Horse respiration explained: Recognizing and dealing with respiratory problems

How does horse respiration work?

Horses are obligate nasal breathers, meaning they breathe exclusively through their nose and not through their mouth. Respiration occurs in two phases:

• Inhalation: Air flows through the nostrils into the trachea, passes through the larynx, and reaches the lungs. The oxygen exchange takes place in the alveoli.
• Exhalation: The horse expels used air containing carbon dioxide by contracting the diaphragm and respiratory muscles.

Respiration is closely tied to movement, particularly in canter, where a horse takes one breath per stride. Unrestricted breathing is crucial for maintaining optimal oxygen intake and overall health.

The respiratory system of the horse

The horse's respiratory system can be divided into two areas:

• Upper respiratory tract: This includes the nostrils, nasal cavity, paranasal sinuses, and larynx. The inhaled air is filtered and humidified here before it enters the lower respiratory tract. During intensive breathing, the nostrils can expand - a process known as flaring of the nostrils.
• Lower respiratory tract: This includes the trachea, bronchi, bronchioles, and alveoli. The important gas exchange takes place in the alveoli. The horse has an enormous lung volume, which enables effective oxygen uptake - essential for its performance.

Gas exchange is a central process in which oxygen is transferred into the blood and carbon dioxide is exhaled. Efficient breathing ensures that the horse receives sufficient oxygen for cell function and energy metabolism.

Normal horse respiration rate and deviations

The normal horse respiration rate at rest is around 10 to 18 breaths per minute. Under stress, the breathing rate can increase to up to 240 breaths per minute. Breed variations exist, with Icelandic horses, for example, sometimes displaying a slightly different baseline respiratory rate.

What does the respiratory rate say?

Deviations from the normal breathing rate can indicate health problems. An increased respiratory rate at rest can indicate pain, stress, or respiratory disease, for example. Horse owners should therefore regularly check their horse's breathing rate by observing the movements of the chest or flanks and counting the number of breaths per minute.

Abdominal Breathing in Horses

Abdominal breathing refers to the increased use of the abdominal muscles during respiration, particularly during exhalation. Normally, breathing is primarily controlled by the diaphragm, but when a horse experiences respiratory difficulties, it must engage its abdominal muscles to push air out of the lungs. This results in a visible movement of the flanks and, in severe cases, can lead to the development of a heave line—a pronounced groove along the abdominal muscles caused by chronic respiratory strain.

Abdominal breathing often occurs when airflow is restricted, whether due to poor stable air quality, high dust exposure, or impaired lung function.

Common Respiratory Diseases in Horses

Equine Asthma

Equine asthma is a chronic, non-infectious respiratory disease triggered by allergic reactions to dust, mold spores, or ammonia fumes in stable air. It was previously classified as IAD (Inflammatory Airway Disease) for milder cases and RAO (Recurrent Airway Obstruction, formerly known as heaves) for more severe cases.

Infectious Bronchitis in Horses

Infectious bronchitis is an inflammation of the bronchial tubes, caused by viruses or bacteria. Affected horses often exhibit coughing, fever, and nasal discharge. The disease can spread rapidly, especially in barns with multiple horses. Early treatment and improving stable hygiene are key to preventing further infections.

Pneumonia (Lung Inflammation) in Horses

Pneumonia is a serious condition caused by bacteria, viruses, or fungi. Typical symptoms include high fever, labored breathing, coughing, and general weakness. If left untreated, pneumonia can become life-threatening, so immediate veterinary consultation is necessary if symptoms appear.

Laryngeal Hemiplegia (Roaring) in Horses

Laryngeal hemiplegia, commonly known as roaring, is a paralysis of the laryngeal muscles that leads to whistling or roaring breathing sounds. It is most frequently seen in larger horse breeds and can severely impact performance as it restricts airflow during exertion.

Hay Dust Allergy (RAO) – Chronic Respiratory Disease in Horses

Recurrent Airway Obstruction (RAO), formerly known as heaves, is a chronic respiratory disease triggered by allergic reactions to dust particles from hay and straw. Horses with RAO struggle to exhale, leading to pronounced abdominal breathing and the development of a heave line along the flanks.

A dust-free environment and optimized feeding management are essential for treatment.

Sinusitis in Horses – Inflammation of the Sinuses

Sinusitis is an inflammation of the paranasal sinuses, usually following an infection. Common symptoms include unilateral nasal discharge, facial swelling, and bad breath. Early veterinary treatment is necessary to prevent chronic sinusitis and possible complications.

