Effects of high intensity exercise on serum electrolytes and protein in Thoroughbred horses

This study investigated the physiological responses of five clinically healthy and regularly trained Thoroughbred horses to exercise in a 1800 meters course. Venous blood samples were collected at rest, immediately after the race, following 30 and 60 minute resting. The effects of race on venous acid-base balance, potassium, sodium, chloride, calcium, phosphorus, magnesium, total protein, albumin, and α 1-, α 2-, β- and γ-globulins, were investigated. Exercise had a significant effect on phosphorus, potassium, magnesium, chloride, sodium, calcium, total protein, albumin, α 1 and α 2-globulins levels. After the race a significant increase was recorded in the concentrations of the above-mentioned parameters. A significant linear correlation was found between values of albumin and calcium. During maximal exercise loading, changes in potassium, sodium and protein concentrations are due to acute shifts of fluid from the extracellular to the intracellular space, and returned to its basal values within 30 minutes after exercise. Changes of chloride levels likely depend on shift phenomena between intra- and extracellular compartment involving erythrocytes. During maximal exercise adrenergic stimulation induces PTH secretion, that might have influence on the changes of blood calcium, phosphorus and magnesium concentrations.