Exercise Induced Pulmonary Hemorrhage (EIPH) in Horses
A comprehensive guide to understanding, detecting, and managing lung bleeding in equine athletes.
Understanding EIPH
Exercise-Induced Pulmonary Hemorrhage (EIPH) isn't new. This condition was first noted in the 1600-1700s within the world of Thoroughbred racing, where speed and power were revered. Those ancient bloodlines, including the hardiness of Arabian horses, now course through many of today's top equine athletes. EIPH primarily occurs in racehorses—Thoroughbreds, Standardbreds, and Quarter Horses—due to the demands of quick acceleration and intense effort.
However, EIPH is also common among other high-performance equine athletes, including those in cutting, reining, barrel racing, roping, polo, cross-country, three-day eventing, show jumping, hunter-jumper, steeplechase, dressage, endurance, and draft pulling. While severity often increases with the intensity and duration of effort, EIPH can even occur at moderate speeds. Ironically, some of the most talented athletes seem to be the ones most affected. This is due to the delicate balance between a horse's powerful heart and relatively modest lungs, making them all susceptible to EIPH.
To understand why EIPH occurs, let's look more closely at the horse's athletic design and what happens when exercise intensity increases. Through selective breeding, horses have developed massive, powerful hearts capable of fueling intense athletic demands. As exercise intensity increases there is a need for increased oxygen intake and distribution to the muscles powering locomotion. To deliver the oxygen heart muscle contractions get stronger and heart rates increase to as high as 220 beats per minute pumping 75 plus gallons of blood through the lungs every minute.
The increased blood volume pumped is intensified by the horse's natural ability to "blood dope"—resulting from splenic contraction—that increases the red blood cell concentration to carry more oxygen. However, this oxygen-rich, thicker blood is harder to pump, leading to exceptionally high blood pressure within the lungs. Blood pressure in horses' lungs can increase four-fold during intensive exercise. Yet while heart and muscle development have prioritized speed and strength, the lungs haven't evolved quite as robustly.
When galloping, horses breathe in approximately two four-gallon buckets (8 gallons) of air every second and nine 55-gallon barrels of air every minute.
Deep within the lungs, the oxygen-containing air that is inhaled through the nose travels to the alveoli where it diffuses across the fragile blood gas barrier (the pulmonary capillary membrane or "PCM") where it binds to the hemoglobin in the red blood cells passing through the small capillaries in the lungs. From these capillaries the blood is carried back to the heart to be pumped throughout the body to the muscles and other tissues that power locomotion.
When galloping, a horse's breathing and stride are linked. With each powerful stride, the horse inhales forcefully creating a vacuum effect to draw in 120-140 breaths per minute. And, because horses are obligate nasal breathers, air can only come in through their nose. The strong vacuum pressure causes the unsupported soft tissue in the nasal passages to partially collapse, increasing airflow resistance. The combination of forceful inhalation with collapsing airways add incrementally to the stress put on the respiratory system, especially as speeds increase.
The pulmonary capillary membrane (PCM) separates the pulmonary capillaries from the alveoli deep within the lungs. The PCM is 1/100th the thickness of a human hair, meaning it's very efficient at transferring oxygen and carbon dioxide in the lungs, but is very fragile.
During intensive exercise the high blood pressure in the lungs pushes outwardly on the PCM from inside the pulmonary capillaries while the high vacuum pressure pulls on the outside of the PCM. The combined stress of the pulling and pushing on the PCM causes it to rupture releasing blood cells into the alveoli resulting in exercise induced pulmonary hemorrhage (EIPH).
Simultaneously, each hoof strike sends vibrations up the limbs and across the shoulder blade, penetrating the chest and placing additional stress on the delicate blood vessels in the lungs. Further adding insult to injury, exercising blood flow is preferentially directed toward the upper and back portions of the lungs, which are particularly susceptible to damage. Over time with repeated episodes, the tiny veins in these regions undergo remodeling, leading to scarring, iron deposits, and thickening of the vessel walls. This narrowing further raises blood pressure in the lungs, compounding the risk of vessel rupture. Together, the combined action of these forces converges on the fragile pulmonary capillary membrane, causing tiny blood vessels to rupture and leak blood into the airways—a condition known as EIPH.
