Free Swimming and Exercise-Induced Pulmonary Hemorrhage in Endurance Horses: A Preliminary Study.
Authors: Vinardell Tatiana, David Florent, Galezowski Angelica M, Ali Mohammad, Qasim Muhammad, Massie Shannon L, McCrae Persephone, Filho Silvio, Leguillette Renaud
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Free Swimming and Exercise-Induced Pulmonary Hemorrhage in Endurance Horses Whilst tethered swimming is commonly employed for musculoskeletal rehabilitation and conditioning, anecdotal concerns about exercise-induced pulmonary haemorrhage (EIPH) and subsequent epistaxis have limited its uptake in some equine practices. Vinardell and colleagues conducted a prospective observational study in 15 endurance horses, performing tracheobronchoscopic examination and bronchoalveolar lavage (BAL) following intensive free-swimming sessions (5 × 70 m repeats) to assess whether EIPH occurred. Post-exercise endoscopy revealed only low-grade mucus accumulation with no visible tracheal bleeding, and crucially, BAL fluid analysis showed median red blood cell counts of 271 cells/µL—substantially below the established diagnostic threshold of >1,000 cells/µL for EIPH. These findings suggest that free swimming, at least in the intensities and formats tested, does not trigger clinically significant pulmonary haemorrhage in endurance-trained horses, potentially opening the door to safer confidence in prescribing this modality for conditioning and rehabilitation without the feared complications. Farriers and equine practitioners working with performance horses should note this distinction between free and tethered swimming, though further investigation into tethered systems and other exercise intensities remains warranted.
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Practical Takeaways
- •Free swimming appears safe for endurance horse conditioning and rehabilitation without risk of EIPH under typical training protocols
- •Concerns about tethered swimming causing epistaxis may be specific to that method rather than swimming exercise itself
- •Practitioners can confidently recommend free-swimming sessions for fitness conditioning and musculoskeletal rehabilitation without EIPH concerns
Key Findings
- •Free swimming (5 × 70m sessions) in 15 endurance horses did not induce EIPH, with median RBC count of 271 cells/μL, well below the EIPH diagnostic threshold of >1,000 cells/μL
- •Tracheo-bronchoscopic evaluation revealed only low-grade mucus scores with no tracheal blood observed post-swimming
- •Bronchoalveolar lavage fluid analysis showed low cellularity, indicating minimal pulmonary inflammation or hemorrhage following free-swimming exercise