The time course of alterations in plasma lipid and lipoprotein concentrations during eight weeks of endurance training.

Sixteen subjects (male = 7, female = 9) participated in 8 weeks of endurance training (70% VOmax, 30 min/day, 3--4 days/wk). Plasma lipid and lipoprotein concentrations in venous blood were assessed prior to and at 2-week intervals during the 8 weeks of training. VO2max was determined prior to training and at 4-week intervals. Body composition was assessed pre- and post-training. Results indicate that after an insignificant decline at 2 weeks (53.8 leads to 51.1 mg/dl), plasma high density lipoproteins (HDL) increased significantly (P < 0.05) at 8 weeks of training (51.1 leads to 57.4 mg/dl). This increase was linear after 2 weeks (r = 0.98) with a slope of +1 mg/dl/wk. This pattern of change was similar in males and females. VO2max (42.2 leads to 43.8 leads to 45.9 ml/kg x min) and time to exhaustion on the treadmill (6.9 leads to 8.0 leads to 9.1 min) increased significantly (P < 0.05) during training. Relative fat was not related to any lipid or lipoprotein group. Total cholesterol showed wide variations between sampling periods but was not significantly changed during the training period. Plasma triglycerides decreased significantly from 4 to 8 weeks of training, a period when HDL's were increasing. Over the last 4 weeks of training, the relationship between HDL's and triglycerides was significant, r = --0.65 (P < 0.05). These results suggest that alterations in HDL's lag behind changes in total cardiovascular fitness and increase simultaneously with a decline in plasma triglycerides after 4 weeks of endurance training.