Exercise-Induced Pulmonary Hemorrhage In Horses

EIPH or Exercise-induced pulmonary hemorrhage is common in Thoroughbreds and Standardbreds, especially those that race. It is bleeding, or epistaxis, from the nasal passages following extreme exertion. The bleeding may be accompanied by loud breathing, choking or excessive swallowing. According to Wag!, equines that suffer from bleeding airways may also show signs of distress. [1]

What Causes Equine Bleeding Attacks?

Possible causes include high lung blood pressures during intense exercise, lung inflammation, and shear forces within the chest generated during exercise. Research is ongoing, and the condition is likely due to multiple factors. – Merck Veterinary Manual. [2] Finding lesions in the lungs of EIPH horses may indicate that this condition is a disease rather than a result of extreme exercise. The possibility of it being a progressive disease is there but again, more research is needed for confirmation.[3]

Are Racehorses the Only Equines That Bleed After Running?

EIPH is a condition commonly found in the racing industry, however, bleeders can be found in other equine sports. Disciplines that require short but strenuous exertion such as polo, show jumping, barrel racing and eventing can also rupture the capillaries in the lungs releasing blood into the airways.

Veterinary Diagnosis Options

Not all equines will have bloody noses or blood-tinged mucus that drips from one of both nostrils. When the vet scopes your horse, they may only find blood within the lungs or airways. Only proper examination can determine if the bleeding is caused by exercise-induced pulmonary hemorrhage or another condition. Diagnostic tools helpful for confirming the cause of bleeding in equine lungs and airways: Endoscopic exam – Camera passed through the nose into the airways immediately after exercise Bronchial-alveolar lavage (BAL) fluid examination – Saline wash of the airways and air sacs to collect a fluid sample Trans-tracheal wash (TTW) fluid examination: An aseptic airway wash to collect fluids for in-depth cytological, culture and sensitivity testing. (done under sedation) Radiography, pulmonary scintigraphy and lung function tests – Used to eliminate other respiratory conditions that may be causing poor performance[4]

Recommended Treatment

Once a proper diagnosis is made, your veterinarian will decide what medication, if any, is needed for your bleeder. Medications such as furosemide, bronchodilators and corticosteroids may reduce the severity of the hemorrhagic episodes but may not stop the bleeding completely. [5] Complete recovery from a bleeding episode may take four to six weeks. In many states and countries a horse cannot race for at least 10 days after a bleeding episode. – EquiMed [6]

Bleeder EIPH Horse Supplements

Having a horse come out of the ring or off the track with a bloody nose can be unsettling. While we can’t cure EIPH, TWYDIL USA does offer a respiratory supplement intended to minimize oxidative stress and reduce inflammation. TWYDIL X is a proprietary formula created to provide essential support to the lungs and blood vessels. It helps reduce airway bleeding and promotes the recovery of lungs damaged by EIPH related episodes. Our all-natural respiratory aid meets international anti-doping requirements and is safe to use before, during and after competition. It can also be used as daily maintenance in horses with exercise-induced pulmonary bleeds as well as other respiratory conditions.


  1. “Exercise-Induced Pulmonary Hemorrhage in Horses”. Wag!. Web. Retrieved Jan. 22, 2021 from https://wagwalking.com/horse/condition/exercise-induced-pulmonary-hemorrhage-
  2. Rush, Bonnie R. DVM, MS, DACVIM. “Exercise-Induced Pulmonary Hemorrhage in Horses.” Merck Veterinary Manual, May 2019. Web. Retrieved Jan. 22, 2021, from https://www.merckvetmanual.com/horse-owners/lung-and-airway-disorders-of-horses/exercise-induced-pulmonary-hemorrhage-in-horses
  3. “Exercise Induced Pulmonary Hemorrhage in Horses: American College of Veterinary Internal Medicine Consensus Statement”. Journal of Internal Veterinary Medicine, May 2015. PMC – PubMed Central. Web. Retrieved Jan. 23, 2021 from  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895427/ 
  4. Groenendyk, Jane, BVSC (HONS) BSC. “Exercise-induced Pulmonary Hemorrhage”. Horses and People. Web. Retrieved Jan. 23, 2021 from https://horsesandpeople.com.au/exercise-induced-pulmonary-hemorrhage/ 
  5. Groenendyk, Jane, BVSC (HONS) BSC. “Exercise-induced Pulmonary Hemorrhage”. Horses and People. Web. Retrieved Jan. 23, 2021 from https://horsesandpeople.com.au/exercise-induced-pulmonary-hemorrhage/ 
  6. EquiMed Staff. “Exercise-Induced Pulmonary Hemorrhage – Equine Diseases & Conditions. EquiMed, July 21, 2014. Web. Retrieved Jan. 23, 2021, from https://equimed.com/diseases-and-conditions/reference/exercise-induced-pulmonary-hemorrhage