Effect of NaCI and NaHCO₃ on serum ionised calcium and blood gas status during sprinting

Abstract

Sodium bicarbonate is often administered to horses before racing in an attempt to delay fatigue and improve performance. We examined the effect of acid-base status on serum ionised calcium concentration (iCa) during high intensity exercise in 8 Standardbred mares. In a randomised, blinded, cross-over study, mares were administered each of 3 treatments, NaCl (0.7 g/kg bwt), NaHCO3 (1 g/kg bwt) in 3 l water, or 3 l of water only, 4 h before performing a standardised exercise test to fatigue on a treadmill. Mixed venous blood samples were collected as the horses ran for 5 min at 3 m/s, to fatigue at a predetermined speed (approximately 113% VO2max) and for 5 min at 3 m/s. There was no effect of treatment on time to fatigue (P = 0.744). NaHCO3 attenuated (P<0.05) the exercise-induced decrease in venous pH (mean +/- s.e. 6.97, 6.95 and 7.06 +/- 0.02 at end of sprint for water, NaCl and NaHCO3, respectively). Both serum total calcium concentration (tCa) and iCa increased (P<0.05) with running. NaHCO3 decreased iCa (P<0.05) compared to water; iCa of 1.58 and 1.44 +/- 0.04 mmol/l before exercise and 1.69 and 1.49 +/- 0.05 end sprint, for water and NaHCO3 treatments, respectively. These results demonstrate an effect of NaHCO3 on iCa during exercise. Further study is necessary to determine the effect of alterations in iCa on exercise performance.

The effect of sodium bicarbonate and validation of beckman coulterAU680 analyzers for measuring total carbon dioxide (TCO2) concentrations in horse serum

“…). During prolonged exercise, lactic acid builds up in the muscle of horses, lowering the blood pH (Beard & Hinchcliff ). A mixture of alkalinizing salts, usually sodium bicarbonate, is given by some trainers in a process called ‘milkshaking’ to increase the blood buffering capacity in order to remove lactate from the skeletal muscle, delaying fatigue (Lloyd & Rose ; Waller et al .…”

“…It has been suggested that such treatment given 3-5 h prior to racing may enhance a horse's racing performance by increasing the blood buffering capacity and enhancing lactate clearance from skeletal muscle, thereby delaying the onset of fatigue (Sutton et al 2014). During prolonged exercise, lactic acid builds up in the muscle of horses, lowering the blood pH (Beard & Hinchcliff 2002). A mixture of alkalinizing salts, usually sodium bicarbonate, is given by some trainers in a process called 'milkshaking' to increase the blood buffering capacity in order to remove lactate from the skeletal muscle, delaying fatigue (Lloyd & Rose 1995;Waller et al 2010).…”