tying up

“Tying up” or exertional rhabdomyolysis refers to muscle stiffness and pain after exercise. Other muscle metabolism problems can also occur, but the clinical signs are often the same, resulting in muscle cramping.


There are two sub-types of “tying-up”:                                                                                                                          1. Sporadic (acute or one-off)                                                                                                                                        • Due to a temporary problem in muscle cells caused by fatigue, heat exhaustion or electrolyte imbalance                        • Can happen in any breed                                                                                                                                          2. Chronic/Recurrent                                                                                                                                                   • Genetic/inherited problem with the way muscles use calcium                                                                                       • Seen in thoroughbreds, Arabians and Standardbreds which can be due to genetic                                                         • Occasionally the cause is unknown

Clinical Signs:        

The range of clinical signs associated with tying up can change depending on how badly the horse is affected. The signs of “tying up” can range from mild to severe and include the following, all associated with exercise:                                         • Firm and painful muscles over the loin and croup                                                                                                        • Excessive sweating                                                                                                                                                 • Quick, shallow breathing                                                                                                                                           • Increased heart rate                                                                                                                                                  • Muscle tremors                                                                                                                                                       • Reluctance or refusal to move                                                                                                                                    • Reddish-brown colored urine (severe)                                                                                                                          • Lying down/inability to rise (can mimic colic)                                  

Exercise should be stopped immediately and a veterinarian called if any of the above signs occur. Severe cases that are left untreated can lead to dehydration and increase the chance of kidney damage due to protein accumulation. Usually horses that tie-up are prone to recurrent episodes.


Extreme cases are not hard to diagnosis physically, but mild cases with decreased performance or hind limb lameness can be confirmed with a blood test that indicates increased muscle enzymes (CK and AST).


Tying-up episodes can be treated through prompt veterinary care, with the administration of an anti-inflammatory or even sedative, followed by rest. Chronic cases can receive intravenous injections of Thiamine or intramuscular Vitamin E and Selenium to decrease potential onset, or can be managed with diet (see below). Unfortunately, there is no cure at the moment.


The recommended diet for a horse with recurrent “tying up” has less starch and more fat, which can be accomplished a number of ways. First, make sure the horse receives 1.5 – 2.0% of his body weight in forage daily. Then, replace some or all of his grain/sweet feed with a commercial product specifically developed with fewer nonstructural carbohydrates. Depending on the product used, additional fat in the form of rice bran, oil, or powder may be necessary. In addition, electrolytes are mixtures containing sodium, potassium, and chloride for horses in heavy training/competition or in hot, humid climates.

We recommend Twydil Electrolytes + C or Protect Plus.