Dynamic Metabolic Response, Clotting Times and Peripheral Indices of Central Fatigue in Horse Competing in a 44 Km Endurance Race.
Authors: Arfuso Francesca, Giannetto Claudia, Interlandi Claudia, Giudice Elisabetta, Bruschetta Antongiulio, Panzera Maria Francesca, Piccione Giuseppe
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Metabolic and Fatigue Responses in 44 km Endurance Racing Researchers tracked six horses competing in an official 44 km endurance race to characterise the dynamic metabolic changes, coagulation status and central fatigue markers that occur during and immediately following prolonged competition. Blood samples collected at rest, within 5 minutes of finishing, and at 30 and 60 minutes post-race revealed significant metabolic shifts: lactate and non-esterified fatty acids remained substantially elevated throughout recovery, glucose dropped markedly and remained low, whilst the tryptophan-to-branched-chain amino acid ratio (a proposed indicator of central fatigue) increased persistently. Coagulation parameters showed notable changes too, with thrombin time extended at all post-race timepoints and fibrinogen peaks occurring immediately after exercise before declining by 30 minutes. These findings demonstrate that endurance horses rely heavily on lipid and amino acid metabolism to fuel prolonged effort, and that both central fatigue development and coagulation dynamics are measurable consequences of the 44 km distance. For practitioners, the persistent elevation of fatigue markers and metabolic byproducts through the first hour of recovery suggests that post-race management—including staged recovery, adequate nutrition, and monitoring for complications—warrants careful attention, whilst the transient coagulation changes highlight the physiological stress these athletes experience.
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Practical Takeaways
- •Endurance horses activate glycolysis and lipid mobilization during 44 km races; ensure adequate pre-exercise conditioning and carbohydrate/fat supplementation for sustained energy availability
- •Post-race metabolic and clotting alterations persist for at least 60 minutes; monitor recovery protocols and allow appropriate rest periods before returning to work
- •Elevated tryptophan/BCAA ratios post-exercise suggest central fatigue development; incorporate amino acid management into endurance training programs to optimize recovery and performance
Key Findings
- •Lactate, non-esterified fatty acids, and branched-chain amino acids increased significantly within 5 minutes post-race and remained elevated at 30 and 60 minutes (P < 0.0001)
- •Blood glucose decreased significantly at 5, 30, and 60 minutes post-race compared to rest (P < 0.0001)
- •Thrombin time increased at 5 minutes post-race and remained elevated but decreased by 30-60 minutes post-race (P < 0.0001)
- •Fibrinogen peaked at 5 minutes post-race then decreased by 30-60 minutes, indicating acute phase response to prolonged 44 km endurance exercise