Exercise Intolerance in Horses

Recognized when horses are willing but unable to perform in routine training and conditioning
Exercise intolerance is one of the first signs of exhaustion
When persistent and unexplained, exercise intolerance may be a symptom of complicated underlying conditions like muscle disease, arthritis, respiratory illness, heart disease, or any combination of the above
Diagnosing the cause for exercise intolerance requires extensive testing
Veterinarian assistance is required for diagnosing the cause and developing a treatment plan

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A closer look: Exercise Intolerance in Horses

Horses showing consistent exercise intolerance, without improvement over time, have an underlying health condition. Muscle disease and respiratory disorders are common. Some conditions associated with exercise intolerance are easily treatable through a change in diet, supplements, and training. Certain breeds have genetic predisposition, making them more susceptible to muscle disease.

Arthritis is very common in horses, and once developed is a lifelong condition. The goal of treatment in these cases is to slow down the progress of the condition and increase quality of life. Exercise intolerance is associated with heart conditions, which are very rare and unpredictable, but can be fatal.

Possible causes

Exercise intolerance may point to a number of different types of illnesses.

Respiratory illnesses, such as

Paralysis of the larynx

Inflammatory Airway Disease (IAD) in Horses

Exercise-induced pulmonary hemorrhage (EIPH)

Muscle disorders, such as

Myopathies

Exertional Rhabdomyolysis

Laminitis in Horses

Cardiac disorders, such as

Atrial Fibrillation in Horses

Arrhythmias

Musculoskeletal conditions, such as

Arthritis (Osteoarthritis) in Horses High and Low Ringbone (Interphalangeal Joint Arthritis) in Horses Bone Spavin (Distal Hock) Arthritis in Horses Disorders of the Spine in Horses

Risk factors

If caused by extreme exhaustion, exercise intolerance requires immediate vet assistance or the exhaustion can be fatal. Extreme signs of exhaustion in horses include: inability to move, dehydration, shock, colic, and diarrhea. Seek ON SITE veterinary attention IMMEDIATELY. DO NOT MOVE the horse until cleared by a medical team.

Rapid onset of exercise intolerance, within one training session, is most likely exhaustion. Severity and frequency of exhaustion varies with the conditioning of the horse, diet, and environmental factors. Horse owners and trainers need to know the signs of extreme exhaustion as well as the behavior signals of the individual horses they are working with to prevent fatal complications.

Intolerance associated with arthritis varies in severity. Horses can continue competing or be forced to retire early. While treatable, advanced stages of arthritis can cause lameness where euthanasia is the only treatment.