EIPH (Exercise-Induced Pulmonary Hemorrhage) – Lung Bleeding in Horses

EIPH occurs primarily in high-performance horses and is characterized by bleeding in the lungs. The most common symptom is nosebleeds following intense exertion. While the exact cause remains unclear, training adjustments and targeted medical management can help control symptoms.

Respiratory Problems in Horses: Symptoms and Causes

Symptoms of Respiratory Problems

• Increased respiratory rate: Faster breathing than usual, even at rest.
• Coughing: Especially after exercise or in dusty environments.
• Nasal discharge: Clear or mucus-filled secretions, often with nostril flaring.
• Labored breathing: Visible effort in breathing, possibly with sunken flanks.
• Abdominal breathing: A sign of chronic respiratory distress.
• Decreased performance: Horses may tire quickly and struggle with physical exertion.

If these symptoms appear, consult a vet immediately for diagnosis and treatment.

Common Causes of Respiratory Issues

Helping a Horse with Respiratory Problems

In case of acute breathing difficulties, the horse should be immediately moved to a calm, well-ventilated area.

• Relieve pressure on the neck and chest by loosening the girth.
• Keep the horse calm to prevent further respiratory distress.
• Monitor the breathing rate and movements closely.

If the horse shows signs of shortness of breath or pronounced abdominal breathing, it is advisable to consult a veterinarian immediately.

Preventing Respiratory Diseases

Good air quality and a low-dust environment are essential for maintaining a horse's respiratory health. Dust, mold, and poor stable hygiene can contribute to respiratory issues. By implementing targeted management strategies in housing, feeding, and stable maintenance, the risk of respiratory diseases can be significantly reduced.

Feeding for Lung Support

Healthy lungs are crucial for a horse’s performance, as the body cannot efficiently produce energy without sufficient oxygen intake. Poor respiratory health can affect muscle function, stamina, and overall fitness.

How Can Feeding Support a Horse’s Lung Health?

• Dust-free, high-quality roughage (steamed or soaked hay) helps reduce exposure to mold spores and dust particles.
• Omega-3 fatty acids from flaxseeds or hemp oil have anti-inflammatory properties and can support respiratory health.
• Antioxidants such as vitamins C and E promote lung cell regeneration and strengthen the immune system.
• Herbs like marshmallow root, thyme, and licorice root have expectorant and soothing effects on the airways.
• Minerals such as magnesium and zinc support respiratory function and immune defense.

By ensuring proper nutrition and a dust-free environment, a horse’s lungs can be optimally supported, improving respiratory quality and overall well-being.

Proper Stable Hygiene

Maintaining good stable hygiene is key to preventing respiratory diseases.

Optimal Ventilation in the Stable

• The stable should be well-ventilated but free from drafts.
• Ammonia fumes from urine can irritate the airways; regular cleaning reduces exposure.
• Air quality can be improved through open windows, high ceilings, or ventilation systems.

Using Low-Dust Bedding

• Straw is often dusty and prone to mold, especially if stored improperly.
• Alternatives such as dust-free wood shavings, flax straw, or hemp bedding are better for respiratory health.
• The stall should be cleaned thoroughly every day to reduce ammonia buildup.

Cleaning Aisles and Training Areas

• Avoid dry sweeping, as it stirs up dust. Instead, dampen floors before sweeping or use a vacuum system.
• Riding arena surfaces should be watered regularly to minimize dust.

Ensuring Plenty of Fresh Air and Movement

• Daily turnout or exercise provides access to fresh air and supports lung function.
• Horses kept in stables have a higher risk of respiratory diseases, so regular movement outside the stall is essential.

Inhalation Therapies for Respiratory Support

Inhalation therapies, particularly salt inhalation, have proven to be an effective method for supporting a horse’s respiratory system. This treatment helps loosen mucus and facilitates easier breathing. For chronic respiratory diseases, regular inhalation therapy can aid the healing process and improve the horse’s overall well-being.

The Role of Muscles and the Girth

A horse’s breathing capacity can be affected by external factors such as a tight girth or muscular tension.

• An overly tight girth can restrict the ribcage and make breathing more difficult. Ensuring the girth is adjusted loosely enough allows for unrestricted breathing.
• Muscle tension can also limit respiratory movement. Regular massages and physiotherapy help to relieve tension and optimize breathing efficiency.

