Association of heart rate variability, exercise intensity and exercising arrhythmias with competition results in eventing horses.
Authors: Navas de Solis, Ramseyer, Stefanovski, Haughan, Solomon, Kirsch
Journal: Equine veterinary journal
Summary
# Editorial Summary: Heart Rate Variability and Arrhythmias in Eventing Competition Exercising arrhythmias are well-documented in event horses, yet their relationship to performance and fatigue remains poorly understood; this study examined whether heart rate variability metrics and arrhythmia occurrence during 2–4* cross-country competitions could predict competition outcomes in 43 horses across two European nations. The researchers analysed 69 competition electrocardiograms alongside blood lactate concentrations, peak and mean heart rates, and finish results using multivariable regression modelling, with particular focus on Detrended Fluctuation Analysis alpha1 (DFA-α1)—a measure of heart rate fluctuation patterns proposed as an exercise intensity marker. Counterintuitively, more premature complexes, complex arrhythmias, and arrhythmias during recovery were associated with fewer time penalties in the cross-country phase, whilst higher blood lactate, peak heart rate and mean heart rate also correlated with faster times; however, complex arrhythmias and recovery-phase arrhythmias predicted increased penalties in the showjumping phase, and higher DFA-α1 values during cross-country associated with fewer showjumping faults. For practitioners, these findings suggest that some arrhythmia patterns may reflect higher cardiovascular stress tolerance or aggressive pacing rather than pathology, yet the small effect sizes, wide confidence intervals, and inconsistency between phases mean caution is warranted—the critical question of which specific arrhythmias warrant clinical concern for safety and performance remains unanswered.
Read the full abstract on PubMed
Practical Takeaways
- •Exercising arrhythmias during cross-country are very common and the presence of certain arrhythmia types does not necessarily indicate poor performance; however, their specific clinical significance remains unclear
- •Arrhythmias observed during cross-country may predict reduced jumping performance in the subsequent phase, suggesting fatigue or cardiac effects may carry over between phases
- •Current evidence is insufficient to determine which arrhythmia types warrant concern for safety or performance; practitioners should not use arrhythmia presence alone to assess competition fitness
Key Findings
- •Arrhythmias were frequent in 69 cross-country competition ECGs from 43 horses, occurring in most recordings
- •Higher DFA-α1 during cross-country was associated with fewer showjumping penalties, but DFA-α1 was not associated with cross-country performance
- •More premature complexes, complex arrhythmias, and arrhythmias during recovery were associated with fewer time penalties during cross-country phase
- •Complex arrhythmias and recovery-phase arrhythmias during cross-country were associated with more penalties in the subsequent showjumping phase
- •Higher blood lactate, peak heart rate, and mean heart rate were associated with fewer time penalties during cross-country