The basics of the heart rate in the racehorse

The heart rate is the number of contractions initiated by the heart over a given period of time. It is usually measured in beats per minute (or BPM), and is essential in assessing the fitness of a racehorse.

At rest, a horse’s heart rate range from 25 to 40 BPM on average. However, it can vary up to more than 100 BPM under the influence of excitement, fear, or any other event. For example, the mere presence of a person in the stall or around a horse can also increase the resting heart rate. A low resting heart rate indicates good physical condition and relaxation, while a high resting heart rate is usually associated with overtraining, illness or poor physical condition.

During a physical effort or training, the horse’s heart rate increases significantly. Indeed, the heart rate evolves linearly with the effort intensity. In general, the maximum heart rate of a horse, i.e. the heart rate that a horse cannot exceed, is around 218 BPM.

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Keys to analyzing a racehorse’s heart rate

 

1. Analyze the maximum heart rate to evaluate the intensity of the effort

The maximum heart rate of a horse (or max HR) measures the maximum number of beats per minute that a horse can reach during its effort. When a horse reaches its maximum heart rate, it gallops at a speed that it can only sustain for 600 to 800 meters. This max HR varies depending on the horse and its predispositions. On average, it is between 204 and 241 BPM (Evans, 2007).

Evaluating a horse’s heart rate allows to personalize its training and to make him work at percentages of his max HR adapted to its capacities. For example, training at 70% of a horse’s heart rate would be an active recovery, which can be effective in improving blood flow and aerobic fitness as well as stamina.

It is important to know that the maximum heart rate does not vary according to the volume or quality of a horse’s training. In the long term, it decreases slightly with age. However, the speed reached at maximum heart rate can vary according to the training. If it increases, it is a good sign and indicates a good state of fitness: the horse is able to gallop faster for the same heart rate.

It is important to remember that the max HR is closely linked to the efficiency of the heart. A strong heart does not need to beat as fast to expel the same amount of oxygen as a weaker heart. A blood system that is better supplied with oxygen by the heart has a higher resistance to effort.

2. Four heart rate zones to analyze to evaluate the physical condition of a race horse

The heart rate depends on the activity of the horse. Thus, the heart rate of a horse during a work is totally different from that at rest. It can therefore be analyzed by dividing the exercise into different intensity zones:

1/ The working zone: heart rate and speed are high. The horse is actively working and improving its aerobic and anaerobic qualities.

2/ The deceleration zone at the end of the work: the speed decreases drastically, but the heart rate remains high. This zone marks the end of the intense training and the beginning of the “return to calm”, it is fundamental in improving the horse’s performance.

3/ The zone of rapid decrease of the heart rate: the speed remains low, and the heart rate slows down strongly.  It can last more or less time depending on the horse. The shorter the rapid decay zone, the greater the horse’s ability to recover quickly.

4/ The slow heart rate decay zone: the speed is minimal (walk or slow trot) and the heart rate decrease gradually slows down. This is the slow recovery zone, at which point the effort is usually over since about 15 minutes. The fittest horses will have fallen back to a low heart rate, close to their average resting heart rate.

EQUIMETRE platform view, Analytics view
During both trainings circled in red, Arion had an abnormally high heart rate as he engaged in his first trot. This value puts to light overtraining, an injury or any undesirable pathology.

3. Heart rate during warm-up

By gathering all the heart rate data of your horses, Equimetre Analytics Premium (EAP) allows to distinguish an average data range for each horse. Hence, it is possible to detect any abnormal value and to identify unwanted variations before, during or after training. This enhances prevention work and minimizes drastically the risk of injury. The main parameters to be monitored are: heart rate during the first gallop and trot (an abnormal increase is generally due to pain), recovery, speed and locomotion data (regularity, stride length, symmetry).

4. Speed at 200 beats per minute, or V200

V200 measures the speed a horse reaches when its heart is beating at a rate of 200 beats per minute. V200 is a useful parameter for comparing horses in a stable. A horse with a higher speed than another horse with the same heart rate is considered more physically fit. This characteristic can be worked on in training and can be compared over time in the same horse. Indeed, if a horse increases its V200, it is a sign of effective training.

5. The ECG as a tool to investigate pathologies

The ECG is a graphic model of the electrical activity of a horse’s heart. The heart beats to the rhythm of electrical signals that the electrocardiogram (or ECG) collects. Up to this day, ECG analysis is one of the few ways for veterinarians to detect cardiac arrhythmias (such as atrial fibrillation).

Example of atrial fibrillation

Moreover, some arrhythmias are only revealed during exercise, hence the need to work with a tool that can monitor the horse regardless of its gait. EQUIMETRE’s precise and continuous ECG analysis allows to signal any worrying deviation.

 

 

 

 Why measure heart rate in racehorses?

 

Heart rate analysis has many virtues in the life of a racehorse. In an increasingly competitive sector, its analysis is an undeniable competitive advantage. Moreover, the frequent analysis of your horse’s ECG is a precious asset for his health and well-being.

From a performance point of view, the collection of cardiac data improves the quality of the follow-up of your race horses. For example, you can measure the evolution of a horse by comparing its V200 at several moments of the season and its career. Tracking heart rate also allows you to evaluate the fitness of a horse, thanks to the evaluation of his recovery. Finally, by analyzing the percentage of max HR at which your horses worked, you can deduce the intensity of the exercise performed.

Regarding your horses’ health, the ECG plays an equally important role. It allows you to prevent and detect possible pathologies or pain. A heart rate higher than usual usually highlights unwanted stress or pain suffered by your horse. It can also indicate overtraining, which can have a negative impact on his performance and career.

You now have all the keys in hand to analyze the heart rate collected, during exercise or at rest, by EQUIMETRE!