Alterations of lipid profile in endurance over-trained subjects

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-C₃ (−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.

Key words: Over-training, Leptin, Triglycerides, Cholesterol, Lipoprotein lipase