Sleep Deprivation-Induced Alterations in Mood States Correlate with Changes in Spontaneous Brain Activity

Modern warfare places soldiers under unique conditions, requiring them to operate on irregular schedules in extreme environments, resulting in unprecedented physical and psychological challenges. Prolonged duty, nighttime operations, intense combat, and dynamic work demands often reduce sleep duration and quality. Additionally, battlefield noise and harsh environmental conditions contribute to difficulty falling asleep and maintaining sleep. Consequently, numerous soldiers endure severe sleep deprivation; some even develop sleep disorders. Within military training, sleep deprivation can engender many adverse consequences, with mood variability being one of the prominent outcomes. Soldiers frequently manifest sensations of profound fatigue, heightened irritability, acute anxiety, and pronounced despondency, all of which correlate with insufficient sleep. Sleep insufficiency undermines mood stability and diminishes the capacity to cope effectively with conflicts and stressors, constituting a latent threat to soldiers’ psychological well-being and work performance. Sleep is crucial in mood regulation and its impact on psychological health. In-depth research into the mechanisms underlying the relationship between sleep deprivation and mood can offer profound insights into improving soldiers’ mood states and work efficiency. Furthermore, it can provide valuable data support for human-computer interaction design. This study aimed to investigate the impact of sleep deprivation on the mood states of healthy participants and the correlational relationship between alterations in mood states under the influence of sleep deprivation and spontaneous electroencephalographic (EEG) activity. The research involved a 36-h complete sleep deprivation experiment conducted on 30 male participants aged between 19 and 30. Mood states were assessed at baseline, 24 h into sleep deprivation, and 36 h into sleep deprivation using the Profile of Mood States (POMS) questionnaire, and concurrent resting-state EEG data were recorded. Statistical analysis was conducted on various mood factors assessed by the POMS questionnaire and the relative power of spontaneous brainwave rhythms, exploring the degree of association between mood states and spontaneous brainwave rhythms under sleep deprivation. The results of the POMS questionnaire showed significant differences (p < 0.05) in CB, AH, FI, and VA scores between the sleep deprivation group and the baseline group. Moreover, post-hoc comparisons revealed remarkable variations (p < 0.001) in CB, AH, FI, and VA scores at 24 h and 36 h of complete sleep deprivation compared to the baseline. Additionally, there were no meaningful differences in CB, AH, and FI levels between 24 and 36 h of complete sleep deprivation. In terms of the relative power of spontaneous EEG, theta (θ) and alpha (α) waves showed notable changes (p < 0.05) in various brain regions compared to baseline, indicating a marked influence of sleep deprivation on these brainwave frequencies. Moreover, gamma (γ) wave activity in the frontal and parietal lobes also exhibited significant changes (p < 0.05). However, delta (δ) and beta (β) wave frequencies did not show material impact in various brain regions. These findings emphasize the differential impact of sleep deprivation on different EEG rhythms, contributing to a more comprehensive understanding of the effects of sleep deprivation on brainwave activity. Correlation analysis revealed a certain degree of association between alterations in mood states and specific brainwave activities in particular brain regions. Under the conditions of 24 h of sleep deprivation for negative mood, CB exhibited a substantial positive correlation with the relative power of theta frequency bands in the parietal lobe (p < 0.05) and a clear negative correlation with the relative power of gamma frequency bands in the frontal and parietal lobes (p < 0.05). Under 36 h of sleep deprivation, for positive mood, VA showed a marked positive correlation with the relative power of theta frequency bands in the frontal, central, and parietal lobes (p < 0.05) and a convincing negative correlation with the relative power of alpha frequency bands in the frontal lobe (p < 0.05). The research findings furnish neurophysiological evidence of sleep's impact on mood, offering support for improving individuals’ mental health and enhancing work performance, especially concerning soldiers operating in challenging combat environments.