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Updated: Jun 28, 2026
Autonomic Function Following Concussion in Youth Athletes: An Exploration of Heart Rate Variability Using 24-hour Recording Methodology
Published on: September 21, 2018
Monday-to-Friday workweek trajectory of ventricular repolarization and heart rate variability in apparently stable
1Department of Cardiology, Cihanbeyli State Hospital, Konya, Türkiye.
Background:
Cardiovascular events show temporal clustering at the beginning of the workweek, but whether ventricular repolarization and autonomic regulation follow a Monday-to-Friday workweek trajectory remains insufficiently defined. We evaluated within-subject changes in electrocardiographic repolarization markers and heart rate variability (HRV) in apparently stable adults without overt cardiovascular disease.
Methods:
In this repeated-measures study, 85 participants underwent serial resting 12‑lead electrocardiography and five consecutive 24-h Holter recordings from Monday through Friday. Ventricular repolarization indices, including T-peak-to-T-end (Tp-e), QT, QTc, QTcF, Tp-e/QT, and Tp-e/QTc, and HRV parameters, including SDNN, RMSSD, and pNN50, were assessed. Monday-to-Friday changes were evaluated using repeated-measures ANOVA and linear mixed-effects models with participant-specific random intercepts. Sequential models were adjusted for age, sex, mean 24-h heart rate, perceived stress, and physical activity.
Results:
Tp-e values were highest on Monday and progressively decreased toward Friday (p < 0.001). In contrast, SDNN, RMSSD, and pNN50 increased over the same observation window, suggesting improved vagal modulation. Raw QT intervals lengthened as mean heart rate declined, whereas corrected QT indices showed modest, non-monotonic variation. In fully adjusted mixed-effects models, the Monday-to-Friday weekday variable remained independently associated with Tp-e. Higher perceived stress and mean heart rate were associated with longer Tp-e, whereas greater physical activity was associated with shorter Tp-e.
Conclusions:
In apparently stable adults, repolarization heterogeneity and autonomic indices showed a Monday-to-Friday within-subject workweek trajectory. These findings should be interpreted as observational workweek-related associations, not as evidence of a complete weekly cycle, weekend recovery, or causal linkage with cardiovascular events.
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