Diurnal Heart Rate Range and Heart Rate Excursions - Novel Characterizations of Wearable Heart Rate Variability With an Application to Aging

Oct 12, 2026

Wearable heart rate monitors record minute-level data continuously, but standard summaries such as resting HR and heart rate reserve discard within-day dynamics. The study introduces diurnal heart rate range (dHRR) to quantify time-of-day-specific HR range across repeated days and heart rate excursions (HREs) to characterize individual HR rises/declines by amplitude and duration. Minute-level HR from 750 Baltimore Longitudinal Study of Aging participants was modeled across the 24-hour cycle using percentile curves and regression methods.

LanguageEnglish

CategoryGeneral

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Pages19

Reading Time7 min

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Abstract

Background

Methods

Results

Conclusions

Introduction

medRxiv preprint doi: [https://doi.org/10.64898/2026.09.29.26364190](https://doi.org/10.64898/2026.09.29.26364190); this version posted October 5, 2026. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . Diurnal Heart Rate Range and Heart Rate Excursions: Novel Characterizations of Wearable Heart Rate Variability With an Application to Aging Authors: Samuel D. Fansler1 , Owen Yoo2 , Shuiqing Han3 , Luigi Ferrucci4 , Eleanor M. Simonsick4 , Jennifer A. Schrack5 , Irina Gaynanova*6 , Vadim Zipunnikov* 1 *Co-senior authors Affiliations: 1. Johns Hopkins University Bloomberg School of Public Health, Department of Biostatistics 2. University of Michigan, College of Literature, Science, and the Arts, Department of Statistics and Data Science 3. University of Michigan, College of Literature, Science, and the Arts, Department of Mathematics 4. Intramural Research Program, National Institute on Aging 5. Johns Hopkins University Bloomberg School of Public Health, Department of Epidemiology 6. University of Michigan School of Public Health, Department of Biostatistics NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: [https://doi.org/10.64898/2026.09.29.26364190](https://doi.org/10.64898/2026.09.29.26364190); this version posted October 5, 2026. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . Abstract Background Wearable heart rate (HR) monitors collect minute-level HR continuously across days, yet these data are commonly reduced to scalars such as resting HR (RHR) and heart rate reserve (HRR), defined as the difference between maximum HR and RHR. This discards two dimensions of within-day HR dynamics: how HR range varies across the day and the magnitude and duration of individual HR rises and declines. We introduce diurnal heart rate range (dHRR), a time-ofday-specific measure of HR range across repeated days, and heart rate excursions (HREs), individual HR rises and declines characterized by amplitude and duration. Methods We analyzed minute-level HR from 750 participants in the Baltimore Longitudinal Study of Aging (mean [SD] age, 66 [12] years) . We estimated the 5th, 50th, and 95th HR percentiles at each minute of the 24-hour cycle across repeated days, defining diurnal HR (dHR) as the median curve and dHRR as the 95th minus 5th percentile curve. A moving-average algorithm segmented HR into HREs. Function-on-scalar regression modeled dHR and dHRR by age, sex,and BMI across the day; local polynomial regression examined age and sex differences in HRR and HREs. Results Conventional HRR decreased with age, indicating a smaller overall observed HR range. Agerelated differences in dHR varied substantially across the day: between ages 40 and 80, fitted dHR was approximately 2 bpm lower at 3:00 AM but 8 bpm lower at 6:00 PM. dHRR showed that this contraction was not uniform across the day: the evening peak near 6:00 PM at younger ages was largely absent by age 70, while the morning peak shifted from approximately 9:00 AM toward noon. At the event level, HREs showed two parallel age-related changes: between ages 40 and 80, mean excursion amplitude decreased from approximately 40 to 32 bpm, while mean excursion duration increased from approximately 90 to 104 minutes. Conclusions Aging was characterized by a smaller global HR range, compression and reorganization of HR range across the day, and smaller, longer-lasting HREs. dHRR and HREs provide complementary views of the diurnal organization and event-level dynam

FAQs

What limitations of conventional HR summaries does the study address?

Conventional measures like resting HR and heart rate reserve reduce minute-level wearable data to scalars, discarding how HR range changes across the day and the amplitude and duration of individual HR rises and declines.

What are dHRR and HREs in this work?

dHRR (diurnal heart rate range) is a time-of-day-specific measure derived from 95th minus 5th HR percentiles across repeated days, while HREs describe individual HR rises and subsequent declines with amplitude and duration.

How does aging relate to the proposed HR metrics?

Aging is associated with a smaller global HR range, compression and reorganization of HR range across the day, and HREs that are smaller in amplitude but longer in duration.

Oct 12, 2026

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