Commonly experienced acute and cumulative 8-hour sleep loss differentially affect simulated driving during a night-time to early-morning commute: a randomized controlled crossover trial

Abstract Sleep loss is a major contributor to traffic accidents, yet the differential effects of two common real-world patterns of sleep loss, acute total sleep deprivation and cumulative sleep restriction producing an equivalent 8-h sleep loss, on vehicle control remain poorly quantified. Leveraging tightly controlled sleep manipulation and highly immersive driving simulation, we directly compared the effects of different patterns of sleep loss under naturalistic driving conditions. Twenty healthy male participants completed a randomized within-subject crossover sleep design, comprising normal sleep, cumulative sleep restriction (four nights 2 h reduced sleep per night), and acute total sleep deprivation (one night without sleep), each followed by a simulated nighttime-to–early-morning commute. Acute total sleep deprivation produced pronounced impairments in vehicle control. Most prominently, lateral control deteriorated within 4–6 min under acute deprivation, with impairments comparable to those reported at high blood alcohol concentrations (1.2–1.4 g/L). Steering instability and integrated driving performance showed convergent deterioration. In contrast, cumulative sleep restriction resulted in smaller and less consistent changes, while vigilance task performance and speed variability were comparatively preserved across all conditions. Despite graded increases in subjective sleepiness across conditions, cumulative sleep restriction produced only limited changes in driving performance, whereas acute sleep deprivation produced a disproportionate risk to driving safety by selectively and rapidly degrading operational vehicle control. These findings, obtained under ecologically relevant sleep and driving conditions, underscore functional and potentially physiological differences between acute and cumulative sleep loss and, practically, highlight the importance of distinguishing between them when considering sleep-loss–related driving impairment and safety risk. Clinical Trials–name, URL, and registration: Clinical Trial name: Study of Identification of Metabolomics-based Sleepiness Markers for Risk Prevention and Traffic Safety—ClinicalTrials.gov Identifier NCT05585515, released on 18.10.2022, https://clinicaltrials.gov/study/NCT05585515; Swiss National Clinical Trial Portal SNCTP000005089, registered on 12.08.2022, https://www.humanforschung-schweiz.ch/de/studiensuche/studien-detail/58930. IRB Statement: This study was approved by the local ethics committee (Kantonale Ethikkommission Zürich, reference number 2022–01273). No identifying images or other personal or clinical details of participants are presented here or will be presented in reports of the trial results. Informed consent materials are available from the corresponding author on request. We confirm all methods were performed in accordance with the Declaration of Helsinki and its later amendments.