Background: We tested the hypothesis that endurance over-training could alter the favorable effects of well-tolerated training on lipid profile.
Methods: At weeks 1, 6, 15, 26, 36, and 47 of the training program, blood was drawn to test lipid profile of 20 endurance-trained rowers. Diet and caloric intake were controlled.
Results: Over-training was diagnosed in five subjects (loss of performance, asthenia, sleep disturbance...) at week 15 and lipid profile of well-trained and over-trained subjects were compared. Training improved cholesterolemic profile and lowered insulin resistance (HOMA-IR: -39 +/- 9%; p=0.02), and triglycerides concentration (-30 +/- 6%; p=0.05) in rowers who did not change to demonstrate over-training. Plasma LPL (+29 +/- 11%; p=0.01) and hepatic lipase (+5 +/- 3%; p=0.01) activities increased in this group suggesting higher TG utilization and turnover. After week 15 and regarding the well-trained condition for the five over-trained subjects, VLDL-TG (-13 +/- 7 %; p=0.03) and Apo-C(3) (-31 +/- 13%; p=0.01) concentrations decreased, while insulin resistance (+17 +/- 7%; p=0.03) and glycerol concentration (+17 +/- 3%; p=0.01) increased and hepatic lipase activity decreased (-14 +/- 4%; p=0.01).
Conclusion: Over-training was accompanied by alterations in the lipid profile, which appeared to be the consequence of over-training.