When cardiovascular issues are present, they can exacerbate EIPH. Irregular heart rhythms, such as atrial fibrillation, valve leakage, and insufficient heart muscle relaxation at high exercising heart rates disrupt the filling of heart chambers and can further elevate blood pressure in the lungs. These conditions amplify the stress on lung blood vessels, increasing the likelihood of EIPH and its detrimental impact on a horse's performance and health.
Upper airway conditions that cause upper airway obstruction can also exacerbate EIPH. These include, for example, dorsal displacement of the soft palate (DDSP), laryngeal hemiplegia (LH or "roaring"), soft tissue instability, masses in the upper airways, and rider-induced hyperflexion of the head and neck. These obstructions partially block the airway, reduce its diameter, and create turbulent airflow, forcing horses to work harder to breathe. As obligate nasal breathers with long windpipes, horses already face airflow limitations, and these obstructions further intensify the vacuum effect on the delicate blood vessels, increasing the risk and severity of EIPH. Overground exercise endoscopes may help to identify clinically relevant upper airway obstructions including dorsal displacement of the soft palate and laryngeal hemiplegia.
One of the more challenging aspects of EIPH is that, often, the problem begins insidiously as horses begin their competitive careers. It might be so minor at first that it's hardly noticeable, a minor leak in the delicate lung tissues that doesn't impact performance. But over time, with each strenuous workout or competition, the bleeding can become more frequent and more severe. Effects become cumulative and progressive as the affected portion of the lung continues to move from the back forward, encompassing more and more of the lung. Scar tissue from repeated episodes begins to alter the architecture of the lungs, reducing their elasticity and, ultimately, their efficiency. Large volumes of blood from acute episodes along with scarring and thickening of blood-gas exchange regions can lead to reduced performance and stamina or "exercise intolerance" as impaired gas-exchange from the lungs makes it a struggle for the circulation to deliver enough oxygen to the muscles. For high-level athletes, this early fatigue can mean the difference between winning and falling short.
Inflammation plays both a causative and consequential role in the severity and progression of EIPH. When blood enters the lungs, it doesn't simply disappear; immune cells work to break it down for clearance, but they can become overwhelmed, leaving behind incomplete cleanup and lingering inflammation that worsens bleeding through a vicious cycle of damage. Furthermore, different types and levels of exercise cause differing effects on inflammation and declining immunity of lungs. Exposure to respiratory irritants—such as poor-quality air, airborne pollutants, respiratory viruses, and the dust, molds, and endotoxins found in hay—further inflames the airways. Inflammation, regardless of cause, can lead to mucus buildup that impedes airflow and permanently damages airways, decreases lung compliance, and blunts gas-exchange efficiency, as a result of scarring that heightens the risk of EIPH during future exercise bouts, as well as impairing performance and increasing susceptibility to infections. Treatments targeting inflammation show promise in boosting immunity and delivering anti-inflammatory effects that help break this harmful cycle.
At its core, EIPH is a natural byproduct of the horse's athletic design—a complex physiological adaptive response that can become a disease. Lower levels of EIPH may not have much impact on performance, but for horses that bleed more severely, EIPH can interfere with their endurance, cause early fatigue, and, over time, may shorten their competitive careers. And while it's a sobering diagnosis, there are effective management strategies to support a horse with EIPH, helping to ensure their health, performance, and well-being as they continue to do what they love.
In a way, EIPH reflects the strength and power that fuel our equine athletes. Through knowledge and by protecting lung health—the key limiter of equine performance—owners can make informed decisions to support these extraordinary partners, ensuring they can safely pursue the intense athleticism for which they were born.
Signs of EIPH
Exercise-Induced Pulmonary Hemorrhage (EIPH) can be a hidden problem—its signs aren't always obvious. But don't be misled; EIPH occurs across all levels of athletic performance, even during mild to moderate exercise. It can happen without visible blood at the nostrils or even hide from detection by tracheal endoscopy.
Here's a quick guide to recognizing indicators that may point to EIPH being a problem:
Nosebleeds
Observing a nosebleed is rare. However, if your horse lowers its head to eat or drink, blood may drain from the lungs and become visible at the nostrils.
Swallowing and Coughing After Exercise
Persistent swallowing or coughing post-exercise can indicate blood accumulation in the airways. Your horse may cough to clear the throat or swallow as blood is brought up from the lungs.
