Heart Rate and Heart Rate Variability in Athletic Horses Vary by Age and Activity Level

Horses that participate in equestrian sports typically retire around the age of 15. However, exceptionally skilled horses may continue their careers beyond this age, raising concerns about their welfare. This study investigated animal welfare by observing resting heart rate (HR) and heart rate variability (HRV) metrics in geriatric horses participating in similar training or physical activities, compared to adult horses over 30-minute periods. Forty-six horses of varying ages and activities were divided into four groups: horses under 15 years practising structured training for dressage (AL-1; N = 13) and school riding (AL-2; N = 13), and horses aged between 15 and 20 years participating in AL-1 (N = 10) and AL-2 (N = 10). In young horses, HR decreased in those performing AL-1, observed alongside an increased RR interval compared to those participating in AL-2. Meanwhile, HRV increased in young horses but decreased in geriatric horses participating in AL-1 when compared to their counterparts in AL-2. Young horses demonstrated more positive autonomic responses while receiving structured exercise for equestrian dressage than geriatric horses. These findings highlight the need for careful management of physical activities to ensure the well-being of all horses, particularly older ones.