Blood metabolic profiling associated with a short-term intensive training period in elite male water polo athletes: an exploratory metabolomics study.

OBJECTIVE

This exploratory metabolomics pilot study employed non-targeted liquid chromatography-tandem mass spectrometry (LC‒MS/MS) to characterize serum metabolic profiles in elite male water polo athletes, thereby assessing physiological adaptation to high-intensity training. We aimed to provide a scientific basis for evaluating physical fitness and optimizing performance capacity in elite athletes.

METHODS

Sixteen male water polo athletes of the Chinese national team were recruited. All athletes underwent a one-week complete break following the end of the previous competitive season to mitigate accumulated fatigue and establish a true resting metabolic baseline. Fasting venous blood samples (5 mL) were collected at 7:00 AM on two time points: the first sample (E1) was collected before commencement of the official training week, and the second sample (E2) was collected immediately after the completion of that week of training. The data were analyzed via XCMS, MetaboAnalyst 6.0, SPSS 21.0, and GraphPad Prism.

RESULTS

(1) Metabolomic analysis identified 363 metabolites in total, 33 of which were differentially expressed between pre- and post-training time points. After one week of routine training, 11 metabolites were significantly up-regulated (p < 0.01), and 22 were significantly down-regulated (p < 0.01). (2) KEGG pathway analysis identified the top eight metabolic pathways, with MetPA further highlighting lysine degradation (p < 0.01) and vitamin B6 metabolism (p < 0.05) as key altered pathways. (3) Three metabolites were identified as potential markers associated with the training week changes in water polo athletes on the basis of significant alterations post-training. N6, N6, N6-trimethyl-L-lysine (p < 0.01) and 2-aminoadipic acid (p < 0.01) were significantly decreased, whereas 4-pyridoxic acid (p < 0.01) was significantly increased.

CONCLUSIONS

Non-targeted LC‒MS/MS provides a valuable tool for monitoring metabolic adaptations at the molecular level in aquatic athletes. In this exploratory study, we observed associated changes in the serum metabolome following intensive training, pointing to adjustments in amino acid and lipid metabolism. These findings offer preliminary insights for guiding fitness and performance optimization.