Horse Rhabdomyolysis Prevention: Exercise, Diet and Genetics

Preventing recurrent tying-up in horses requires understanding the genetic basis and implementing tailored exercise and dietary strategies.

Key Facts

Recurrent Exertional Rhabdomyolysis (RER) affects primarily Thoroughbreds and appears linked to calcium regulation abnormalities.
Polysaccharide Storage Myopathy (PSSM1) causes abnormal glycogen storage; dietary management is highly effective.
PSSM2 is a heterogeneous group of myopathies — genetic testing has limited clinical utility compared to PSSM1.
Vitamin E and selenium deficiency can cause nutritional myopathy; blood testing guides supplementation.
Consistent daily exercise patterns reduce RER episodes; sudden increases in workload after rest are a major trigger.
Electrolyte supplementation and warm-up/cool-down protocols are standard management recommendations.

Welfare Considerations

Rhabdomyolysis episodes cause acute, significant pain and distress. Prevention is far preferable to reactive treatment. Management plans must be individualised based on confirmed myopathy subtype — PSSM1 and RER require different dietary and exercise approaches. Owners benefit from clear written protocols for what to do during an episode and how to prevent recurrence. Regular veterinary reassessment ensures protocols remain appropriate as fitness and workload evolve.

What You Can Do

Genetic test horses with recurrent episodes for PSSM1 (GYS1 mutation) to guide dietary management.
Maintain consistent daily work schedules — avoid rest days without compensatory turnout or gentle exercise.
Provide a low-starch, high-fat, high-fibre diet for PSSM1 horses.
Discuss selenium and vitamin E blood testing with your vet for horses with unexplained muscle pain.