Heart rate and salivary cortisol as indicators of arousal and synchrony in clients, therapy horses and therapist in equine-assisted therapy.

Research Overview

• This study explored physiological interactions—specifically heart rate, heart rate variability, and cortisol levels—among clients with intellectual disabilities, therapy horses, and therapists during equine-assisted therapy.
• The research focused on measuring these indicators before, during, and after therapy sessions to understand arousal and synchrony within the triad (client, horse, therapist).

Purpose and Background

• Equine-assisted therapy (EAT) involves using horses as part of therapeutic interventions to support physical, emotional, or psychological health.
• The study aimed to analyze interaction and synchronization through physiological signals to better understand how clients, horses, and therapists connect during therapy.
• Measuring heart rate (HR), heart rate variability (HRV), and cortisol (a stress hormone) serves as indicators of arousal and synchrony between participants in the therapy.

Participants and Methods

• Participants included:
  • 10 female young adults with mild to moderate intellectual disability (average age ~21.8 years).
  • 1 therapist conducting the sessions.
  • 4 therapy horses involved in the sessions.
• Two conditions were compared:
  • EAT session with a therapy horse present.
  • Control therapy session without a horse.
• Physiological measures included:
  • Heart rate (HR) – number of heart beats per minute.
  • Heart rate variability (HRV) – variation in time intervals between heartbeats, signaling autonomic nervous system activation and emotional regulation.
  • Cortisol levels in saliva – physiological marker of stress response.
• Measurements were taken at three times:
  • Before the therapy session.
  • During the therapy session.
  • After the therapy session.

Key Findings

• No significant changes were found in client’s HR, HRV, or cortisol levels when comparing the therapy session with or without a horse overall.
• During the “challenge phase” of EAT (a specific part of the therapy designed to test or engage clients), clients showed significantly lower heart rates when working with the therapy horse, indicating reduced physiological arousal or stress.
• Heart rate correlations were observed between:
  • Therapist and client, showing physiological synchrony.
  • Therapist and horse, with stronger synchrony when the horse was familiar to the therapist.
  • Client and horse, but only when the horse was both familiar and preferred by the client.

Interpretation and Implications

• Synchronization in heart rate suggests emotional or physiological connection between participants in therapy sessions.
• The fact that relationship intensity (familiarity and preference) strengthens synchrony underscores the importance of established bonds for positive interaction outcomes.
• The reduction in heart rate during challenging tasks with a therapy horse suggests that horses may help clients with intellectual disabilities manage stress or anxiety when facing difficulties.
• Overall, these findings imply that horses can play a calming and synchronizing role in therapy, particularly when the client is connected with a familiar horse.
• The results support the therapeutic potential of including horses in clinical settings, highlighting the need to consider the relational dynamics among client, therapist, and horse.

Future Research Directions

• Further investigation is required into the reciprocal influences between client, therapist, and horse during therapy.
• Studies involving larger, more diverse samples could validate and expand upon these findings.
• Research should explore the mechanisms by which familiarity and preference affect physiological synchrony and therapeutic outcomes.
• Exploring how EAT influences behavioral, emotional, and cognitive functioning alongside physiological measures would provide a more comprehensive picture of therapy benefits.