Mythbuster Monday: Testosterone Makes the Whooshing Sound When Male Horses Run

On Mythbuster Monday, we tackle a variety of equestrian myths to either bust or confirm. Today’s discussion: Do male horses make that whooshing sound when running due to testosterone?

It’s Mythbuster Monday, where Horse Nation dives into different equestrian myths and provides research-based evidence to either bust or confirm those myths. Today’s topic: Do male horses make that whooshing sound when running due to testosterone? Do mares ever make that sound? How is the noise created? Read further to find out!

Myth: Testosterone makes the whooshing sound when geldings run

Myth or Fact: Myth


We’ve all heard the noise. A bunch of geldings are running out in the field and you hear it. You may also hear it when you’re riding, most likely at a trot or canter.

But where does it come from?

Many times it has been said that only male horses do it because the testosterone in their system allows them to create this sound. That is not the case.


In an, “Ask the Vet” video by SmartPak, veterinarian Dr. Lydia Gray discusses the noise. She states that it is due to the male horse tensing his abdominal muscles therefore allowing him to suck air in through the sheath. Pressure is then created when the male horse elongates his abdominal muscles with his stride, creating that whooshing sound.

To hear about it more in depth, the video is attached below:

According to Ida Norris, a USEF “S” judge, in an article by Dressage Today, sheath noises are created by a tensing of back muscles as air passes by the sheath. She states in some instances, it can also occur in mares in the udder area.

Norris gives examples of when this is most likely to happen. Back muscles get overly tense and the noise can be heard if the horse doesn’t have an adequate warm up, is in a new environment or is stabled in a colder atmosphere. She states this noise can be of concern if your horse produces it daily and/or for long durations.


An article by Horse Side Vet Guide states that the noise comes from a tensing of the abdominal muscles causing air to be sucked into the sheath. This article points out that it is a normal occurrence and not to be worried.

However, this sound can also be made by deep wounds in the armpits and groin. It may also be heard from the incisions after a horse is castrated. If other signs and symptoms accompany the sound then you should reach out for a veterinarian’s expertise.


Horse Listening explains the noise in their article “On Slobber, Snorts and Sheath Sounds – 3 Ways to Your Horse’s Back.” They state that many people relate a sheath sound to high testosterone or a dirty sheath area, however, this noise is due to a tight back creating a tight sheath area.

They give an exercise to lessen or even cease the sound. They recommend cantering for three to five strides and then trot. Then repeat this exercise until you notice a difference in the sound. This exercise creates impulsion in the trot, allowing the horse to stretch his back muscles.


After diving into the research, the whooshing sound created by male horses is not due to a build up of testosterone. The noise can be contributed to a stiff back and tense abdominal muscles. Some mares have exhibited this sound due to air collection in the udder area. This sound is usually not an issue unless it is accompanied by other signs and symptoms.

Do you have an equine myth you’d like us to tackle? If so, send it our way! Email your suggestions to [email protected]. Put Mythbuster Monday in your subject line.