Horse Respiration: Frequently Asked Questions

Why is my horse breathing so fast?

Rapid breathing in horses can have various causes, including physical exertion, heat, stress, or underlying health conditions. If a horse consistently breathes faster than 16 breaths per minute at rest, this could indicaterespiratory disease , pain, or circulatory issues. In such cases, a veterinarian should be consulted.

What should I do if my horse is struggling to breathe?

If your horse is experiencing difficulty breathing, follow these steps:

1. Move the horse to a calm, well-ventilated environment.
2. Loosen the girth to relieve pressure on the chest.
3. Observe the breathing pattern and frequency.
4. If signs of shortness of breath or labored breathing persist, consult a veterinarian immediately.

What is abdominal breathing in horses, and how can I recognize it?

Abdominal breathing occurs when a horse has difficulty breathing normally and relies more on its abdominal muscles to assist respiration. This can indicate breathing distress or chronic respiratory disease.

Signs of abdominal breathing include:

• Visible outward movement of the abdomen during respiration.
• Increased effort in the flank region when exhaling.
• In severe cases, the development of a heave line, a visible indentation along the abdominal muscles.

Why is my horse showing abdominal breathing?

Abdominal breathing develops when a horse struggles to breathe efficiently. The abdominal muscles compensate to help push air out of the lungs. This can be caused by:

• Chronic respiratory diseases (such as equine asthma or recurrent airway obstruction)
• Allergies
• Infections
• Environmental factors such as dust or poor air quality

What can I do if my horse has abdominal breathing?

If your horse shows signs of abdominal breathing, take the following actions:

• Consult a veterinarian to determine the exact cause.
• Ensure a dust-free environment by using steamed hay and proper stable ventilation.
• Move the horse outdoors into fresh air whenever possible.
• Loosen the girth to reduce pressure on the chest.
• Adjust feeding practices by offering moistened or steamed hay to minimize dust exposure.

Why is my horse breathing so fast, even at rest?

Rapid breathing at rest can be a sign of stress, pain, exercise intolerance, or respiratory disease. If the horse's breathing remains elevated beyond normal levels, veterinary evaluation is recommended.

How can I recognize abdominal breathing in a horse?

Horses exhibiting abdominal breathing rely heavily on their abdominal muscles to exhale. This results in noticeable flank movement during respiration.

• In advanced cases, a heave line (a visible groove along the abdomen) may form due to chronic respiratory strain.
• If abdominal breathing is persistent, it often signals a serious underlying respiratory issue.

When does a horse develop abdominal breathing?

Abdominal breathing occurs when the horse struggles to push air out of the lungs, which is common in conditions such as:

• Equine asthma
• Recurrent airway obstruction (RAO, formerly known as heaves)
• Chronic bronchitis
• Pneumonia or lung infections
• Heat stress

Why is my horse breathing loudly?

Loud breathing sounds may indicate narrowed or inflamed airways. Common causes include:

• Laryngeal hemiplegia (roaring)
• Hay dust allergies (RAO)
• Respiratory infections
• Excessive mucus buildup

If the noisy breathing worsens during exercise, veterinary assessment is advised.

Why is my horse "pumping" while at rest?

If a horse appears to be "pumping" its flanks excessively while at rest, it could be experiencing oxygen deficiency, pain, or respiratory distress.

Immediate veterinary attention is required if the horse also displays:

• Flaring nostrils
• Bluish or pale mucous membranes
• Labored breathing with visible effort

When should I be concerned about my horse’s breathing?

A healthy horse breathes 8 to 16 times per minute at rest. Warning signs include:

• Breathing rate consistently above 20 breaths per minute
• Excessive nostril flaring
• Abdominal breathing
• Persistent coughing or nasal discharge
• Bluish or pale gums and mucous membranes

If any of these symptoms appear, seek veterinary advice immediately.

How can I help my horse with respiratory problems?

• Maintain a dust-free environment with proper stable ventilation.
• Feed steamed or soaked hay to minimize inhalation of dust and mold spores.
• Provide regular turnout and fresh air to support lung function.
• Use inhalation therapy with saline solutions to soothe the airways.
• Schedule regular veterinary check-ups to monitor respiratory health.

Can stress affect a horse’s breathing?

