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Published on: September 21, 2018
Heart Rate Variability and Chronotype in Young Adult Men
Joseph D Vondrasek1, Shaea A Alkahtani2, Abdulrahman A Al-Hudaib2
1Department of Health Sciences and Kinesiology, Biodynamics and Human Performance Center, 11935 Abercorn St. Savannah, Georgia Southern University, Savannah, GA 31419, USA.
Insights
Morning heart rate variability (HRV) predicts its daily change, with higher morning values leading to greater diurnal variation. Chronotype did not influence this relationship in healthy young men.
Area of Science:
- Cardiovascular Physiology
- Chronobiology
- Autonomic Nervous System Function
Background:
- Heart rate variability (HRV) exhibits diurnal patterns, but its relationship with chronotype and the magnitude of daily variation in healthy individuals remains unclear.
- Understanding these associations is crucial for assessing cardio-autonomic health and circadian rhythmicity.
Purpose of the Study:
- To investigate the association between morning heart rate variability (HRV) and its diurnal change in healthy men.
- To examine the influence of chronotype, assessed via the Morningness-Eveningness Questionnaire (MEQ), on morning HRV and its diurnal variation.
Main Methods:
- Twenty-three healthy men underwent resting electrocardiograms in the morning and evening on separate days.
- Key HRV parameters, including mean RR interval, RMSSD, and SDNN, were calculated.
- The Morningness-Eveningness Questionnaire (MEQ) was used to determine chronotype.
Main Results:
- Morning HRV parameters (RMSSD and SDNN) were significantly higher than evening values.
- Morning HRV metrics were strongly associated with both absolute and relative diurnal changes in HRV.
- No significant associations were found between morning HRV parameters and MEQ-derived chronotypes.
Conclusions:
- Higher morning HRV is a key determinant of greater diurnal variation in HRV among healthy young men.
- Chronotype does not appear to influence the diurnal amplitude of HRV in this population.
- Interventions aimed at improving basal morning HRV may enhance cardio-autonomic circadian profiles.
Abstract:
Whether morning heart rate variability (HRV) predicts the magnitude of its circadian variation in the absence of disease or is influenced by chronotype is unclear. We aimed to quantify associations between (1) morning HRV and its diurnal change, and (2) morning HRV and a Morningness−Eveningness Questionnaire (MEQ)-derived chronotype. Resting electrocardiograms were obtained in the morning and evening on separate days in a counterbalanced order to determine the mean RR interval, root mean square of successive differences (RMSSD), and standard deviation of normal-to-normal RR intervals (SDNN) in 23 healthy men (24.6 ± 3.4 yrs; body mass index: 25.3 ± 2.8 kg/m2). The MEQ was completed during the first laboratory visit. Morning RMSSD and SDNN were significantly higher (Ps < 0.05) than evening values. Morning RMSSD and SDNN were associated with their absolute (Ps < 0.0001), and relative diurnal changes (Ps < 0.01). No associations were observed between HRV parameters and the MEQ chronotypes (Ps > 0.09). Morning HRV was a stronger determinant of its evening change than chronotype. Greater diurnal variation in HRV was dependent on higher morning values. Strategies to improve basal HRV may therefore support healthier cardio-autonomic circadian profiles in healthy young men.
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