“…A total of 2 studies used a portable electrocardiogram (ECG) for collecting HR data [51,59] from horses. Of studies that collected HR data, 11 reported HR alone [37,38,40,42,44,45,49,50,[54][55][56]60] and 9 reported HR and heart rate variability (HRV) measures [39,43,47,48,52,53,[57][58][59][61][62][63][64].…”