Equine Athletes and Body-Wide Inflammation

Studies show that strenuous exercise causes body-wide inflammation. With this in mind, measuring systemic inflammation may be a useful tool for identifying horses at risk for elimination from endurance competitions due to musculoskeletal or metabolic disturbances.

“Examples of inflammatory mediators that show appreciable increases following endurance exercise include serum amyloid A; interleukins-6, -8, and -10; tumor necrosis factor-α; and matrix metalloproteinases,” explained Kathleen Crandell, Ph.D., an equine nutritionist for Kentucky Equine Research.

Most studies on inflammation and competition measure inflammatory mediators at the start and end of competition, providing little information regarding inflammation during competition. To help fill the gaps in knowledge about how much inflammation occurs in the middle of a ride and how horses respond to that inflammation, researchers^* recently mapped the activity of inflammatory mediators during the course of a 100-mile (160-km) endurance competition.

Specifically, data were obtained after collecting blood samples from 77 of 150 competitors entered in the 2018 Tevis Cup Ride. Samples were obtained and compared from horses prior to the ride, at the pre-ride veterinary examination, at the mandatory stops at 34 miles (55 km) and 68 miles (110 km), and again at the finish line.

In total, only 31 (40%) horses completed the ride, and various inflammatory mediators were compared between the horses that did and did not finish.

“While no overall differences in the production of inflammatory proteins were identified between finishers and non-finishers, there were some clear changes in protein levels noted during specific time points,” said Crandell.

These included an early and persistent increase in interleukin-8 and matrix metalloproteinase-1. In addition, an initial increase in the proinflammatory protein interleukin-1β was identified followed by a rapid decline back to normal levels.

“Further research is needed to identify short-lived changes in the production of inflammatory mediators. Such data may give insight into improving the overall welfare of the horse and higher completion rates,” Crandell said.

Current means of maximizing endurance success include sound nutritional management, appropriate training, and routine veterinary care. Appropriate nutritional management involves replenishing electrolytes after training and competition, as well as supplying antioxidants to squelch damaging free radicals produced during exercise. For optimal support, turn to Nano-E and Nano-Q10, two research-proven antioxidants from Kentucky Equine Research, as well as the company’s electrolyte products, including Race Recovery and Restore SR and Restore Paste.

^*Page, A.E., J.C. Stewart, C.L. Fielding, et al. 2019. The effect of a 160-kilometer competitive endurance ride on inflammatory marker mRNA expression in horses. Journal of Equine Veterinary Science. 79:45-49.