Heart Rate and Heart Rate Variability of Amateur Show Jumping Horses Competing on Different Levels.

Heart rate is one of the gold standards used to assess the workload level and fitness of horses. However, when slight differences need to be detected, it is not sensitive enough. Therefore, the aim of this study was to test the effect of competition level and phase of exercise on the heart rate and heart rate variability parameters in show jumpers. Fourteen horses were examined competing on three different levels: 100 cm (n = 4), 120 cm (n = 6), and 130 cm (n = 4). The length of work (min); average and maximum heart rate; average, maximum and minimum RR intervals (ms); SD1 and SD2 (ms); RMSSD (ms) and pNN50 (%); VLF, LF, HF (%) were analyzed. The measurement was divided into four phases: warm-up, resting period, show jumping course riding, and cool-down. The level of the course had no significant effect on average and maximum heart rates throughout the entire exercise. The maximum RR interval, RMSSD, pNN50, SD1, and %VLF values were significantly different (p < 0.05) in horses competing at 100 cm height from those competing in the 120 cm group. The SD1 value was sensitive for the level of competition, while the SD2 parameter was sensitive for detecting exercise phases. In conclusion, heart rate variability parameters are more sensitive for detecting smaller differences in workload than heart rate alone in lower-level show jumpers.