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Horse Heart: A Guide to Rate (BPM), Size, and Function

Last updated: February 24, 2023

By: Miles HenryFact Checked

As a horse owner, I’ve always been fascinated by their anatomy, and one of the most intriguing organs is their heart. It has incredible pumping power that makes it possible for horses to run fast and cover long distances efficiently.

A horse’s heart is a melon-sized organ weighing 8 – 9 pounds. It beats 28 – 46 times per minute but can rise to 260 beats per minute when running. Horses with larger, stronger hearts often function better at physical tasks.

Did you know an exercising horse’s heart can pump up to 250 liters of blood per minute from its heart? A horse’s heart rate is quite sensitive to stimuli. Therefore, it’s essential to know how to measure the heart rate and what is considered abnormal.

Horse heart rate: what is normal? What is too high?

When I was a kid, I was often worried about how high our horse’s heartbeats while trotting. I later learned that, for horses, a regular heart rate spans a pretty broad range.

An adult horse’s normal resting heart rate ranges from 28 to 46 beats per minute (BPM). Smaller breeds tend to have higher heart rates than larger ones.

Picture of a horse with a heart

Foals have a heart rate of 70 – 120 bpm. The heart rate gradually decreases as a horse grows up. When the foal is a few months old, its heart rate is about 60 – 80 bpm.

A horse’s resting heart rate is the number of times its heart beats at rest; this is typically 15 – 30 minutes after any activity and when it isn’t excited or stressed out from a vet visit.  

A resting heart rate greater than 50 – 60 bpm for an extended period is generally considered high. Sick horses may have heart rates as high as 120 bpm.

Besides excitement and stress, an increased resting heart rate may indicate metabolic or respiratory problems, infection, pain, and cardiovascular problems.

In general, the heart rate is a reliable way to determine a horse’s fitness. So, if the resting heart rate of your horse is high for an extended amount of time, a call to the vet is necessary.

Picture of an equine heart monitor
Polar horse heart rate monitor

What should your horse’s heart rate be during exercise?

A horse’s heart rate can vary widely depending on what the horse is doing. The smooth transition from a low to an extreme heart rate proves the horse’s athletic prowess.

A horse’s heart rate during heavy exercise, like galloping, is around 220 – 260 bpm. The maximum heart rate value depends on the individual horse and decreases as the horse gets older.

Taking a horse for a walk can increase its heart rate to more than 70 bpm. Trotting may induce a heart rate of 70 – 125 bpm. The canter (which is usually faster than a trot) can cause 120 – 170 bpm.

For example, endurance horses in good condition often arrive at checkpoints with heart rates of 125 – 200 bpm.

A horse’s heart rate during exercise also depends on the weight of the rider, track condition, and whether or not the horse is excited or stressed out. I’m old school and don’t always jump to the latest technology, but after reading about the benefits of training young horses with a heart rate monitor, I bought one.

I chose the Polar Equine heart rate monitor because Polar has a good reputation for making reliable heart monitors; it’s simple to use and works with blue tooth, so you can link it to your phone or watch.

How long does a horse’s heart rate take to recover back to normal?

It can take about 15 – 60 minutes for your horse’s heart rate to recover back to normal after exercise. The recovery time also depends on the heart rate it reaches during training and what it does after the workout.

As a horse ends its exercise, the heart rate falls rapidly for the first one or two minutes and then declines more slowly.

For instance, the heart rate of a horse that’s slowed down from a gallop to a walk and then comes to rest may fall from 220 to below 100 bpm in 2 – 3 minutes and take up to an hour to go below 40 bpm.

Is it okay if a horse’s heart has an irregular rhythm?

Sometimes, you may have noticed that your horse’s heart isn’t beating at regular intervals. It certainly had me calling a vet on more than one occasion.

Slight variations in the heartbeat (or irregular rhythm) may seem dangerous, but it’s not something to be concerned about most of the time.

A horse’s heart is incredibly sensitive to external stimuli. So, it’s natural for the heart rate to vary from beat to beat as the horse responds to random noises, suddenly getting patted on the back, or even breathing a sigh.

