https://phaidra.vetmeduni.ac.at/o:4082 Heart rate and salivary cortisol as indicators of arousal and synchrony in clients, therapy horses and therapist in equine-assisted therapy Naber, Anna Anna Naber Kreuzer, L. L. Kreuzer University of Veterinary Medicine Vienna Zink, Roswitha Roswitha Zink Millesi, Eva Eva Millesi Palme, Rupert Rupert Palme 0000-0001-9466-3662 University of Veterinary Medicine Vienna Hediger, Karin Karin Hediger Glenk, Lisa Lisa Glenk 0000-0002-5814-0546 University of Veterinary Medicine Vienna Elsevier journal article open access eng This exploratory study aimed to analyse physiological interaction processes in equine-assisted-therapy (EAT) between client, therapy horse and therapist.We measured heart rate (HR), heart rate variability (HRV) and cortisol levels before, during and after a standardized therapy session and a control condition in one therapist, four therapy horses and ten female clients in emerging adulthood (Mn = 21.8 years, SD = 3.39). The clients were diagnosed with mild (N = 5) to moderate (N = 5) intellectual disability (ID).There was no significant change in the client's HR, HRV and cortisol levels during an EAT session. No difference was observed between therapy sessions with or without a therapy horse, except during the challenge phase of the EAT protocol, where clients had a significantly lower HR when interacting with the therapy horse. HR between therapist and client correlated significantly, as well as between therapist and horse. This effect was greater when therapists interacted with a familiar horse. Clients' and horses' HRs also correlated, but only when the horse was the clients' familiar and preferred horse.These results indicate that relationship intensity is an important factor for the synchronization process. Moreover, the inclusion of horses in a therapeutic setting can lead to a decreased HR in young adults with intellectual disability while mastering a challenge. Future research should investigate this potential benefit of EAT, considering the reciprocal influences and the relationship between client, therapist and horse. Female Hydrocortisone Analysis Hydrocortisone Metabolism Equine-Assisted Therapy Methods Humans Animals Heart Rate Physiology Horses Saliva Chemistry Young Adult Adult Arousal Physiology Intellectual Disability Therapy Male http://creativecommons.org/licenses/by-nc-nd/4.0/ https://phaidra.vetmeduni.ac.at/api/object/o:4082/download 10.1016/j.ctcp.2025.101937 https://phaidra.vetmeduni.ac.at/o:605 application/pdf Complementary Therapies in Clinical Practice issn:1873-6947 VoR Complementary Therapies in Clinical Practice 59 2.59 MB 2025