1. The horses’ lungs sit inside the ribcage which is the largest structure of the whole skeleton.
2. The lungs are the 3rd largest organ in the body after the skin and digestive system.
3. The lungs bring oxygen into the body and expel carbon dioxide but also have many other functions including control of body temperature, filtering clots and bubbles from the blood and whole-body acid-base balance.
4. Horses are obligate nasal breathers – they only breathe through their nostrils, not their nostrils and mouth as we do.
5. The harder a horse works the more air it must move in and out.
6. During intense exercise, a horse moves around 6 bathfulls of air in and out every minute.
7. In walk and trot breathing and gait are not linked, but in canter and gallop horses take one breath perfectly in time with each stride.
8. Horses have to hold their breath when jumping as they rely on the movement of the legs to help move air in and out of the lungs.
9. Horses “lock” their ribcage when cantering and galloping and only breathe with their diaphragm. They do not expand and contract their ribcage as we do.
10. Contrary to popular belief, fitness training does not increase respiratory capacity – at the same speed, a fit horse moves the same amount of air in and out as when unfit.
11. In unfit/untrained horses, the cardiovascular system (heart, blood vessels and blood) is the main limit to performance. In the trained horse it is the respiratory system that limits performance.
12. The most common abnormalities/diseases of the equine respiratory system are dynamic upper airway dysfunction (“roaring”, “gurgling”), asthma and exercise-induced pulmonary haemorrhage (EIPH)
13. Healthy horses don’t cough!
