably lead to adaptive changes that protect the organism against harmful effects of thermal stress.