Slower Recovery Time After Intense Workouts
An elevated respiratory rate and slow or extended recovery post-exercise may mean the lungs are struggling to provide adequate oxygen. This could indicate an underlying lung issue like EIPH.
Dull or Burnt-Looking Coat Condition
Horses that bleed often exhibit a dull or "burnt" appearance in their hair coat.
Respiratory Distress and Behavioral Changes
Look for signs of respiratory distress, such as raising or tossing the head, extending the neck, and resisting the bit. These behaviors suggest the horse may be trying to increase airflow or alleviate discomfort.
Performance and Competitive Success
Racehorses: Horses with mild EIPH (Grades 1-2) are 4x more likely to win and nearly 2 times more likely to place in the top three than those with moderate to severe EIPH (Grades 2-4). See the discussion below on "Endoscopy" for a detailed discussion of EIPH Grading.
Severe EIPH: Horses with severe EIPH (<15%) are less likely to win or place as a result of the blood negatively impacting performance and may have a shortened career due to cumulative damage to their lungs.
Barrel Racers: EIPH is positively correlated with run speed (i.e. ability) in barrel horses, although severe cases can still impact stamina.
Signs of Exercise Intolerance
Immediate and Long-Term Effects: Severe bleeding episodes cause inflammation and swelling in the lung tissue, often leading to airway obstruction by blood and mucus. Repeated episodes contribute to cumulative lung scarring, progressively involving larger portions of the lungs. Scar tissue thickens the blood-gas barrier, and inflammation fills the airways with blood and mucus, while increased shear stress at the junctions between healthy and scarred tissue further aggravates bleeding. Together, these factors significantly reduce oxygen exchange efficiency and limit exercise tolerance. High inflammation levels can also lower the threshold for lactate accumulation, raise heart rate above 200 beats per minute more quickly, and increase overall lactate concentration—all of which impact athletic performance and hasten fatigue.
Indicators: If your horse suddenly loses focus or speed, stumbles, hits rails, or tires earlier than usual, this could indicate a significant bleed. Reduced lung function and oxygen deficit can lead to muscle fatigue and decreased performance. Common symptoms include stumbling, muscle cramps, and early-onset fatigue.
Rare but Serious: Sudden Death
Though rare, severe cases of EIPH can lead to sudden death.
Understanding these signs and monitoring them closely can help you identify EIPH early and keep track of its progression. Remember, even minimal bleeding can gradually affect lung health and athletic ability over time.
Diagnosing EIPH
When faced with an EIPH diagnosis, understanding the range of diagnostic tools available can help you and your veterinarian assess and manage the condition effectively. Almost all horses experience some degree of lung bleeding during intense exercise. For most, it's mild and may not affect performance. Recognizing EIPH as a common issue in athletic horses can make the diagnosis feel more manageable, though assessing severity is essential.
Here's what to keep in mind:
If your horse is one of the rare (<5%) of horses that have shown blood after exercise, you will want to rule out other causes. If you see blood from the nostrils, confirm its source since nosebleeds can also stem from other issues like trauma, ethmoid hematomas, sinus tumors, or guttural pouch infections. These require different treatments and shouldn't be confused with EIPH.
If your horse is like the majority of horses, they will not show external evidence of bleeding.
The following are currently used diagnostic tools:
Endoscopy
The "Gold Standard" Test: Endoscopy (tracheobronchoscopic examination) involves inserting a small camera into the trachea to check for blood and mucus in the airways. It's best done within 30-120 minutes after exercise to detect bleeding accurately.
Timing is Crucial: Bleeding can be delayed or isolated, sometimes leading to false negatives with endoscopy if not detected in the trachea right away. Using a 3m versus a 1m scope to reach the bronchi and bronchioles improves detection, or repeating the scope three times on different days improves reliability of diagnosis. Also, hemorrhage can occur for up to 20 hours post-exercise.
Grades of EIPH & Inflammation: Your veterinarian may discuss the EIPH grade, as well as inflammation grade (based on mucus), which can guide treatment and management. EIPH is graded 0-4.
