Changes in the glutathione system of erythrocytes due to enhanced formation of oxygen free radicals during short-term whole body cold stimulus.

The red cell glutathione levels of 10 healthy volunteers who are accustomed to winter-swimming were measured before and after this short-term whole body exposition to hypothermic environment. From the increases of the erythrocytic level of oxidized glutathione (GSSG) and of GSSG: total glutathione ratio an extensive formation of oxygen free radicals during and following the exposition to the intensive cold stimulus was concluded. That is in accordance with the finding on the drastic decrease of the concentration of uric acid as an important radical scavenger of the human blood plasma. Furthermore, the initial erythrocytic concentrations of reduced glutathione (GSH) and GSSG of subjects accustomed to winter-swimming were compared with those of healthy control persons who are not accustomed to regular winter-swimming. The markedly increased concentration of GSH and the reduced GSSG:total glutathione ratio in the erythrocytes of winter-swimmers reflect the adaptation to a regular oxidative stress. This antioxidative adaptation is postulated as a new basic mechanism of the hardening by exposition to an intensive short-term cold stimulus often applied within the hydrotherapy.