However, an irregular heart rhythm can also indicate serious health issues, so you should be able to recognize an abnormal heart rhythm and know when to consult a vet.

Horses have a wide range of heart rate values and a sensitive nervous system. Therefore, they are well-adapted to quickly shifting their heart rates based on the physiological condition of the horse.

Variations in heart rhythm show that a horse is reacting healthily to its environment. In fact, a prolonged, steady heart rhythm is not normal.

In contrast, an extreme example of a heart rhythm abnormality (arrhythmia) is atrial fibrillation. It’s when the heart rhythm becomes significantly irregular or takes too long between beats.

A horse with atrial fibrillation may tire very quickly and exhibit shortness of breath. It will take longer than usual for the heart rate to recover after exercise. Some horses may also whiny or cough.

Atrial fibrillation often has no significant symptoms, and it might remain undetected if the horse only does light work. Therefore, vets use an electrocardiograph test to confirm the diagnosis of atrial fibrillation.

Your best bet at recognizing an abnormal heart rhythm is to familiarize yourself with your horse’s heart rate. If you observe any symptoms, and suspect that the pause between the beats is too long or that the heart rate is too high, it’s best to see a vet.

Vets listening to a horse heart

How do you check your horse’s heart rate?

You can check your horse’s heart rate by placing your fingers (don’t use your thumb as it has its own pulse) on any of the several arteries or by using a stethoscope.

One of these arteries is along the jawbone, under the cheek, and almost beneath the front corner of the horse’s eye. Apply slight pressure with your fingers until you feel the pulse. Count the number of beats in fifteen seconds, and multiply the number by 4 to determine the heart rate.

However, you’d need some practice to feel the pulse with your fingers. So, you can place a stethoscope behind the left elbow of the horse. Once you hear a pulse, follow the same procedure as above.

How big is a horse’s heart? How does a horse’s heart compare to a human’s?

  • An average adult horse’s heart weighs about 9 – 10 pounds and is about as big as a large melon. The biggest horse heart ever recorded weighed approximately 22 pounds.

A human heart weighs a little more than a half-pound. A horse’s heart is more than ten times heavier than a human’s.

  • A horse’s heart pumps about 35 – 40 liters of blood per minute. However, during intense galloping (when the heart rate is higher than 220 bpm), the heart may pump up to 250 liters per minute.

A human at rest pumps about 5 – 6 liters of blood per minute. And during intense exercise, we may pump 20 – 30 liters of blood per minute.

  • The heart rate of a horse has a much greater range as compared to that of a human heart. For example, a horse’s heart rate can climb from a mere 30 bpm (at rest) to more than 220 bpm (during exercise) in a few seconds.

In comparison, the resting human heart rate is 60 – 100 bpm, while the maximum heart rate during exercise is usually less than 200 bpm for adults (it decreases as you age).

Picture of our two year old running

Does heart size play a role in how well a horse performs?

Both in humans and horses, a large heart has been correlated with better athletic performance. However, can large hearts cause horses to perform better?

The size of a horse’s heart typically indicates how well it performs in competitive events. However, it’s unclear whether or not a naturally large heart significantly determines an above-average performance.

The idea that horses with big hearts are better at sports has been around for hundreds of years. Today, it’s often seen that top-performing horses have a larger-than-average heart size.

Secretariat, the horse with the highest stride angle in history and the 1973 Triple Crown winner, had the biggest recorded heart weighing 21 – 22 pounds. Unsurprisingly, his challenger Sham had a massive 18 pounds heart.

Similarly, studies on Thoroughbreds and Standardbreds have shown that trained members tend to have larger hearts than untrained ones.

However, athletic performance depends on multiple factors like speed, stride length, stride frequency, muscle mass, height, and horse training. As heart size doesn’t determine all these factors, we can’t say how much of a role it practically plays in helping your horse win the race.

One thing is positive, though; endurance and sprint training increase heart size. The size may increase up to 30%. As the heart becomes more significant, it pumps a greater quantity of blood more efficiently and contributes to better equine health.