Comparison of β-endorphin, Lactate and Cortisol Concentrations in Winning and Losing Racehorses.
Authors: Tavanaeimanesh Hamid, Dashli-Boroon Omid Jahed, Corley Kevin
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Biochemical markers may offer insight into performance outcomes in racehorses, prompting researchers to examine whether endogenous opioid activity, metabolic fatigue and stress responses differ between competitive winners and losers. Blood samples from 44 horses competing in a 1000-metre national championship were analysed immediately post-race and 20 minutes later, comparing β-endorphin, lactate and cortisol concentrations between the top two finishers and the last two finishers. Winning horses demonstrated notably elevated β-endorphin levels alongside reduced lactate accumulation at both sampling timepoints, suggesting superior anaerobic efficiency and pain modulation; cortisol showed no meaningful differences between groups. Whilst these findings warrant cautious interpretation given the modest sample size and statistical limitations, the association between higher endogenous opioid activity and lower fatigue markers in successful competitors could have implications for understanding recovery protocols, fitness assessment and perhaps identifying physiological traits that correlate with competitive aptitude—though the authors appropriately emphasise that further rigorous investigation is needed before drawing conclusions about causation or practical application.
Read the full abstract on PubMed
Practical Takeaways
- •Higher β-endorphin and lower lactate levels may be biomarkers of superior racing performance, though causation remains unclear
- •Cortisol monitoring alone appears insufficient for predicting race outcomes or assessing competition stress in racehorses
- •Further research is needed before these biochemical markers can be reliably used for training adjustments or pre-race conditioning decisions
Key Findings
- •Winning horses had significantly higher β-endorphin concentrations at T0 and T20 compared to last-place horses (P > 0.05)
- •Winning horses had significantly lower lactate concentrations at T0 and T20 compared to last-place horses (P > 0.05)
- •Cortisol concentrations showed no significant differences between winning and losing groups
- •Within-group differences in β-endorphin and lactate were significant between T0 and T20 timepoints (P < 0.05)