Effect of time of day and physical exercise on inflammatory biomarkers in athletic horses.
Authors: Aragona Francesca, Giannetto Claudia, Piccione Giuseppe, Arfuso Francesca, Arrigo Federica, Costa Antonino, De Caro Salvatore, Cannuli Antonio, Fazio Francesco
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Circadian rhythms and exercise both modulate immune function, yet their combined effects on inflammatory markers in working horses remain poorly characterised. Aragona and colleagues measured white blood cell counts, lymphocyte subsets (CD4+ and CD8+ cells), total proteins, and key cytokines (IL-6, IL-1β, TNF-α) in trained saddle horses at different times of day, with and without physical exertion. The research demonstrates that both temporal variation and exercise intensity significantly alter inflammatory biomarkers, suggesting that baseline immunological assessments cannot be standardised across all measurement times without accounting for diurnal fluctuations and recent activity levels. For practitioners managing athletic horses, this finding has important implications: blood work interpretation requires contextualisation of sampling time and training schedule, recovery protocols may need adjustment based on the horse's circadian pattern, and post-exercise inflammatory responses should be evaluated within this physiological framework rather than against fixed reference ranges. Understanding these interactions between chronobiology and exercise physiology enables more precise clinical decision-making and refined performance monitoring in equine athletes.
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Practical Takeaways
- •Blood work interpretation in athletic horses must account for time of day and recent exercise history to avoid misdiagnosis of inflammatory conditions
- •Training load assessment and recovery monitoring should consider circadian rhythms in immune markers for optimal performance management
- •Standardise timing of pre- and post-exercise blood sampling in athletic horses to enable meaningful comparison of inflammatory status
Key Findings
- •Physical exercise induces measurable changes in inflammatory biomarkers including WBC count, leukocyte subpopulations (CD4+ and CD8+ cells), and cytokine levels (IL-6, IL-1β, TNF-α) in trained saddle horses
- •Time of day influences the magnitude and pattern of inflammatory biomarker responses to exercise
- •Total proteins and immune cell populations show circadian variation in response to physical activity