Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability

Research output: Contribution to journalArticle

176 Citations (Scopus)

Abstract

The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by 'coarse-graining spectral analysis' (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (P(t)) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high- frequency (0.15-0.8 Hz) components, from which low-frequency and high- frequency power (P(l) and P(h), respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by P(h)/P(t) and P(l)/P(h), respectively. From the fractal component, the fractal dimension (D(F)) and the spectral exponent (β) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (V̇O(2 peak)). Conversely, the SNS indicator initially increased at 50-60% V̇O(2 peak) (P < 0.05) and further increased significantly (P < 0.05) at >60% V̇O(2 peak) when there were also more pronounced increases in NE and E. The decreased PNS and the increased SNS indicators during exercise were accompanied by an increase in β (a decrease in D(F)) to the level of β > 2 (D(F) < 2). These results suggested that changes in the fractal component in HRV might be coupled to those in sympathovagal balance during physical exercise.

Original languageEnglish
Pages (from-to)875-881
Number of pages7
JournalJournal of Applied Physiology
Volume74
Issue number2
Publication statusPublished - 1993

Fingerprint

Fractals
Heart Rate
Exercise
Norepinephrine
Plasma Gases
Architectural Accessibility
Plasma Exchange
Autonomic Nervous System
Sympathetic Nervous System
Epinephrine

Keywords

  • autonomic nervous system
  • parasympathetic nervous system
  • sympathetic nervous system

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability. / Nakamura, Yoshio; Yamamoto, Y.; Muraoka, Isao.

In: Journal of Applied Physiology, Vol. 74, No. 2, 1993, p. 875-881.

Research output: Contribution to journalArticle

@article{8683ade6391b4ebebe2674b6b362c02b,
title = "Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability",
abstract = "The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by 'coarse-graining spectral analysis' (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (P(t)) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high- frequency (0.15-0.8 Hz) components, from which low-frequency and high- frequency power (P(l) and P(h), respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by P(h)/P(t) and P(l)/P(h), respectively. From the fractal component, the fractal dimension (D(F)) and the spectral exponent (β) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50{\%} of peak oxygen uptake (V̇O(2 peak)). Conversely, the SNS indicator initially increased at 50-60{\%} V̇O(2 peak) (P < 0.05) and further increased significantly (P < 0.05) at >60{\%} V̇O(2 peak) when there were also more pronounced increases in NE and E. The decreased PNS and the increased SNS indicators during exercise were accompanied by an increase in β (a decrease in D(F)) to the level of β > 2 (D(F) < 2). These results suggested that changes in the fractal component in HRV might be coupled to those in sympathovagal balance during physical exercise.",
keywords = "autonomic nervous system, parasympathetic nervous system, sympathetic nervous system",
author = "Yoshio Nakamura and Y. Yamamoto and Isao Muraoka",
year = "1993",
language = "English",
volume = "74",
pages = "875--881",
journal = "Journal of Applied Physiology Respiratory Environmental and Exercise Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "2",

}

TY - JOUR

T1 - Autonomic control of heart rate during physical exercise and fractal dimension of heart rate variability

AU - Nakamura, Yoshio

AU - Yamamoto, Y.

AU - Muraoka, Isao

PY - 1993

Y1 - 1993

N2 - The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by 'coarse-graining spectral analysis' (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (P(t)) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high- frequency (0.15-0.8 Hz) components, from which low-frequency and high- frequency power (P(l) and P(h), respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by P(h)/P(t) and P(l)/P(h), respectively. From the fractal component, the fractal dimension (D(F)) and the spectral exponent (β) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (V̇O(2 peak)). Conversely, the SNS indicator initially increased at 50-60% V̇O(2 peak) (P < 0.05) and further increased significantly (P < 0.05) at >60% V̇O(2 peak) when there were also more pronounced increases in NE and E. The decreased PNS and the increased SNS indicators during exercise were accompanied by an increase in β (a decrease in D(F)) to the level of β > 2 (D(F) < 2). These results suggested that changes in the fractal component in HRV might be coupled to those in sympathovagal balance during physical exercise.

AB - The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by 'coarse-graining spectral analysis' (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (P(t)) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high- frequency (0.15-0.8 Hz) components, from which low-frequency and high- frequency power (P(l) and P(h), respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by P(h)/P(t) and P(l)/P(h), respectively. From the fractal component, the fractal dimension (D(F)) and the spectral exponent (β) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (V̇O(2 peak)). Conversely, the SNS indicator initially increased at 50-60% V̇O(2 peak) (P < 0.05) and further increased significantly (P < 0.05) at >60% V̇O(2 peak) when there were also more pronounced increases in NE and E. The decreased PNS and the increased SNS indicators during exercise were accompanied by an increase in β (a decrease in D(F)) to the level of β > 2 (D(F) < 2). These results suggested that changes in the fractal component in HRV might be coupled to those in sympathovagal balance during physical exercise.

KW - autonomic nervous system

KW - parasympathetic nervous system

KW - sympathetic nervous system

UR - http://www.scopus.com/inward/record.url?scp=0027409465&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027409465&partnerID=8YFLogxK

M3 - Article

C2 - 8458809

AN - SCOPUS:0027409465

VL - 74

SP - 875

EP - 881

JO - Journal of Applied Physiology Respiratory Environmental and Exercise Physiology

JF - Journal of Applied Physiology Respiratory Environmental and Exercise Physiology

SN - 8750-7587

IS - 2

ER -