Yes, stress can cause rapid or shallow breathing. Factors such as:

• Separation anxiety
• Transport stress
• Changes in environment
• Incorrect training methods

can increase respiratory rate. Horses that are consistently anxious may also develop elevated breathing even at rest.

Why does my horse struggle to breathe when ridden?

If a horse has significantly labored breathing under exertion, this may indicate:

• Reduced lung capacity
• Laryngeal hemiplegia (roaring)
• Equine asthma or RAO
• Chronic bronchitis

A higher respiratory resistance or limited oxygen intake causes rapid fatigue and reduced stamina. Veterinary evaluation is necessary to determine the cause.

Can I train my horse to improve breathing efficiency?

Yes, targeted training can enhance lung capacity and respiratory efficiency. Beneficial exercises include:

• Interval training with gradual intensity increases
• Regular outdoor exercise in fresh air
• Hill work to strengthen the respiratory muscles

For horses with chronic respiratory conditions, any training program should be approved by a veterinarian.

What can I give my horse for breathing problems?

For respiratory support, horses can benefit from:

• Steamed or soaked hay to minimize dust exposure
• Omega-3 fatty acids (from flaxseed or hemp oil) to reduce inflammation
• Herbs such as marshmallow root, licorice root, thyme, and eucalyptus, which have expectorant and soothing properties
• Saline inhalation therapy to loosen mucus and clear airways
• Bronchodilators (only under veterinary supervision) to help open the airways in severe cases
• Corticosteroids or antihistamines (prescribed by a vet) for allergic respiratory conditions

Proper stable management, ventilation, and minimizing dust exposure are also key to maintaining respiratory health.

What are the similarities between the horse and human circulatory systems?

Horses and humans share several fundamental similarities in their circulatory systems:

• Both have a four-chambered heart (two atria and two ventricles) that pumps oxygenated blood throughout the body.
• Arteries, veins, and capillaries facilitate the transport of oxygen and nutrients.
• Both systems rely on hemoglobin in red blood cells to carry oxygen.
• Heart rate increases with exercise to supply muscles with more oxygen.
• Both species have an autonomic nervous system regulating heart function (sympathetic and parasympathetic control).

The main difference is scale and efficiency—a horse's heart is much larger, and its circulatory system is adapted for high-speed endurance and rapid oxygen transport.

What medication is used for horse breathing problems?

Depending on the condition, a veterinarian may prescribe:

• Bronchodilators (e.g., Clenbuterol) to relax the airway muscles and improve airflow
• Corticosteroids (e.g., Dexamethasone or Prednisolone) to reduce inflammation in cases of equine asthma or RAO
• Antihistamines for allergy-related respiratory issues
• Mucolytics (e.g., Acetylcysteine) to help break down mucus in the airways
• Antibiotics (e.g., Trimethoprim-Sulfa) if a bacterial infection is present
• Nebulized saline or medication therapy for direct airway treatment

All medications should be used only under veterinary guidance, as improper use can have side effects or lead to medication resistance.

What is a normal digital pulse for a horse?

A normal digital pulse in a healthy horse should be faint or difficult to detect. A strong or bounding pulse may indicate laminitis, inflammation, or circulatory issues in the hoof.

• Normal: Barely detectable
• Abnormal: Strong, throbbing, or bounding pulse (sign of pain, inflammation, or compromised circulation)

Digital pulses should be checked regularly, especially in horses prone to laminitis or foot pain.

What is a healthy heart rate for a horse?

A horse’s normal resting heart rate varies depending on age, fitness, and stress levels.

• Adult horse (resting): 28–44 beats per minute
• Foal (newborn): 80–100 beats per minute
• Yearling: 40–60 beats per minute
• During exercise: Can increase to 180–240 beats per minute, depending on intensity

An elevated heart rate at rest may indicate pain, stress, fever, or illness and should be evaluated by a veterinarian if persistent.

What tool would you use to monitor the heart rate of a horse?

The most common tools for monitoring a horse’s heart rate include:

• Stethoscope: Used to listen to the heart behind the left elbow (most accurate for resting heart rate).
• Heart rate monitor: Wireless sensors attached to a girth or electrode pads measure heart rate during exercise.
• Digital pulse oximeter: Measures pulse and oxygen levels, though not always practical for horses.
• ECG (electrocardiogram): Used for more detailed cardiac assessments, typically in a veterinary setting.

For regular monitoring, a stethoscope or heart rate monitor is the most practical tool for owners and trainers.