Because they feel your heartbeat! – Heart rate, heart rate variability and salivary cortisol as indicators of arousal and synchrony in equine-assisted interventions between clients with intellectual disability, therapy horses and therapists


There is a constantly growing research interest focusing on the human-horse interaction and communication based on bodylanguage.

The results show effects of human-horse interaction on improved bio-psycho-social health. The regulation of stress plays a key-role in (mental) health preservation for clients, therapists and the wellfare of therapy horses.

Social interaction also has a great impact on the cardiovascular system and therefore on the stress experience and in further consequence on (mental) health.

The process of synchronization is important for every interaction and can occur even across different species. All creatures prefer interactions with a high level of synchronization, which correlates with stress reduction.

To gain a better understanding of these processes in equine-assisted-therapy (EAT), a pilot project has been started. The aim of the study was to analyse interaction processes in focusing on physiological parameters, stress and synchronization.

Therefore, the heart rate, heart rate variability (HRV) and cortisol level have been analysed before, during and after a standardised therapy session as well as in a control condition with a barrel horse.

The results show a trend of lower cortisol and heart rate and rising HRV during human-horse interaction, emphasizing the relaxing effects of horses. Besides there have been significant correlations in heart rate between therapist and client, r = .24, p < .05 and therapist and horse, r = .53, p < .05. This effect was greater in interaction with a familiar horse, r = .70, p < .05. Clients and horses showed a significant correlation of heart rates in the interaction with a familiar horse as well, r = .38, p < .05. These results show that relationship is an important factor for synchronization, which opens up many implications for the daily routine in EAT.