DO HORSES HOLD THEIR BREATH WHEN JUMPING FENCES?
I ran a poll on this and most people said NO – 54%! A knowledge of physiology, biomechanics and the scientific literature would suggest they SHOULD hold their breath when jumping a fence but in reality, we really don’t know. Below is a figure I produced some years ago to explain what I think happens, but I really don’t know.
So let’s review the evidence that might help us answer this question!
INTUITION: When riding we just have a feeling they hold their breath over a jump and breathe out on landing.
SOUND: When a horse jumps we hear what we assume to be a big intake of air on take-off and a big rush out on landing.
RESPIRATORY-LOCOMOTORY COUPLING: Horses take one breath in synchrony with each stride at canter and gallop. So if jumping from canter and the horse is not “cantering” over the fence then this would suggest they transiently halt their breathing.
NOSTRIL APPEARANCE: Horses have the ability to dilate their nostrils and this does vary slightly throughout the stride but this may not directly correlate with airflow.
OVERGROUND SCOPING: Viewing videos of horses jumping whilst being scoped suggests some changes to the larynx in many horses, but this cannot be used to infer whether they hold their breath unless the larynx is closed the whole time. And remember, horses that are being scoped are likely to have a suspected upper airway abnormality, so what we say may not apply to all horses.
GIRTH TENSION – Girth tension does change over a jump, but girth tension at canter and gallop is entirely due to limb movement and not breathing as horses lock their chest during canter and gallop and all ventilation (movement of air in and out of the lungs).
AIRFLOW – THE GOLD STANDARD FOR BREATHING!
The only definitive way to know for sure if or how a horse breathes over a jump would be to measure airflow continuously which would require a mask system (see photo below), but perhaps surprisingly, in all these years of equine exercise physiology research no one has done this, to the best of my knowledge, and if they have, they haven’t published it.
WHAT DO HORSE OWNERS THINK?
I ran a poll of horse owners and the results were interesting with less than 1/3rd thinking they held their breath when jumping.
It would seem likely they inhale on take-off, hold their breath over the jump and exhale on landing, and possibly don’t breathe at all through SJ combinations!
If you are interested in this topic, here is a copy of an article I wrote on “Breathing, Stride, and Jumping Performance”: Click here