Some metabolic effects of maximal exercise in the horse and adaptations with training.

The study examines how maximal physical exercise affects the horse’s metabolism both before and after a 10-week training program, with specific attention on changes in the blood composition.

Objective and Methods

• The objective of the study was to better understand the metabolic effects of maximal exercise (specifically galloping) on horses, and to observe changes after a period of targeted training.
• Six horses underwent incremental exercise before and after a 10-week training program.
• Determinations were done on venous blood to measure numerous variables such as packed cell volume, total plasma protein, glucose, glycerol, lactate and others.

Key Findings

After maximal exercise, there were notable changes in the horses’ blood composition, some of which could be altered with training.

• There was an increase in blood glucose levels.
• A significant increase in glycerol was observed, peaking 30 minutes following exercise. This increase was larger post-training.
• There were smaller increases in free fatty acids following training.
• Lactate levels were heightened after training.
• A noticeable fall in pH after maximal exercise, but this decrease was less pronounced post-training.
• A spike in the production of 11-hydroxycorticosteroids was observed, implying a possible quicker return to resting levels post-training.

Conclusion

The study reveals that with maximal exercise in horses, both glycogen and free fatty acids served as important energy sources for working muscle. After training, there is increased utilization of these energy substrates. This explains why the horses were able to better handle metabolic changes stimulated by high-intensity exercise after training. This research deepens our understanding of the metabolic adaptation of horses to exercise and could influence the design of effective training programs for equine athletes.