Effect of time of day and physical exercise on inflammatory biomarkers in athletic horses.

INTRODUCTION

The present study aimed to investigate the effect of time of day and physical exercise on some inflammatory biomarkers (white blood cell count-WBCs, leukocyte subpopulation CD4 + and CD8 + cells, total proteins, Interleukins IL-6, IL-1β and Tumor Necrosis Factor TNFα) in trained saddle horses.

METHODS

Blood samples were collected from 10 horses before, immediately (following 5 min) and 1 h after the training session in the morning (am) and afternoon (pm).

RESULTS AND DISCUSSION

Statistical analysis showed increasing value of WBCs immediately and 1 h after exercise ( < 0.01: < 0.01) at am compared to rest. Lower CD4 + oncentration was observed immediately and 1 h after exercise ( < 0.01; < 0.01) at pm compared to rest and decreased levels 1-h post-exercise at pm compared to am ( < 0.001). CD8 + exhibited significant lower value at pm compared to am at each time point (before: < 0.01; immediately: < 0.01; 1 h after: < 0.001). IL-6 showed increasing value post-exercise at pm ( < 0.01). IL-6 and IL-1β levels were markedly elevated at pm compared to am at each time point ( < 0.0001; < 0.0001; < 0.0001). This information is essential for formulating suitable training regimens, considering performance in connection to possible daily risk for infection, illness, and inflammation to which the horse may be vulnerable.