Fluid, electrolyte, and acid-base responses to exercise in racehorses.

The research article focuses on how exercise impacts fluid, electrolyte, and acid-base balance in racehorses, particularly during high-intensity and short-distance training. The study delves into the mechanisms of these changes and the factors influencing them, including health, diet, supplements, and medication.

Mechanisms of Acid-Base Disturbances

• The article identifies anaerobic oxidation of glucose to lactic acid as a primary cause of metabolic acidosis in racehorses during high-intensity exercise. This physiological phenomenon leads to increased acid levels in the bloodstream, often referred to as metabolic acidosis.
• Such acid-based disturbances occur when the body’s energy demand outstrips the capacity of the oxygen-dependent aerobic systems, forcing the body to rely more on anaerobic metabolism, which produces lactic acid.
• Training effects are also discussed here, emphasizing how a well-trained horse can handle this acid-base shift better than a poorly trained one due to an increased buffer capacity.

Fluid Shifts and Electrolyte Changes

• During intense exercise, there is a decrease in plasma volume due to water transferring from blood vessels to intracellular and interstitial spaces. This massive shift in fluids, combined with active ion-exchange between blood and tissues, leads to significant alterations in electrolyte concentrations.
• Understanding these changes in horses can help in devising strategies to maintain good health, performance, and recovery in equine sports.

Influence of Health, Diet, and Medication

• The research further emphasizes the influence of factors like overall health, diet, and supplements on how a horse’s body deals with exercise-induced imbalances.
• A nutritionally balanced diet, particularly maintaining a balanced dietary cation-anion, is considered crucial for neutralizing acidosis and preventing disturbances in electrolyte balance.
• Specific medications, such as creatine, sodium bicarbonate, and furosemide, are identified as influential in managing these fluid, electrolyte, and acid-base balance issues in racehorses.

Importance of Buffer Capacity and Lactic Acid Distribution

• The research highlights buffer capacity, the body’s ability to neutralize acids and maintain pH, as an essential factor in how well a horse’s body can control acid-base imbalances during exercise.
• Lactic acid distribution and its clearance from the body during and after exercise is also referenced as important considerations for understanding and managing exercise physiology in racehorses.