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Home / Equine Research Bank / J Equine Sci / Changes in heart rate and heart rate variability as a functi...
Journal of equine science2017; 28(3); 99-103; doi: 10.1294/jes.28.99

Changes in heart rate and heart rate variability as a function of age in Thoroughbred horses.

Abstract: 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.
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Publication Date: 2017-09-20 PubMed ID: 28955161PubMed Central: PMC5608962DOI: 10.1294/jes.28.99Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigates how the heart rate and variability in heart rate of Thoroughbred horses changes as they age, from newborn foals to elderly horses.

Objective and Experimental Design

  • The objective of this study was to investigate changes in heart rate (HR) and HR variability as a function of age in Thoroughbred horses.
  • The experiments involved 83 healthy and clinically normal Thoroughbred horses of varying ages.

Findings: Heart Rate and Age

  • The study identified a clear pattern of decreasing resting heart rate with increasing age from birth. This pattern was represented mathematically by the equation Y=48.2X(R=0.705).
  • For horses between 0 to 7 years old, the relationship between age and heart rate was even stronger, with an equation of Y=44.1X(R=0.882).
  • The highest heart rate values were found in 7-day-old horses, with an average of 106 ± 10.3 beats per minute.

Findings: Heart Rate Variability and Age

  • The low frequency (LF) and high frequency (HF) powers, measures of heart rate variability, were found to increase with age for horses from newborn to old age.
  • Three to seven-year-old race horses were found to have the lowest heart rates and the highest LF and HF powers, with the exception of very old horses.
  • Horses over 25 years old had the highest HF powers and the lowest LF/HF ratios. Of these, 8 out of 15 horses had LF/HF ratios of less than 1.0, indicating a different autonomic balance compared to younger horses.

Interpretation and Implications

  • The findings suggest that the observed changes in heart rate and heart rate variability are likely effects of ageing in horses.
  • The distinctly low HR values and high LF and HF powers in race-trained horses aged 3 to 7 years suggest that race training may influence these physiological characteristics.
  • The unique heart rate variability in horses aged over 25 years may indicate a different autonomic balance as compared to younger horses and requires further investigation.

Cite This Article

APA
Ohmura H, Jones JH. (2017). Changes in heart rate and heart rate variability as a function of age in Thoroughbred horses. J Equine Sci, 28(3), 99-103. https://doi.org/10.1294/jes.28.99

Publication

Journal of equine science
ISSN: 1340-3516
NlmUniqueID: 9503751
Country: Japan
Language: English
Volume: 28
Issue: 3
Pages: 99-103

Researcher Affiliations

Ohmura, Hajime
  • Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan.
Jones, James H
  • School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A.

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Citations

This article has been cited 16 times.
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