Impact of Sleep Deprivation on Autonomic Function in Office Workers: An Empirical Field Study

Thesis Abstract

Chronic sleep deprivation is increasingly prevalent among office workers and is associated with dysregulated autonomic function, contributing to elevated cardiovascular risk and impaired cognitive performance. This study addresses gaps in field-based evidence linking sleep loss to autonomic nervous system (ANS) reactivity in real-world work contexts, emphasizing objective autonomic indices alongside subjective well-being. The aim is to quantify the impact of acute and short-term sleep restriction on autonomic balance among office workers and to identify moderating factors such as job strain, caffeine intake, and chronotype. Specific objectives are (1) to assess associations between nightly sleep duration/quality and autonomic markers (heart rate variability, baroreflex sensitivity, and pupil dilation as a proxy for sympathetic arousal) across typical workdays; (2) to examine diurnal patterns of ANS activity under sleep-deprived conditions; (3) to evaluate the mediating role of perceived stress and fatigue in the sleep-autonomic relationship; and (4) to explore differential effects by sex and age strata, as well as by chronotype. A longitudinal, mixed-methods field design will be employed. The population comprises full-time office workers in a mid-sized financial services firm. A targeted sample of 320 participants will be recruited, stratified by sex and age. Objective sleep data will be collected for four weeks using wrist-worn actigraphy and daily sleep diaries to capture total sleep time, sleep efficiency, and awakenings. Autonomic function will be assessed with weekly resting heart rate variability (HRV) metrics (time-domain and frequency-domain measures RMSSD, SDNN, LF/HF ratio) and baroreflex sensitivity via noninvasive methods, complemented by real-time pupillometry during standardized cognitive tasks to index sympathetic/attentional arousal. Additional data will include cortisol awakening response as a biomarker of HPA axis activity, validated fatigue and sleepiness scales (Epworth Sleepiness Scale, Chalder Fatigue Questionnaire), and perceived stress (Perceived Stress Scale). A subset of 60 participants will participate in in-depth semi-structured interviews to contextualize quantitative findings. Quantitative analyses will employ multilevel modeling to account for within-person (daily) and between-person variability, with sleep variables entered as time-varying predictors of HRV and baroreflex measures. Regression analyses will adjust for confounders including caffeine consumption, physical activity (accelerometer-derived), body mass index, shift history, and chronotype (Morningness-Eveningness Questionnaire). Mediation analyses will test whether fatigue and perceived stress mediate the sleep–autonomic associations. Moderation analyses will examine whether sex, age, and chronotype modify these relationships. For the qualitative component, thematic analysis will be conducted on interview transcripts to identify perceived mechanisms linking sleep loss to autonomic responses, triangulated with quantitative results. Expected findings include a dose–response relationship wherein shorter sleep duration (<6 hours) and lower sleep efficiency predict reduced HRV (lower RMSSD, SDNN) and elevated LF/HF ratio, indicating sympathetic dominance. Sleep deprivation is anticipated to alter diurnal HRV sensitivity, with blunted morning HRV recovery and heightened late-afternoon sympathetic arousal. Pupillometric indicators are expected to co-vary with HRV changes, reflecting concurrent autonomic and cognitive load increases. Mediation analyses are expected to confirm fatigue and perceived stress as pathways linking sleep loss to autonomic dysregulation. Subgroup analyses may reveal greater vulnerability among older workers and evening chronotypes. The study contributes to knowledge by providing robust field-based evidence of how sleep deprivation perturbs autonomic regulation in a real-world workplace, integrating objective physiological indices with subjective experiences, and identifying modifiable factors (caffeine use, workload management) that could mitigate risk. The findings have practical implications for organizational health policies, work scheduling, and employee wellness programs, including targeted interventions to optimize sleep hygiene, chronotype-aware task assignment, and stress reduction strategies. The study concludes that even short-term sleep restriction can meaningfully disrupt autonomic balance in office workers, underscoring the need for organizational support systems to promote adequate sleep and preserve cardiovascular and cognitive health. Recommended actions include implementing flexible start times, monitoring workloads to minimize sleep debt accumulation, and offering education on sleep health and stress management, with future research suggested to examine longitudinal health outcomes and intervention effectiveness.