Horse Electrolyte Imbalance in Work and Heat

Electrolyte imbalances in horses during exercise and heat are a significant welfare and health concern requiring proactive management.

Key Facts

Horses lose sodium, chloride, potassium, and magnesium through sweat, particularly during intense exercise or in hot weather
Signs of electrolyte depletion include reduced performance, muscle cramping, thumps (synchronous diaphragmatic flutter), and altered mentation
Thumps in horses is a specific electrolyte-linked condition involving involuntary diaphragmatic contractions
Electrolyte supplementation should be paired with access to clean water to prevent hypernatraemia
Salt blocks alone are insufficient for horses in heavy work — targeted electrolyte pastes or powders are often necessary

Welfare Considerations

Electrolyte imbalances cause muscle pain, weakness, and in severe cases neurological signs that represent acute suffering. Horses at endurance events or during hot-weather competitions are particularly at risk. Effective electrolyte management requires understanding individual sweat rates and tailoring supplementation accordingly, not simply providing salt blocks.

What You Can Do

Provide free-choice salt and ensure excellent hydration before, during, and after strenuous exercise
Administer electrolyte supplements appropriate to your horse's workload and environment
Monitor for signs of thumps, muscle stiffness, or reduced drinking during hot weather
Consult your vet to develop a personalised electrolyte plan for horses in demanding disciplines