Tracing Acid-Base Variables in Exercising Horses: Effects of Pre-Loading Oral Electrolytes.
Authors: Waller Amanda P, Lindinger Michael I
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Prolonged moderate-intensity exercise typically induces a mild alkalosis in horses, but pre-exercise oral electrolyte administration may modulate this response through enhanced fluid and electrolyte absorption. Waller and Lindinger administered four horses with either 3 L or 8 L of a hypotonic electrolyte solution, or water alone, one hour before treadmill exercise at intensities ranging from 35–50% peak VO₂, sampling blood at 10-minute intervals to track acid-base dynamics including hydrogen ion concentration [H+], total CO₂ (TCO₂), partial CO₂ pressure (pCO₂), and strong ion difference (SID). The 8 L electrolyte treatment successfully maintained plasma [H+] and prevented the expected alkalotic shift during moderate exercise, whilst reducing TCO₂ to a nadir of 28.0 ± 1.5 mmol/L; the smaller 3 L dose produced minimal effects at low exercise intensities. For practitioners managing horses undergoing sustained moderate work, this finding suggests that strategic pre-exercise electrolyte loading at volumes sufficient to fully replace anticipated sweat losses may help buffer the acid-base perturbations of prolonged exertion, though individual sweat rates and exercise duration will determine the practical dose required for each animal.
Read the full abstract on PubMed
Practical Takeaways
- •Pre-exercise electrolyte loading at 8 L can help mitigate the mild alkalosis that normally occurs during moderate intensity endurance work, potentially supporting performance
- •Smaller electrolyte supplementation volumes (3 L) are unlikely to meaningfully alter acid-base status, suggesting dose-response matters for this intervention
- •Electrolyte composition and hypotonic delivery may be more effective than water alone for managing acid-base state during prolonged exercise
Key Findings
- •8 L pre-exercise electrolyte supplementation maintained plasma [H+] during moderate intensity exercise, whereas water alone resulted in decreased [H+]
- •8 L electrolyte supplementation decreased plasma TCO2 to 28.0 ± 1.5 mmol/L by early exercise period
- •Plasma pCO2 and strong ion difference [SID] were primary drivers of acid-base changes, not [H+] alone
- •3 L electrolyte supplementation had minimal effects on acid-base variables during low intensity exercise