The influence of desynchronised circadian rhythm on emotional contagion and reactivity: A comparative study
Authors: Anand Nirmala Subhash , Shubhangi Medha , Martínez Aarli Cristóbal Johan , García Ríos Antonio , Raniello Veronica , Rao Sakshi 
Published: November 2024

Objectives:
The objective of this study was to assess the impact of acute sleep deprivation (12 h) on emotional and autonomic reactivity and processing in nursing shift workers at KLE’s Prabhakar Kore Hospital and MRC. The impact of acute sleep deprivation on emotional behaviour in health-care personnel, especially nurses, is a topic of significant interest in the scientific community. Despite this, the existing body of literature on this topic remains relatively scarce. This is particularly important in the field of nursing, where socioemotional behaviour, irritability and volatilities are compulsory evil and an occupational hazard. This study aims to delve into the effects of acute sleep deprivation on emotional behaviour among shift-working nurses. It explores the correlation between desynchronised circadian rhythms, emotional processing, and reactivity, with a specific focus on their interaction with declarative memory. The impact of sleep deprivation on associative memory is also touched on.

Materials and Methods:
Seventy-two nursing students (III year) who were posted for night duties (8 p.m.–8 a.m.) and age- and gender-matched day-time working nurses were recruited. Following their respective shifts, they were made to fill Pittsburgh Sleep Quality Index (PSQI), Stanford Sleepiness Score and Hospital Anxiety and Depression Scale (HADS) questionnaires. To assess emotional contagion, the nurses underwent a facial affective recognition task, and to assess autonomic reactivity, heart rate variability (HRV) in the form of the root mean square of the successive difference (RMSSD) was recorded using an HRV phone tracker.

Results:
The results of our study prove that sleep deprived group (SD) nurses had poor PSQI global score (females [12 ± 7.6] and males [12.34 ± 5.4]) as compared to daytime controls (female [7 ± 4.8] and male [7.2 ± 6]). Sleep-deprived female nurses showed a tendency toward sleepiness (3.66 ± 0.24) as compared to SD male nurses, who showed greater anxiety (8 ± 1.1) on the HADS questionnaire as compared to daytime controls. During the affective facial recognition task (AFRT) for emotional contagion, the SD female nurses showed hyperarousal to negative valence emotions such as anger (4 ± 11.12) and fear (4.2 ± 9.0) as compared to controls. There was blunting toward positive valence emotions (happy) in SD (1.5 ± 11) as compared to daytime controls (2.5 ± 10.2), but no statistical change among the male SD and controls. HRV in relation to negative valence emotion to assess reactivity (anger) was associated with sympathetic activity characterised by reduced RMSSD (39 ± 7.0) in SD female nurses as compared to controls (51 ± 12.46); no statistically significant change was observed in male counterparts. There was no notable change in emotions such as surprise and disgust among SD and controls in both genders.

Conclusion:
Results obtained from our study suggest fragmented sleep quality as well as a higher incidence of morning sleepiness in night-shift workers. The AFRT showed heightened hyperarousal following a negative valence (anger and fear) Stimuli but a blunted response toward happy and sad pictures. The vagal dominance in the form of RMSSD showed a blunted response during negative valence emotions, suggesting increased sympathetic preponderance during viewing those during sleep-deprived states.