Acid-base physiology at rest, during exercise and in response to training

Effect of Lactate Minimum Speed-Guided Training on the Fluid, Electrolyte and Acid-Base Status of Horses

“…The decreased Cl − in blood after exercise is commonly observed since this is the electrolyte lost in greater concentration by sweat [42]. Additionally, this reduction may also have been caused by the greater displacement of Cl − to red cells in exchange for HCO 3 − , as the latter was reduced at the end of the exercise [43]. Despite this, there was no hypochloremia, as observed in show jumping horses [25], which was in contrast to what was found in racehorses [40], endurance horses after 65 km [36] and stallions after marcha exercise [34].…”

Traditional and quantitative analysis of acid‐base and electrolyte imbalances in horses competing in cross‐country competitions at 2‐star to 5‐star level

“…The tendency to a slight metabolic alkalosis, as indicated by a relatively high proportion of pre‐exercise samples with pH, HCO 3 − , BE ECF , SID 4 , and p CO 2 values that were increased above the expected range, previously has been reported in athletic horses and may be the result of training‐induced increased buffer capacity of the blood or the composition of the diet. Diets with high cation‐anion difference induce a mild systemic strong ion alkalosis that may be characterized by increased plasma Na + , HCO 3 − , and tCO 2 concentrations and decreased plasma Cl − concentrations . Because no information about the diets of the investigated horses was obtained, an influence of the diet on resting acid‐base values cannot be excluded.…”

“…The increase in TP concentration that typically occurs in exercising horses primarily results from a rapid osmotic fluid shift from the vascular compartment into contracting skeletal muscle with the onset of exercise. The increase in extracellular K + concentration additionally results from the efflux of K + from contracting skeletal muscle to the extracellular compartment and is associated with the occurrence of muscle fatigue . The decrease in Cl − concentration may have been associated with Cl − losses via sweating or an increased Cl − shift from plasma into red blood cells in exchange for HCO 3 − .…”

Science‐in‐brief: The 9th Meeting of the International Conference on Equine Exercise Physiology 2014. Biochemistry, nutrition and cardiorespiratory function of athletic horses

“…In the biochemistry section, several investigators presented work related to the use of total plasma carbon dioxide concentration (tCO 2 ) as a method of identifying the illegal administration of alkalinising agents prior to competition . Measurement of tCO 2 prior to athletic competition is commonly enforced in track racing jurisdictions in many countries, with a variable upper allowable threshold depending in part on whether furosemide administration is permitted prior to competition . It should be recognised that a variety of other factors can also affect tCO 2 in horses, and since the consequences of a positive result are substantial, the accuracy and reliability of this method are critical .…”

“…Measurement of tCO 2 prior to athletic competition is commonly enforced in track racing jurisdictions in many countries, with a variable upper allowable threshold depending in part on whether furosemide administration is permitted prior to competition . It should be recognised that a variety of other factors can also affect tCO 2 in horses, and since the consequences of a positive result are substantial, the accuracy and reliability of this method are critical . One of the studies presented at ICEEP 9 described the measurement of plasma tCO 2 in 8 healthy sedentary horses 3 times a day for 5 days .…”