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The Dynamics of Heart Rate Asymmetry and Situational Sleepiness from Evening to Night: The Role of Daytime Sleepiness
Faculty of Social Sciences, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
Biology 2024, 13(10), 794; https://doi.org/10.3390/biology13100794
Submission received: 20 August 2024
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Revised: 30 September 2024
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Accepted: 2 October 2024
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Published: 3 October 2024
(This article belongs to the Special Issue Cardiovascular Autonomic Function: From Bench to Bedside)
Simple Summary
This study examined how both daytime and situational sleepiness are associated with heart rate asymmetry (HRA) from evening to night. Fifty participants were divided into two groups based on their levels of daytime sleepiness: ‘Lower Normal’ and ‘Higher Normal.’ HRA and situational sleepiness were assessed at 8 P.M., 9 P.M., and 10 P.M. The results showed that individuals with higher daytime sleepiness had lower HRA by 10 P.M., indicating reduced parasympathetic activity and impaired autonomic regulation. Significant correlations were also found between situational sleepiness and HRA metrics in the ‘Higher Normal’ group, particularly in measures of short-term and long-term heart rate variability. These findings suggest that monitoring HRA could help detect drowsiness and manage fatigue, especially in settings where maintaining alertness is critical, such as driving or shift work.
Abstract
The relationship between daytime sleepiness and heart rate asymmetry (HRA) during the transition from evening to night is crucial for understanding autonomic regulation and its implications for alertness. This study aims to investigate how daytime sleepiness influences HRA dynamics from evening to night and how situational sleepiness correlates with HRA metrics. HRA metrics were calculated at 8 P.M., 9 P.M., and 10 P.M. in 50 participants, categorized into ‘Lower Normal’ and ‘Higher Normal’ daytime sleepiness groups based on Epworth Sleepiness Scale (ESS) scores. Situational sleepiness was assessed using the Karolinska Sleepiness Scale (KSS) and Stanford Sleepiness Scale (SSS). The results demonstrated that individuals with ‘Higher Normal’ daytime sleepiness exhibited lower HRA metrics at 10 P.M. compared to those with ‘Lower Normal’ daytime sleepiness, supporting the suggestion that higher daytime sleepiness correlates with reduced parasympathetic activity and diminished autonomic responsiveness. Significant negative correlations between situational sleepiness and HRA metrics were observed in the ‘Higher Normal’ group, particularly with the SSS. Therefore, increased daytime sleepiness affects HRA dynamics by decreasing parasympathetic activity and altering autonomic regulation at the beginning of the biological night (10 P.M.). These findings suggest potential applications for enhancing drowsiness detection and managing fatigue in safety-critical environments.
