Electrocardiography, heart scope and haematology of horses competing in an endurance ride.

The research investigated the effect of a 100 kilometre endurance ride on the heart health and hydration levels of 31 horses, demonstrating that faster horses had significantly increased heart scores and signs of dehydration, but no electrocardiogram abnormalities were observed.

Heart Health and Performance

• The study began by recording the electrocardiograms – electrical activity tracing of the heart – of all participating horses before and after the endurance ride. From these electrocardiograms, the researchers were able to calculate a heart score for each horse.
• The study found that horses which completed the 100 kilometre endurance ride at a faster pace had significantly higher heart scores as compared to their slower counterparts or those removed from the ride due to inadequate recovery of heart rate. It’s important to note here that a high heart score generally indicates a higher level of cardiac work and stress, potentially signalling better endurance capabilities in these horses, although more research would be needed to confirm this.
• Interestingly, despite this difference in heart scores, the study found no abnormalities in the electrocardiograms recorded after the ride, suggesting that participating in the endurance ride, irrespective of the speed, doesn’t induce adverse heart conditions.

Hydration Levels and Performance

• In addition to the heart health, the study also examined the horses’ hydration levels through the ride by taking blood samples. They assessed packed cell volume (PCV) and total plasma protein (TPP) levels of all horses before, at the midway, and at the end of the ride.
• PCV, essentially the ratio of the volume of red cells in blood to the total volume of blood, and TPP are common test parameters used to calculate levels of hydration and determine if dehydration has occurred.
• The results demonstrated that the horses did appear to become dehydrated during the ride, as evidenced by the increase in PCV values, especially in the group of fast-paced horses. The dehydration in these horses was significantly higher during both the mid-ride and the end sampling times as compared to the slower group.
• However, observation of the TPP values showed no significant differences in the level of dehydration between the faster and slower groups of horses. The TPP values remained fairly stable, indicating—it could be argued—that the horses’ bodies were managing to maintain certain basic physiological norms, despite the exertion and dehydration hinted at by the elevated PCV values.

Conclusion and Recommendations

• The study is useful in providing insights into the physiological impact of endurance riding on horses, especially in relation to cardiac activity and dehydration issues.
• However, the findings draw attention to the need for proper management techniques including sufficient hydration and electrolyte balance support for horses during such endurance rides to prevent any adverse health risks.