Transtracheal Wash and Bronchoalveolar Lavage
Transtracheal Wash (TTW) is a procedure that collects a sample of fluid from a horse's trachea to detect blood or inflammatory cells, helping to confirm lung bleeding and the presence of a secondary bacterial infection. Typically a long plastic catheter is passed through a large needle inserted between the cartilage rings of the trachea and saline is injected from a syringe and then withdrawn back into the syringe for examination.
Bronchioalveolar Lavage (BAL or "Lung Wash") is a procedure that involves washing the lungs of a horse with saline and collecting samples that most accurately assess bleeding severity and level of inflammation by counting red blood cells and white blood cells, respectively, as well as hemosiderophages—immune cell scavengers that are indicative of red blood cell clearance and breakdown from previous episodes. This technique also catches those mild "bleeders" that may be missed by scoping. Typically a tube or small endoscope is passed through the nostrils in the lower airways and saline is flushed in and then sucked back out for examination under a microscope.
BAL is the most sensitive and accurate method for detecting EIPH. There is a weak correlation between the number of red blood cells (RBCs) detected in bronchoalveolar lavage fluid (BALF) and findings from endoscopy. This is because the standard 1-meter endoscopes often used in tracheobronchoscopic examinations often cannot reach the smaller airways of the lungs. Use of a 3-meter endoscope improves the accuracy and sensitivity of endoscopy, especially when performed 30 minutes to 2 hours after exercise.
Imaging Techniques
X-rays, Nuclear Scintigraphy, and Ultrasound: These imaging methods provide non-specific details about lung health and abnormalities. While not definitive for EIPH, they can give a fuller picture of any underlying issues.
Blood Biomarkers
Biomarkers found in the blood such as angiotensin converting enzyme (ACE) that have been associated with EIPH, as well as haptoglobin, secretoglobin, surfactant protein D, and serum amyloid A that are linked to equine asthma, can help detect hemorrhage and inflammation, respectively, adding another layer of understanding to your horse's diagnosis.
Combination of Diagnostic Tests
No single test can capture the full scope of EIPH. Combining diagnostics gives a clearer picture of bleeding severity, inflammatory impact, and the potential of airway obstructions and heart issues to contribute to lung bleeding if they are present. Overground exercise endoscopes may help to identify clinically relevant upper airway obstructions including dorsal displacement of the soft palate and laryngeal hemiplegia that impact airway resistance and thus EIPH. Exercising or immediate post-exercise electrocardiograms can identify atrial fibrillation, a cardiac arrhythmia, that can exacerbate EIPH. Cardiac ultrasound can identify leaky valves and other functional abnormalities that may impact EIPH levels.
The 4 grades of increasing severity found on tracheobronchoscopic examination for EIPH are:
Grade 0: No visible blood in the airways.
Grade 1: Small flecks or short, thin streaks of blood covering less than 10% of the airway surface.
Grade 2: Longer streaks (over half the trachea's length) or multiple short streaks covering less than one-third of the airway.
Grade 3: Multiple streams of blood covering more than one-third.
Grade 4: Blood covers over 90% of the airway and pools at the point where the trachea enters the chest.
By understanding the diagnostic options and working closely with your veterinarian, you can get a well-rounded view of your horse's condition. This comprehensive approach allows for an informed management plan to help your horse perform its best, even with an EIPH diagnosis.
Managing and Treating EIPH
Managing EIPH in horses requires a balanced strategy to reduce both the immediate impact of bleeding and long-term lung health consequences. While there is no cure, certain treatments and management techniques can lessen bleeding frequency and severity, protecting your horse's overall health. It is important to stay informed and continually educate yourself regarding advancing treatment research, and which ones are supported by science. Since EIPH is a complex and multifactorial problem, multimodal treatments considering all of the contributing causes are key and will provide the greatest success. Managing EIPH is quintessential since the lungs are the limiting factor in performance.
Recognize that all EIPH treatments have efficacy limitations. None are curative. Management of EIPH focuses on reducing severity rather than complete prevention.
There is no currently known means to "stop" EIPH. Because EIPH is multifactorial it is reasonable that a multimodal approach tailored to your horse's needs and competition demands, is typically most effective. Use treatments proven by research to avoid interfering with overall therapy. When needed, many of the antibiotics, corticosteroids, and bronchodilators can be administered via inhalation. Investing in a proven nebulizer will allow safe nebulization of medications and prevent unwanted side effects due to systemic exposure. It is also important to know which medications and treatments negatively interact.
