Abstract
BACKGROUND: Emotional contagion in human-horse interactions has been widely studied; however, 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 HCIs. Participants were categorized as high-anxiety (HA) or low-anxiety (LA) based on State Anxiety Scale scores and heart rate (HR) measurements. HA was defined as a score >40 and HR > 20 bim above resting; LA was defined as a score of 40 and HR 2 bim of resting values. Two interaction conditions were tested: free-style, where participants moved naturally, and constrained-style (CS), where movement and expression were restricted. 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 variances was performed. RESULTS: Horses exhibited significantly higher HRV and ethogram scores for High-Anxiety Free Style interactions than High-Anxiety Constrained Style (p < 0.05), showing 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 the HA and LA groups, implying that CSBL mitigates emotional contagion. CONCLUSION: Horses do not inherently detect human stress but rather respond to body language cues associated with anxiety. This 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 need for mindful equine management practices.