Impact of sleep deprivation on autonomic cardiovascular regulation in healthy adults: A longitudinal study

Project Abstract

Sleep deprivation profoundly disrupts autonomic cardiovascular regulation, with consequences that extend beyond transient fatigue to measurable alterations in heart rate variability, blood pressure responses, and vascular endothelial function. This longitudinal study investigates the cardio-autonomic adaptations to sustained sleep restriction in healthy adults over a 12-week period, integrating continuous ambulatory monitoring, controlled laboratory assessments, and subjective sleep metrics. A cohort of 120 participants, aged 20–35 years, underwent randomized alternating weeks of sufficient sleep (?7.5 hours) and sleep restriction (?5 hours), enabling within-subject comparisons across two distinct phases. Primary outcomes included autonomic balance indices derived from high-resolution heart rate variability (HRV) analyses in time, frequency, and non-linear domains, alongside baroreflex sensitivity estimated by sequence and transfer function methods. Secondary outcomes encompassed resting blood pressure, nocturnal dipping patterns, and sympathetic reactivity assessed through cold pressor testing and postural change protocols. Cognitive and mood assessments were administered to elucidate mediator effects of sleep loss on autonomic function, while inflammatory markers (CRP, IL-6) and endothelial function (flow-mediated dilation) provided mechanistic insights into vascular regulation under sleep-restricted conditions. Methodologically, repeated-measures ANOVA and mixed-effects models were employed to parse within- and between-subject variations across phases, controlling for age, sex, BMI, caffeine intake, and physical activity. Time-series analyses characterized circadian misalignment and its relation to HRV non-stationarity. Subgroup analyses explored sex-specific responses and the influence of baseline autonomic tone on vulnerability to sleep deprivation. The study also implemented a stratified random sampling to ensure representation of morning and evening chronotypes, assessing whether chronotype modulates the magnitude of autonomic disruption. Preliminary findings indicate that sleep restriction reduces overall HRV, particularly in the high-frequency band, suggesting diminished parasympathetic activity, while low-frequency components show ambiguous changes indicating altered sympathetic modulation or baroreflex coupling. Baroreflex sensitivity demonstrated a progressive decline during extended sleep loss, correlating with attenuated nocturnal blood pressure dipping and elevated daytime systolic pressures. Postural challenges elicited exaggerated sympathetic surges in the sleep-restricted state, and cold pressor responses were amplified, indicating heightened vascular reactivity. The data revealed a dose-response relationship between the degree of sleep restriction and autonomic perturbation, with partial recovery observed during the compensatory sleep periods, albeit incomplete within the 12-week window. Associations emerged linking autonomic disruption to subjective fatigue, impaired executive function, and mood disturbances, with inflammatory and endothelial markers partially mediating these relationships. The study contributes to the understanding of how chronic sleep deprivation alters autonomic control of the cardiovascular system in healthy adults, delineating temporal patterns, potential compensatory mechanisms, and individual susceptibility factors. Implications for occupational health, shift-work policies, and public safety underscore the need for targeted interventions to mitigate sleep-related cardiovascular risk. Future work will extend follow-up to assess long-term reversibility and explore pharmacologic or behavioral strategies to restore autonomic equilibrium in sleep-impaired populations.

Project Overview

What This Project Is About

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This project looks at how not getting enough sleep affects how the body controls heart and blood vessel activity in healthy adults over time. It compares people who sleep well with those who experience short or disrupted sleep and tracks changes in cardiovascular regulation, which is how the body keeps blood pressure and heart rate stable.

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The Problem It Addresses

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Objectives of the Project

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1. Describe how sleep duration and quality relate to autonomic control indicators over time.
2. Compare autonomic response between well-rested and sleep-deprived individuals.
3. Identify the most sensitive measures of autonomic changes linked to sleep loss.
4. Assess potential differences due to age, sex, and lifestyle factors.

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What You Will Do Step by Step

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1. Recruit healthy adult volunteers and classify by sleep patterns.
2. Collect baseline cardiovascular data (heart rate, blood pressure, variability) during awake periods.
3. Implement a sleep manipulation protocol and monitor sleep using actigraphy and logs.
4. Periodically measure autonomic indicators during sleep and wakefulness.
5. Analyze data to detect changes over time and between groups.
6. Interpret findings in the context of existing literature and potential mechanisms.

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Expected Outcome