When considering treatment, regulatory rules must be considered. Some medications may be restricted in races or shows. Always check competition regulations to avoid disqualification or penalties.
The following is an overview of treatment options to discuss with your veterinarian. It should be noted that some are for reducing the severity of EIPH during exercise, some for treating the acute impact of EIPH, some for healing, and some are beneficial for overall lung health care. Proper management and a healthy respiratory system are key to reducing EIPH.
Reducing EIPH During Exercise
FLAIR® Equine Nasal Strips
Non-Pharmacological Option: FLAIR Equine Nasal strips are the only non-drug solution proven to reduce EIPH severity. The Strips work by reducing inspiratory airway resistance commensurate with the exponential increase in resistance normally seen as the exercise intensity increases, and this effect parallels the decrease in pressure across the fragile pulmonary capillary membrane, lessening EIPH severity. In essence FLAIR Strips have a proportionately greater impact on EIPH reduction as exercise intensity increases. Studies show the Strips are equally or even more effective than Lasix™ during maximum exercise efforts, making them a suitable choice in competitions as an alternative to or in addition to Lasix.
Performance Optimization: Decreased airway resistance reduces the effort to breathe and therefore the oxygenated blood required for the muscles of inspiration, thus sparing and diverting blood flow to the muscles of locomotion which increases exercise tolerance.
Approved for Competition: FLAIR Nasal Strips are approved for use in flat- and harness-racing within North America. FLAIR Strips have been approved for use by all key non-racing regulatory bodies, including the Federation Equestrian International, the American Horse Shows Association, the National Reining Association, the United States Equestrian Team, the United States Polo Association, the National Barrel Horse Association, and the American Quarter Horse Association. In the international market, FLAIR Strips have been approved for racing in: Mexico, Brazil, Canada, South Africa, New Zealand, Australia, Trinidad, Barbados, Jamaica, the Netherlands, United Arab Emirates, Qatar, Bahrain, Saudi Arabia, India, Korea, Singapore and other countries. FLAIR Strips are also approved by most international sport horse regulatory bodies.
Lasix™ (Furosemide)
Reducing Lung Blood Pressure: Lasix, a diuretic, is the only medication proven to reduce EIPH severity by reducing blood volume through diuretic effects, thus lowering lung blood pressure. NSAIDs dampen or block the Lasix-induced reduction in lung blood pressure, and this is important since many performance horses are taking NSAIDs for musculoskeletal problems.
Secondary benefits: These include redistribution of exercising blood flow within the lung to protect against EIPH and may have bronchodilatory effects. Lasix has performance enhancing effects including alkalinizing effect on the blood to counter lactic acid build up and weight loss which culminate in improved race times and ward off fatigue.
Side Effects: Lasix has side effects, such as dehydration (potential colic issues) and electrolyte imbalance, and effectiveness diminishes over time with long-term repeated use.
Consider Electrolyte Replenishment: Use specially formulated electrolytes for horses on Lasix.
Some events may restrict Lasix use, so consult with your vet on its pros, cons, and alternatives.
Supportive Supplements
Vitamin C and Bioflavonoids: These support capillary stability and immune health, potentially strengthening lung tissues.
Herbal Formulations: Some claim to offer anti-inflammatory or bronchodilator effects but should be used under veterinary supervision.
Caution with Other Medications: Current evidence supporting Aminocaproic Acid & Conjugated Estrogens for reduction of lung bleeding is not strong, with possible negative performance effects occurring with aminocaproic acid. Erectile dysfunction medications with the secondary effect of reducing pulmonary hypertension have not been proven beneficial thus far in reducing EIPH. While some EIPH supplements on the market claim that Vitamin K provides benefit for horses with EIPH, there is no evidence or study that supports this claim. Vitamin K is beneficial to help blood coagulation but blood coagulation has not been shown to be a factor for horses experiencing EIPH.
Therapeutic Considerations After EIPH Diagnosis
Effectively managing EIPH involves a combination of rest, environment control, diet, training adjustments, and collaboration with your vet and barn team.
