Horse Side Vet Guide ®

Equine Health Resource

Respiratory Noise when Exercising

Code Red - Call Your Vet Immediately, Even Outside Business Hours

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

Code Red - Call Your Vet Immediately, Even Outside Business Hours

  • If the results of the Whole Horse Exam (WHE) indicate fever (Temp>101F/38.3C), or heart rate greater than 48 BPM that persists an hour after recovery from exercise.
  • If you feel the problem is severe or has come on suddenly.
  • If you think the horse is having difficulty breathing.
  • You can also hear obvious respiratory noise when the horse is at rest.

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

  • If you consider this a chronic and relatively mild problem that is not changing rapidly.
  • If your horse seems to be performing well otherwise.

The windpipe (trachea), voicebox (larynx), pharynx, and nasal passages make up the upper airway. Respiratory noise happens when there is a change in the anatomy or function of any part of the upper airway, and which interferes with normal smooth airflow. Turbulent airflow causes noise.

Diseases of the lower respiratory tract (lungs) are less likely to cause obvious sounds.

Some respiratory noise is normal. A common puffing, blowing sound is heard at each stride of the canter in some horses. This is known in the horse world as “High Blowing” and usually refers to vibration of the nostril or false nostril during exhalation. It is generally not considered a problem.

But there are a variety of conditions affecting the upper airway of performance horses that cause respiratory noise that only exist or become apparent during exercise. The negative pressures during inspiration cause collapse of various structures of the upper airway into the path of the air resulting in audible, turbulent sounds.

The most familiar abnormal condition causing audible respiratory noise is laryngeal hemiplegia, or left laryngeal paralysis. This causes a sound known in the horse world as “roaring”. But there are many other less common conditions.

Not all conditions causing respiratory noise negatively affect performance. It can be hard to tell whether a noise is associate with a reduction in performance. Conditions change and progress, so a problem that might be causing little trouble now (and is easily treated) could progress later into something that is both damaging to the horse and difficult to treat.


Perform the Whole Horse Exam (WHE), paying particular attention to general health- rectal temperature, heart and respiratory rates. Consider when you hear the noise. Is it only under saddle? Is it only audible at particular gaits? Does it change when there is flexion or extension of the poll? Can you hear it at all when the horse is resting? Do you notice whether the sound occurs on the out-breath (exhalation) or in-breath (inhalation)? Discuss your observations and your concerns with your vet.


Using physical examination at rest and observation under saddle, and usually using standing and/or dynamic endoscopy, your vet can identify the condition causing the respiratory noise and provide you with treatment options.

Author: Doug Thal DVM Dipl. ABVP


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