A Relaxed Horse-A Relaxed Client? An Experimental Investigation of the Effects of Therapy Horses' Stress on Clients' Stress, Mood, and Anxiety.
Authors: Müller-Klein Alicia, Braun Moritz Nicolai, Ferreira de Sá Diana S, Michael Tanja, Link-Dorner Ulrike, Lass-Hennemann Johanna
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary In equine-assisted therapy, the horse's mental state is increasingly recognised as crucial to client welfare, yet research has remained one-sided: whilst evidence shows horses detect and respond to human stress, whether clients reciprocally perceive equine stress has never been systematically examined. Müller-Klein and colleagues addressed this gap through a within-subjects design where horse-naïve participants interacted with the same horse under two conditions—experimentally stressed and experimentally relaxed—with researchers measuring physiological stress markers (heart rate, heart rate variability, and salivary cortisol) and psychological indicators (state anxiety, positive and negative affect) in both horse and human. Despite successfully inducing measurable physiological stress responses in the horses, the participants showed no significant differences in stress biomarkers or psychological measures between interactions with stressed versus relaxed horses, suggesting humans lack intuitive sensitivity to equine physiological stress states. These findings carry substantial implications for equine professionals: if clients cannot consciously register a horse's stress level, handlers cannot rely on non-verbal feedback to adjust their approach, potentially compromising both therapeutic efficacy and animal welfare—making explicit education on equine stress signals and systematic welfare monitoring essential safeguards in equine-assisted work.
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Practical Takeaways
- •Horses' stress states may not be consciously detected by handlers or therapy clients, even when physiologically evident—establish objective monitoring protocols rather than relying on intuitive perception
- •The inability of humans to read equine stress levels highlights the importance of formal training in equine behaviour and stress recognition for anyone working in equine-assisted therapies
- •Safety protocols in equine-assisted services should assume that handlers cannot reliably gauge horse welfare through observation alone; implement structured pre-session stress assessments independent of human judgment
Key Findings
- •Experimental stress and relaxation manipulations in horses were physiologically successful, confirmed by horses' heart rate, heart rate variability, and salivary cortisol indicators
- •Participants showed no significant differences in physiological stress markers (heart rate, heart rate variability, salivary cortisol) or psychological indicators (state anxiety, affect) when interacting with stressed versus relaxed horses
- •Humans cannot intuitively recognize physiological stress levels in horses during standardized interactions
- •Lack of human perception of equine stress has implications for safety, communication quality, and bonding effectiveness in equine-assisted services