Here's a straightforward guide:
Infection Control with Antibiotics
Preventing Secondary Infections: Blood in the lungs can lead to infections, so antibiotics are sometimes used as a precautionary measure.
Regenerative Therapies
Healing and Reducing Scarring: Platelet-rich plasma (PRP), amnion-based treatments, concentrated equine serum, and possibly other regenerative biologicals, modulate excessive inflammation to support quicker transition to the reparative phase of tissue repair with less scarring.
Avoid Adult Stem Cells: Risk of tumor or calcification formation.
Compatible Treatments: Hyperbaric oxygen therapy can enhance regenerative treatments, but corticosteroids may interfere and negatively impact healing.
Bronchodilators & Corticosteroids
Improving Lung Function: Medications like clenbuterol and albuterol help dilate airways, making it easier for blood removal after an episode and for corticosteroids to reach inflamed areas and slow scar tissue formation when infection is no longer a concern.
Administer with Corticosteroids: Bronchodilators should be used with corticosteroids to avoid receptor downregulation.
Inhalation Benefits: Inhaled medications minimize systemic side effects, focusing on local effects in the lungs.
Non-Steroidal Anti-inflammatory drugs (NSAIDs): Not typically effective for lung inflammation.
Stall Rest & Controlled Exercise
Rest Period: Following an EIPH episode, a three-week period of stall rest aids lung healing, followed by a gradual reintroduction to exercise over the next eight weeks. A hemorrhage is considered substantial if hemosiderophages—scavenger cells clearing blood—exceed 25%, which typically returns to baseline within four weeks. A follow-up BAL to confirm recovery may help reduce the risk of severe EIPH upon returning to work.
Extended Rest if Needed: If EIPH recurs, increase stall rest to four weeks, followed by pasture turnout, with a possible six-month layup.
Why It Works: Limiting activity reduces further lung damage and allows inflammation to subside.
Items 5-8 below are recommended here to improve recovery after EIPH; however, it should be noted that these recommendations should be part of any equine management program to enhance general respiratory health and reduce the likelihood and severity of lower airway inflammation that contributes to EIPH.
Environmental Control
Reduce Irritants: Dust, mold, and ammonia irritate the respiratory tract and worsen EIPH. Opt for dust-free bedding, such as wood pellets, coarse shavings, cardboard, or paper versus sawdust or straw.
Barn Tips: Avoid storing hay over stalls and keep barn sweeping and the use of fans and leaf blowers to a minimum. Move horses outside before arena work starts.
Ventilation: Maximize pasture turnout and ensure the stable has optimal ventilation.
Travel: Before travel, ensure your horse's vaccinations are up-to-date and practice good biosecurity at shows to avoid exposure to respiratory viruses that lead to increased inflammation in the lungs.
Healthy Diet
Omega-3s for Inflammation: Adequate doses of omega-3 fatty acids (DHA and EPA) can reduce lung inflammation and improve red blood cell flexibility, aiding their passage through the lungs' small blood vessels. A three-month loading period is required for optimal effect. Avoid flaxseed, as horses cannot convert it effectively.
Dust-Free Forage: Steam hay to reduce dust and bacteria while preserving nutrients. If soaking hay, limit it to 30 minutes to prevent nutrient loss and bacterial growth, or consider feeding a complete pelleted diet instead.
Avoid Round Bales: Round bales tend to produce dust and mold, which can worsen respiratory conditions.
Training Adjustments
Build Gradually & Strategize: Training represents about 90% of a horse's career, making it a critical factor in managing EIPH-related lung damage. While the damage from training is generally milder than that from competition, it accounts for the majority of cumulative lung damage and is directly proportional to the duration of training. By focusing on gradual and strategic training, you can build a solid fitness foundation while lowering the risk of EIPH.
Emphasize Endurance and Stamina: Begin with low-speed stamina work (walk, trot, canter) and gradually increase the workload. This helps build foundational fitness and reduces lung strain. High-intensity exercises like galloping or sprinting should be introduced only after the horse achieves this base fitness, and the frequency should align with the specific athletic discipline.
Monitor Heart Rate: Use heart rate monitors to ensure the horse stays below 150 bpm, which indicates the aerobic training zone. Staying within this range keeps airway and lung blood pressure manageable, reducing the risk of EIPH.
