A horse’s heart rate (the number of times it beats per minute) tells us how hard it’s working. The harder the horse works the higher the heart rate. It’s the equivalent of the rev counter in a car which tells us how hard the engine is having to work. If a horse is going fast on the flat then the heart rate may be up around 220bpm (near maximum for most horses) but it could also be at 220bpm for a medium speed canter up a steep hill on soft going. Heart rate is fairly easy to measure and has been important in many research studies and papers. During the research for the Atlanta Olympic Games in 1996, heart rate was essential to understand the effect of the effort and the high heat and humidity on horses, particularly during the long-format speed and endurance test which included roads and tracks, steeplechase and cross-country.
However, since Atlanta, the speed and endurance phase has changed dramatically. There is no roads and tracks or steeplechase. There are also more jumping efforts and the course is shorter. Some research has shown that the heart rates of horses are, not surprisingly, a lot higher in modern cross-country. That is the horses are having to work harder. But there have been no comprehensive studies until now.
A recent study by Katharina Kirsch and colleagues from the University of Liege and the German Olympic Committee for Equestrian Sports measured the heart rates of 294 horses competing in cross-country from 2 to 5 star level. The average heart rate (HR) at CCI2* was 196bpm, 199bpm at CCI3*, 206bpm at CCI4* and 208bpm at CCI5*. These values are considerably higher than heart rates during long-format cross-country.
What the researchers also found was that every 30 m/min increase in average speed was associated with a 3bpm increase in HR, each 30m increase in cumulative elevation was associated with an increase of 2bpm and each 20m increase in distance was associated with an increase of 1bpm. Thoroughbred horses had a 4bpm lower HR compared with Warmbloods and each 5 years increase in age was associated with a 4bpm decrease in HR. Finally, HR recovery was slower in warmer and more humid conditions.
The data from this study was used along with other research in guiding the cross-country plans for the Tokyo 2020 (now 2021) eventing cross-country test.
This paper is open access which means it can be downloaded in full for free.