Cardiac cycle length variability in ponies at rest and during exercise

Rugh, K. S.; Jiang, Benyu; Hatfield, D.; Garner, H. E.; Hahn, A W

doi:10.1152/jappl.1992.73.4.1572

Cited by 8 publications

(5 citation statements)

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“…By 1910, Heinrich E. Hering (1866–1948) could write that “ it is known with breathing that a demonstrable lowering of heart rate … is indicative of the function of the vagi ” (Hering, 1910). Hamlin et al (1966) convincingly demonstrated that RSA in the dog resulted from activation of the vagal nerves, an observation that has been confirmed in other mammalian species (cats: Chess et al, 1975; Yongue et al, 1982; rats: McCabe et al, 1985; Cerutti et al, 1991; horse and ponies: Hamlin et al, 1972; Rugh et al, 1992), including human (Davies and Neilson, 1967; Melcher, 1976; Hirsch and Bishop, 1981; Selman et al, 1982; Eckberg, 1983). Sympathetic neural activation was also found to contribute significantly periodic arterial pressure changes (Guyton and Harris, 1951; Preiss et al, 1975).…”

Section: Historical Overviewmentioning

confidence: 91%

Heart Rate Variability ? A Historical Perspective

Billman¹

2011

Front. Physio.

590

521

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Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R–R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the “Physician’s Pulse Watch” (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV.

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Section: Historical Overviewmentioning

confidence: 91%

Heart Rate Variability ? A Historical Perspective

Billman¹

2011

Front. Physio.

590

521

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“…Only limited investigations of HRV in the horse have been performed. Variation in cardiac cycle length in ponies has been studied in the time domain at rest and at exercise (Rugh et al 1992). Clément and Barrey (1995a,b) used power spectral analysis of HRV to examine autonomic contributions to emotionality in a horse.…”

Section: Introductionmentioning

confidence: 99%

Frequency domain analysis of heart rate variability in horses at rest and during exercise

Physick‐Sheard

Marlin

Thornhill

et al. 2000

Equine Veterinary Journal

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Summary The pattern of variation in heart rate on a beat‐to‐beat basis contains information concerning sympathetic (SNS) and parasympathetic (PNS) contributions to autonomic nervous system (ANS) modulation of heart rate (HR). In the present study, heart period (RR interval) time series data were collected at rest and during 3 different treadmill exercise protocols from 6 Thoroughbred horses. Frequency and spectral power were determined in 3 frequency bands: very low (VLF) 0–≤ 0.01, low (LO) >0.01–≤ 0.07 and high (HI) >0.07–≤ 0.5 cycles/beat. Indicators of sympathetic (SNSI = LO/HI) and parasympathetic (PNSI = HI/TOTAL) activity were calculated. Power in all bands fell progressively with increasing exercise intensity from rest to trot. At the gallop VLF and LO power continued to fall but HI power rose. SNSI rose from rest to walk, then fell with increasing effort and was lowest at the gallop. PNSI fell from rest to walk, then rose and was highest at the gallop. Normalised HI power exceeded combined VLF and LO power at all gaits, with the ratio HI to LO power being lowest at the walk and highest at the gallop. ANS indicators showed considerable inter‐horse variation, and varied less consistently than raw power with increasing physical effort. In the horses studied, the relationship between power and HR changed at exercise intensities associated with heart rates above approximately 120–130 beats/min. At this level, humoral and other non‐neural mechanisms may become more important than autonomic modulation in influencing heart rate and heart rate variability (HRV). HRV at intense effort may be influenced by respiratory‐gait entrainment, energetics of locomotion and work of breathing. HRV analysis in the frequency domain would appear to be of potential value as a noninvasive means of assessing autonomic modulation of heart rate at low exercise intensities, only. The technique may be a sensitive method for assessing exercise response to experimental manipulations and disease states.

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“…This study focused on various parameters since literature relating to stress indicators reliability in horses is quite fragmentary (Baucus et al, 1990;Colborn et al, 1991;Rugh et al, 1992;McCarthy et al, 1993;Canali et al, 1996;Thayer et al, 1997;Wolff et al, 1997;McGreevy and Nicol, 1998;Anderson et al, 1999;Minero et al, 1999;Vierin et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

A note on reaction to novel stimulus and restraint by therapeutic riding horses

Minero

Zucca

2006

Applied Animal Behaviour Science

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Little research has been done to measure reactivity objectively in therapeutic riding horses (TRH). As individual reactivity and chronic stress could be assessed by exposing animals to acute, novel stressors, the authors of this work aimed at comparing reactions of TRHs and jumping horses (JH) to two challenges. Four TRHs and four JHs were exposed to a restraint covering their head with a hood for 1 hour and to a startling stimulus (a 40 cm long, red and white synthetic holiday garland shaken with a rustling noise inside the box). Heart rate (HR) and heart rate variability (HRV) were recorded continuously and telemetrically, the reaction was video-recorded and analysed with a software for behavioural analysis. Blood samples were collected before and after each challenge to determine lymphocyte proliferation and other biochemical parameters. Horses spent most of the time immobile during the challenges (p<0.05). TRHs had a significantly higher average basal HR than JH (p<0.05), probably due to their better condition. HR varied among different behaviours during the restraint (p<0.05): the average HR during "pawing" was higher than during other behaviours (p<0.005). A significant decrease in the proliferation of lymphocytes in samples taken after the removal of the hood (p<0.05) was found, while the other stress related parameters didn't vary significantly after the challenges. The authors conclude that TRHs did not react less than JHs to the new stimuli and this should be taken into consideration while planning their daily work and management.

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Cardiac cycle length variability in ponies at rest and during exercise

Cited by 8 publications

References 0 publications

Heart Rate Variability ? A Historical Perspective

Heart Rate Variability ? A Historical Perspective

Frequency domain analysis of heart rate variability in horses at rest and during exercise

A note on reaction to novel stimulus and restraint by therapeutic riding horses

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