Characteristics of electrolyte and acid-base changes in horses in cros
s-country training are outlined. Changes in electrolytes in cross-coun
try horses include an increase in sodium, potassium, and phosphorus an
d a slight decrease in chloride. Ionized calcium and bicarbonate decre
ased significantly in the study. The acid-base status of these horses
was characterized by a mild acidosis despite lactate increases compara
ble to those found in the racing Thoroughbred.