Ohmura Hajime, Jones James H
Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan.
School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A.
J Equine Sci. 2017;28(3):99-103. doi: 10.1294/jes.28.99. Epub 2017 Sep 20.
We investigated changes in heart rate (HR) and HR variability as a function of age in newborn foals to old Thoroughbred horses. Experiments were performed on a total of 83 healthy and clinically normal Thoroughbred horses. Resting HR decreased with age from birth. The relationship between age and HR fit the equation Y=48.2X(R=0.705); the relationship between age and HR for horses 0-7 years old fit the equation Y=44.1X(R=0.882). Seven-day-old horses had the highest HR values (106 ± 10.3 beat/min). The low frequency (LF) and high frequency (HF) powers increased with age in newborn to old horses. These changes in HR and HR variability appear to result from the effects of ageing. Three- to seven-year-old race horses had the lowest HR values (32.9 ± 3.5 beat/min) and the highest LF and HF powers except for the HF powers in the oldest horses. Race training may have contributed to these changes. Horses of ages greater than 25 years old had the highest HF powers and the lowest LF/HF ratios. In individual horses, 8 of the 15 horses over 25 years old had LF/HF ratios of less than 1.0; their HR variability appears to be unique, and they may have a different autonomic balance than horses of younger age.
我们研究了从新生马驹到老龄纯种马心率（HR）及心率变异性随年龄的变化。总共对83匹健康且临床正常的纯种马进行了实验。静息心率从出生起随年龄下降。年龄与心率的关系符合方程Y = 48.2X（R = 0.705）；0至7岁马匹的年龄与心率关系符合方程Y = 44.1X（R = 0.882）。7日龄的马心率值最高（106±10.3次/分钟）。从新生马到老龄马，低频（LF）和高频（HF）功率随年龄增加。心率及心率变异性的这些变化似乎是衰老作用的结果。3至7岁的赛马心率值最低（32.9±3.5次/分钟），除最老龄马匹的高频功率外，其低频和高频功率最高。赛马训练可能促成了这些变化。25岁以上的马匹高频功率最高，低频/高频比值最低。在个体马匹中（25岁以上的15匹马中有8匹），低频/高频比值小于1.0；它们的心率变异性似乎独特，与年轻马匹相比可能具有不同的自主神经平衡。
