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Correlation of heart rate variability and circadian markers in humans

Philippe Boudreau1, Guy Dumont, N M K Ng Ying Kin

  • 1Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada. philippe.boudreau@douglas.mcgill.ca

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference
|January 19, 2012
PubMed

Insights

Morning cardiovascular events are linked to circadian rhythms. Heart rate variability and hormone levels show distinct patterns, suggesting a role for autonomic nervous system shifts in this increased risk.

Area of Science:

  • Cardiovascular physiology
  • Chronobiology
  • Autonomic nervous system function

Background:

  • Adverse cardiovascular events show a higher frequency in the morning hours.
  • Circadian variations in physiological processes, including cardiovascular regulation, are well-documented.
  • Understanding these rhythms may explain morning cardiovascular risk.

Purpose of the Study:

  • To investigate the correlation between heart rate (HR) and heart rate variability (HRV) with circadian rhythms of cortisol and melatonin.
  • To analyze autonomic modulation markers (LF, HF, LF:HF ratio) in relation to hormonal rhythms.

Main Methods:

  • Utilized an ultradian sleep-wake cycle (USW) procedure.
  • Measured heart rate (HR) and heart rate variability (HRV) components (LF, HF, LF:HF ratio).
  • Assessed salivary cortisol and urinary 6-sulfatoxy-melatonin (UaMt6s) levels cross-correlated with HRV parameters.

Main Results:

  • Mean RR interval was phase-advanced relative to cortisol and UaMt6s.
  • Parasympathetic modulation (HF power) was phase-advanced to cortisol and in-phase with UaMt6s.
  • Sympathovagal balance (LF:HF ratio) showed no significant lag relative to cortisol and UaMt6s.

Conclusions:

  • Circadian rhythms of HR and HRV correlate with hormonal rhythms (cortisol, melatonin).
  • Autonomic nervous system activity shifts, with sympathetic dominance in the morning, may contribute to increased cardiovascular risk.
  • These findings highlight the importance of circadian influences on cardiovascular health.

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