Abstract
Background:
Emotional contagion in human-horse interactions has been widely studied, yet the role of body language in stress transfer remains insufficiently explored.

Aim:
This study examines whether human emotional states, particularly stress and anxiety, influence horses and whether the transmission occurs primarily through body language.

Methods:
A repeated-measures within-subjects design was used. The order of interaction styles was randomized across subjects during 33 horse-human interactions. Participants were categorized as High-Anxiety (HA) or Low-Anxiety (LA) based on State Anxiety Scale scores and HR measurements. HA was defined as a score above 40 and HR > 20 bpm above resting; LA was defined as a score below 40 and HR within 2 bpm of resting values. Two interaction conditions were tested: Free-Style (FS), where participants moved naturally, and Constrained-Style (CS), where movement and expression were restricted. Horses heart rate variability and ethogram scores were recorded at baseline, during contact, and after recovery. To evaluate the influence of handler anxiety level and approach style on physiological and behavioral responses in horses, a series of two-way analyses of variance (ANOVA) were performed.

Results:
Results indicated that horses exhibited significantly higher response in HRV and ethogram scores for HA-FS interactions compared to HA-CS (p < 0.05), suggesting an increased physiological and behavioral response when human emotions were freely expressed. However, interactions in the CS condition showed no significant HRV or behavioral differences between HA and LA groups, implying that constrained body language mitigates emotional contagion.

Conclusion:
These findings suggest that horses do not inherently detect human stress but rather respond to body language cues associated with anxiety. The study highlights the importance of structured handling techniques to minimize stress transfer, with implications for equestrian training and equine-assisted interventions. By adopting controlled, neutral body language, handlers can create a more stable environment, enhancing horse welfare and optimizing human-horse interactions. This research contributes to the broader understanding of interspecies emotional dynamics and the necessity of mindful equine management practices.

Key words: Horse-human interactions; Interspecific emotional contagion; Body language; Equine heart rate variability (HRV).