Anticipatory response before competition in Standardbred racehorses.
Authors: Bohák Zsófia, Harnos Andrea, Joó Kinga, Szenci Ottó, Kovács Levente
Journal: PloS one
Summary
# Editorial Summary: Anticipatory Stress Response in Standardbred Racehorses Standardbred stallions exhibit measurable physiological anticipation before competition that extends beyond the immediate exercise period. Researchers compared eight horses undergoing mild training exercise with their performance during actual harness races, measuring heart rate variability (HRV) parameters and plasma cortisol at multiple timepoints including baseline, post-warm-up, post-exercise, and 30-minute recovery phases. Baseline cortisol concentrations nearly doubled before racing compared to training sessions (171.8 versus 97.3 nmol/L), and remained significantly elevated throughout all race-related samples; the sympathetic/parasympathetic balance (LF/HF ratio) also shifted substantially pre-race (12.0 versus 5.9), indicating heightened sympathetic dominance in anticipation of competition. Whilst these findings confirm that horses mount a genuine anticipatory stress response rather than responding solely to physical demands, the incomplete alignment between HRV indicators and cortisol elevation suggests that different autonomic parameters capture different aspects of pre-competitive psychology. For practitioners managing competition horses, baseline cortisol sampling or HRV assessment during routine training may help identify individual stress responders and inform conditioning protocols, though reliance on HRV alone could underestimate the psychological load horses experience before racing.
Read the full abstract on PubMed
Practical Takeaways
- •Standardbred racehorses show measurable physiological stress responses (elevated cortisol and sympathetic nervous system activation) in anticipation of racing, before any physical effort begins—account for this when conditioning horses for competition
- •Pre-race stress hormone elevation persists throughout racing effort, suggesting mental/competitive stress compounds physical exertion stress—consider stress management strategies in training
- •Heart rate variability may not be a reliable standalone indicator of anticipatory stress in racehorses; cortisol assessment provides more definitive stress measurement if needed for individual horses
Key Findings
- •Baseline LF/HF ratio was significantly elevated before racing compared to training (12.0 vs 5.9, P=0.009), indicating sympathetic nervous system activation in anticipation of competition
- •Pre-race cortisol levels were nearly double pre-training levels (171.8 vs 97.3 nmol/L, P<0.001), demonstrating clear anticipatory stress response before race
- •Cortisol remained elevated throughout all race stages compared to training (P=0.012), with no significant variation between individual race stages
- •Heart rate variability RMSSD did not differentiate between pre-race and pre-training conditions, suggesting HRV parameters only partially reflect anticipatory stress in this context