Linking Multi-Night Sleep Heart Rate to Vigilance: Insights from Antarctic Field Research

This study investigated the associations between sleep heart rate, sleep duration, and Psychomotor Vigilance Task performance using repeated measures data collected during an Antarctic expedition. Data were collected without inducing sleep restriction, reflecting naturalistic sleep patterns. Results revealed that a higher mean sleep heart rate on the preceding night was significantly associated with slower reaction time on the PVT. In contrast, association with sleep duration did not reach statistical significance. Interestingly, being a first-time participant was a significant predictor of faster reaction times, whereas age was not, suggesting that the observed performance differences are more likely attributable to an adaptive response to environmental novelty rather than age-related cognitive variation. Night-to-night variations in sleep parameters were not significant predictors. These findings suggest that mean sleep heart rate may serve as a more effective metric than sleep duration for predicting vigilant performance in real-life contexts without induced sleep deprivation. Despite limitations of a modest sample size and data from a single expedition, this study offers novel insights into optimizing human performance in extreme environments and informing risk mitigation strategies. Future research should replicate these findings across diverse contexts and integrate longitudinal physiological and psychological assessments for a comprehensive understanding of performance variability.