Lack of relationship between changes in adiposity and plasma lipids following endurance training

In order to study the effect of alterations in fat morphology and metabolism induced by exercise-training on plasma lipids, 13 healthy young men were subjected to a 20-week aerobic training program on bicycle. Training significantly increased maximal aerobic power (VO2 max) (P less than 0.001) and decreased per cent body fat (P less than 0.001). A significant reduction of mean adipocyte diameter and an increase in isolated fat cell epinephrine-stimulated lipolysis were also observed following training. However, with the exception of total cholesterol, no changes were noted in plasma lipids. Neither before nor after training were triglycerides and high density lipoprotein cholesterol (HDL-C) correlated with VO2 max, fat cell diameter and adipocyte-stimulated lipolysis. The present study demonstrates that an important fat loss (mean loss of fat = 3 kg) and a significant gain in VO2 max induced by endurance training do not necessarily produce an increase in HDL-C levels in normal male subjects. Moreover, changes in VO2 max, body fatness and in fat cell epinephrine-stimulated lipolysis produced by endurance training are not related to modifications in plasma lipids in healthy men.