The Influence of Training and Simulated Race on Horse Plasma Serotonin Levels.
Authors: Medica Pietro, Giunta Renato Paolo, Bruschetta Giuseppe, Ferlazzo Alida Maria
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Circulating serotonin (5-HT) represents a marker of physiological stress response in exercising horses, yet little is known about how different training intensities affect peripheral levels in sport horses. Medica and colleagues measured plasma 5-HT in eighteen trained horses at rest, 30 minutes post-exercise, and 2 hours post-exercise following both routine training sessions and a simulated race protocol, using ELISA analysis of platelet-poor plasma. Both exercise types significantly elevated plasma 5-HT at the 30-minute timepoint compared with baseline, with the simulated race producing substantially higher 5-HT concentrations than standard training—findings the authors attribute to increased platelet release and enhanced peripheral synthesis triggered by the metabolic demands of exercise. By two hours post-exercise, 5-HT concentrations had normalised to resting levels in both conditions, suggesting the serotonergic system rapidly restabilises once acute exercise stress resolves. For practitioners, these findings suggest that peripheral serotonin dynamics could complement existing fitness and stress assessment protocols when evaluating individual horses' physiological adaptation capacity, potentially informing training load management and sport horse selection decisions.
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Practical Takeaways
- •Peripheral serotonin levels may serve as a biomarker for assessing individual horse physiological adaptation capacity to training and competition stress
- •Simulated races produce a more pronounced acute serotonin response than routine training, suggesting different physiological demands between these exercise modalities
- •Monitoring 5-HT response could complement existing performance assessment techniques in sport horse selection and training program evaluation
Key Findings
- •Plasma 5-HT levels significantly increased at 30 minutes post-exercise in both training and simulated race sessions compared to baseline
- •Simulated race induced significantly higher plasma 5-HT at 30 minutes (T1) compared to training sessions
- •Plasma 5-HT concentrations returned to physiological baseline levels by 2 hours post-exercise in both sessions
- •Exercise-induced 5-HT elevation likely results from increased platelet release and/or enhanced peripheral synthesis