The exhilaration of a gallop through a field might make your heart race, but you’re not alone: Your horse’s heart is working hard to power every stride he takes. Along with his respiratory system, a horse’s cardiovascular system serves as the engine he needs to perform everything from day-to-day activities to high-level athletic pursuits. But both systems have limits, and it’s important to understand them.

Here, Anna M. Firshman, BVSc, PhD, Dipl. ACVIM, ACVSMR, an associate clinical professor at the University of Minnesota College of Veterinary Medicine, reviews how the horse’s cardiovascular and respiratory systems function during exercise.

But first, here are a few terms and concepts you should be familiar with:

  • Heart rate (or HR) The number of times the heart beats each minute. A resting horse’s HR is generally around 30 to 40 beats per minute, or BPM, Firshman said; during exercise horses’ heart rates can increase to anywhere from 150 to more than 250 BPM, depending on the exercise intensity. Veterinarians and owners can measure HR by feeling the horse’s pulse, using a stethoscope, or via electronic means, the latter being the most practical and reliable when evaluating horses during and after exercise.

     

  • Maximal HR (HRmax) The highest rate at which a particular horse’s heart can beat. Firshman said this can range from 210 to 280 BPM.

     

  • Stroke volume (or SV) The amount of blood pumped during