Acute and delayed effects of prolonged exercise on serum lipoproteins. II. Concentration and composition of low-density lipoprotein subfractions and very low-density lipoproteins.

To investigate the effects of a single period of prolonged exercise on lipoprotein concentration and composition, 13 healthy endurance-trained men were examined before and after (1 h, 20 h) a cross-country run [30 km, time: 130 (SD 7.4) min]. The data show that following acute exercise, serum triglyceride (TG) concentration were reduced (36%) as a consequence of a reduced number (31%) of very low density lipoprotein (VLDL) particles. Changes in composition of VLDL were present but less evident. In contrast to this, acute exercise did not induce significant changes in the average concentration of individual low-density lipoprotein (LDL) subfractions. However, changes in dense LDL [density (d) > 1.044 g.ml-1] concentration were significantly correlated to changes in serum TG: a reduction of dense LDL occurred in subjects with large reductions in serum TG. In addition, LDL composition changed significantly. Immediately (1 h) after exercise the TG content of all LDL subfractions was reduced. These reductions were significant in large (d = 1.006-1.037 g.ml-1) and small LDL (1.044-1.063 g.ml-1). It can be concluded therefore from our study that acute exercise primarily altered the composition of LDL subfractions while their concentration remained stable.