[Changes in blood lipids in humans during long-term ski crossing in the Extreme North].

Serum lipids were measured in the men who made two ski crosses in the Far North during polar night. The first trip, which was to train the athletes, took 17 days and the second took 38 days. In both studies, lipid mobilization and utilization increased, which led to changes in the lipid spectrum: decrease of the concentration of LDL and, in the second trip, of VLDL and HDL3, and increase of the concentration of HDL2 and cholesterol HDL. In the second trip, lipids were most intensively utilized: lipolysis enhanced and free fatty acids declined. This was also indicated by an increase of the capillary-venous difference in terms of the total fraction of LDL and VLDL as well as free fatty acids. At the end of the second trip, the positive capillary-venous difference in terms of LDL and VLDL and, accordingly, the negative capillary-venous difference in terms of HDL2 and HDL3 increased. At the end of both trips the synthesis of transport lipids grew; in the most strenuous second trip, their active utilization in the working organs was stronger.