Tools To Increase Workload: To increase workload without speed, consider using water resistance (10–30 cm depth), hill work, underwater treadmills, swimming, extra weight, extended walk/trot sessions, cavaletti exercises, and small circles. Note that some of these can intensify bleeding if used at high intensities.
Avoid Rapid Acceleration Events: Activities like sprint racing and barrel racing can quickly spike lung blood pressure in the lungs, increasing the risk of severe bleeding. Limit these events and follow with adequate rest and recovery.
Plan for Recovery and Tapering: Avoid intense workouts on consecutive days. Alternating work and rest days across the week is ideal. Include rest days between hard sessions to allow lung tissue to recover. Additionally, taper the workload 3–7 days before competitions to support tissue repair and minimize bleeding risk.
Return to Work Gradually After Layoffs: After an EIPH episode or a break in training, ease the horse back into work. For breaks under a month, a 7–10-day gradual return is sufficient; for longer layoffs, reintroduce work progressively over a period equal to the duration of time off.
Structure Weekly Training: Aim for 3–4 days of cardiovascular (aerobic) training weekly to build fitness and maintain with 1–2 days per week. Limit session durations to 45–60 minutes. For strength and speed work, plan 2–3 days per week for gains, backing off to 1 day weekly for maintenance, using interval training as a safer option.
Incorporate Inspiratory Muscle Training: Consider using a mask with valve-controlled resistance to strengthen respiratory muscles. This can improve lung function while reducing strain.
By combining knowledge with smart exercise strategies, you can get your horse fit and competition-ready while minimizing the risk of bleeding associated with EIPH.
Minimize Risk Factors: Avoid hard ground, excessive frequency or duration of intense workouts, and situations that add strain, such as training obese horses, using heavy riders, and moderate- to high-impact activities (e.g., steeplechase, hurdling, and high-level jumping). Cold-air exercise (below 20°C) can also worsen EIPH. Consider tack adjustments, like bits and headgear, to reduce upper airway obstructions, and avoid training in extreme heat, which exacerbates airway inflammation.
Strategic Use of Treatments During Training: Apply treatment strategies not only during competition but also in training to prevent persistent inflammation and cumulative lung damage, extending the horse's athletic career. Racehorses are three times more likely to bleed without Lasix. Plan training sessions so that a single dose of Lasix, paired with controlled water intake, may cover two sessions, as its effects can last beyond 24 hours. Since Lasix is particularly effective in reducing EIPH during fast acceleration or sprint-type exercises, reserve its use for these sessions to minimize side effects and reduced efficacy with repeated long-term use. Utilize FLAIR Strips for both sprint and endurance workouts, as they effectively reduce bleeding with both types of exercise and without side effects. Maintain continuous use of immunomodulating interventions to help control inflammation.
Adjust Competitive Schedule
Extend Intervals: Prioritize lung health by allowing more time between competitions or races, focusing on gradual fitness gains rather than immediate performance boosts. Whenever possible, avoid high-dust environments like indoor arenas and avoid overloading the competition schedule. Travel thoughtfully by taking regular breaks to let the horse drink and lower its head to clear dust and debris from the lungs, helping to prevent inflammation. Although competition makes up only about 10% of a horse's career, it's often where the most severe lung damage occurs.
Long-Term Benefits: A more spaced-out schedule reduces the recurrence of EIPH, supports lung recovery, and helps sustain performance over the long term.
Partner With Your Vet
Each of these therapeutic modalities supports a multimodal approach to improve lung health, reduce EIPH severity, and extend your horse's competitive career. Regular veterinary checkups can help you monitor EIPH progression, manage inflammation, and adjust treatments as your horse's needs evolve.
Work with Your Vet for Regular Monitoring
Routine Check-Ups: EIPH can worsen over time, so regular vet visits help track any progression and adjust treatment as needed.
Catch Changes Early: Ongoing monitoring lets you adapt management strategies to meet your horse's changing needs. Keep a training and competition journal for accurate documentation.
Embrace a Team Approach
Coordination Matters: Working closely with your vet, trainers, and barn staff ensures that everyone is aligned on the best practices for supporting your horse's health and performance.
While EIPH cannot be prevented, these management steps, combined with professional support, can help protect your horse's lung health, manage symptoms, and extend their athletic career.
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