The effects of an endurance ride on metabolism and neutrophil function.

The research investigates the impacts of an endurance ride on neutrophil functions, metabolic changes, and cortisol levels in trained horses. The study also explores potential alterations in neutrophil functional capacities due to these changes.

Study Methodology

• The research was carried out on 7 horses aged between 9 and 15. These horses underwent an endurance ride.
• Blood samples were taken from the horses one day before the ride, 30-60 minutes after the ride, one day after, and again 8 days post-ride.
• These blood samples were studied for various markers including cortisol levels, neutrophil:lymphocyte ratio, and the neutrophils’ ability to engulf yeast. Other markers such as leukotriene B4 production and respiratory burst were also monitored.
• Metabolic indicators like blood glucose level, serum lactate level, and muscle glycogen stores were also analyzed.
• The study also observed CK activity which was measured before and after the race.

Findings

• The endurance ride resulted in elevated serum cortisol levels and an increased neutrophil:lymphocyte ratio. This indicates hormonal changes due to the physical exertion encountered during the ride.
• The neutrophil’s ability to engulf yeast was enhanced immediately after the race, suggesting activation of this particular immune response after the endurance ride.
• However, a day after the ride, there was a decrease in leukotriene B4 production, a substance needed for neutrophil functionality, and in the respiratory burst, an indicator of the host’s immune response, signifying a possible dampening of these immune parameters after initial activation.
• No noticeable changes were detected in blood glucose and serum lactate levels. This suggests that endurance-trained horses maintain their glucose metabolism efficiently, even under strenuous conditions.
• Also, after the race, muscle glycogen stores were found to be about one-third of the level noted after the 8-day recovery period, indicating the substantial use of glycogen stores during the ride.
• A significant increase in CK activity was observed post-race, denoting muscle damage due to the endurance ride.

Conclusions

• The findings conclude that an endurance ride results in both hormonal and metabolic changes in horses, which not only activate neutrophils but also induce alterations in their functional capacities.
• These insights can help in managing the health and fitness of endurance trained horses more effectively and might provide interesting analogues for human athletes as well.