Sleep deficiency, operational fatigue and the interplay of compromising factors: Analysis to aid in fatigue management

Epigenetics of Homocystinuria, Hydrogen Sulfide, and Circadian Clock Ablation in Cardiovascular-Renal Disease

Morning-time heart attacks are associated with an ablation in the sleep-time dip in blood pressure, the mechanism of which is unknown. The epigenetic changes are the hallmark of sleep and circadian clock disruption and homocystinuria (HHcy). The homocystinuria causes ablation in the dip in blood pressure during sleep. Interestingly, HHcy is generated during the epigenetic gene turning off and turning on (i.e., imprinting) by methylation of the DNA promoter. The mitochondrial sulfur metabolism by 3-mercaptopyruvate sulfur transferase (3MST), ATP citrate lyase (ACYL), and epigenetic rhythmic methylation are regulated by folate 1-carbon metabolism (FOCM), i.e., the methionine (M)-SAM-SAH-Hcy, adenosine, and uric acid cycle. Epigenetic gene writer (DNMT), gene eraser (TET/FTO), and editor de-aminase (ADAR) regulate the rhythmic, i.e., reversible methylation/demethylation of H3K4, H3K9, H4K20, m6A, and m5C. The mitochondrial ATP citrate cycle and creatine kinase (CK) regulate chromatin transcription, maturation, and accessibility as well as muscle function. The transcription is regulated by methylation. The maturation and accessibility are controlled by acetylation. However, it is unclear whether a high fat dysbiotic diet (HFD) causes dysrhythmic expression of the gene writer, eraser, and editor, creating hyperuricemia and cardiac and renal dysfunction. We hypothesized that an HFD increases the gene writer (DNMT1) and editor (ADAR), decreases the eraser (TET/FTO), and increases uric acid to cause chronic diseases. This increases the levels of H3K4, H3K9, H4K20, m6A, and m5C. Interestingly, the DNMT1KO mitigates. Further, the DNMT1KO and ADAR inhibition attenuate HFD-induced NGAL/FGF23/TMPRSS2/MMP2, 9, 13, and uric acid levels and improve cardiac and renal remodeling. Although the novel role of nerve endings by the Piezo channels (i.e., the combination of ENaC, VDAC, TRPV, K+, and Mg2+ channels) in the interoception is suggested, interestingly, we and others have shown mechanisms independent of the nerve, by interoception, such as the cargo of the exosome in denervation models of heart failure. If proper and appropriate levels of these enzymes are available to covert homocysteine to hydrogen sulfide (H2S) during homocystinuria, then the H2S can potentially serve as a newer form of treatment for morning heart attacks and renal sulfur transsulfuration transport diseases.

Sleep health among US Navy afloat versus ashore personnel in the Millennium Cohort Study

Despite emerging public concern regarding the sleep health of military personnel over the past two decades, there remains a dearth of research examining sleep health among naval personnel assigned to sea duty. This study examined sleep metrics (e.g. fatigue, short sleep duration) and mental (e.g. posttraumatic stress disorder, depression) and physical health (e.g. type 2 diabetes, bodily pain) outcomes among naval personnel with recent sea duty (i.e. afloat) compared with naval personnel with recent shore duty (i.e. ashore). Prevalence ratios and mean differences for all outcomes were estimated and adjusted for demographic and military variables, and subsequently stratified by obesity. Sleep metrics were similar between afloat and ashore sailors except for short sleep duration, while sailors with recent shore duty had poorer physical health compared with those with recent sea duty. Stratified analyses suggested naval personnel with obesity had a higher proportion of nearly all adverse sleep-related health outcomes than those without obesity. Among participants without obesity, afloat personnel were more likely to report very short sleep (≤ 5 hours) and fewer hours of average nightly sleep, but were less likely to report physical health outcomes compared with ashore personnel. These findings suggest potential differences in sleep metrics and sleep-related health outcomes between afloat and ashore naval personnel. Additional research examining sleep outcomes using more objective measures is required to further investigate these findings, which may inform strategies to foster consolidated sleep despite environmental and occupational challenges in order to maintain high-performing naval personnel.

A qualitative investigation of demands, resources and self-regulation during Navy deployment

Creating a sustainable workplace for Navy personnel is vital for their wellbeing and retention. This qualitative study explores the interplay between job and personal demands, resources, and stress self-regulation strategies affecting psychological strain among Navy personnel during deployment. We conducted semi-structured key informant interviews with 25 Navy personnel (68% male) to determine the demands and resources at sea that affect psychological strain. The findings identified that individual differences in coping strategies (e.g., recovery management), abilities (i.e. ability to make social connections), and their mind-set about deployment (e.g., sense of purpose) were perceived to play a role in the experience of strain. Additionally, the presence of supportive peers and leaders was identified as a key resource, whereas external stressors (e.g., family crisis) and social tension onboard, amplified by confined spaces, were commonly reported demands. Our findings also contribute to a growing body of research suggesting a nuanced interaction between individual coping strategies and job design. Formal organizational support was identified as enabling adaptive self-regulation strategies, while the capacity to form and maintain positive relationships helped foster a sense of belonging, countering isolation. Another key contribution was the individual differences in the appraisal of resources offered by the organization and the potential importance of resource appraisal in how effective resources were perceived to be for addressing shipboard demands. We provide recommendations relating to targets for personnel training, interventions, and leadership in terms of communication, supporting day-to-day and equal opportunity for recovery, resource access, maintaining morale, and shaping the evaluation of demands.

Positive impact of sunlight exposure on mental health in a naval population

Naval shipboard operations impose numerous environmental and occupational stressors, which can adversely affect mental and physical health outcomes. Moreover, this operational setting also complicates the implementation of countermeasures to protect personnel from these stressors. Thus, any easily accessible or modifiable protective factors should be explored further for their potential to support the health of military personnel. Daily sunlight exposure is one such factor that has demonstrated positive effects on health outcomes. For the current study, sunlight exposure and self-reported health outcomes were explored in a large population of U.S. Navy personnel (N > 11,000). Mediator analyses examined the relationship between mental and physical health while controlling for key confounding variables such as morale and exercise. Although the overall regression models indicated only a slight impact on physical health, sunlight exposure had a significant direct effect on mental health even while controlling for the mediating influence of morale. Sunlight exposure also had an impact on morale and an indirect influence on mental health through morale. Additional analyses further supported the possible mental health benefits of sunlight exposure even while accounting for occupational differences. The results suggest that prescribed sunlight exposure aboard ships could be used to promote positive mental health during naval operations.

From trenches to technology: a narrative review of sleep medicine in the military

Diagnoses of military-relevant sleep disorders have increased substantially since the terrorist attacks of September 11, 2001. The cause of this increase appears to be complicated and multifactorial, with military and civilian populations clearly differing with respect to both the nature and distribution of sleep disorders diagnoses. In part, these differences may be attributable to the fact that a majority of service members are chronically sleep-restricted-an unavoidable consequence of continuous and sustained military operations that "set the stage" for development of specific sleep disorders. The purpose of this narrative review is to describe the military relevance of several common sleep disorders, assess the extent to which these disorders currently constitute a burden on the military health care system, and suggest strategies to alleviate that burden. The military health care system does not have enough sleep medicine providers to address the immediate and long-term consequences of sleep disorders in military personnel. Digital technologies and education packages can be leveraged to improve access to care.

CITATION

Thomas CL, Carr K, Yang F, et al. From trenches to technology: a narrative review of sleep medicine in the military. J Clin Sleep Med. 2024;20(6):973-981.

Steps toward developing a comprehensive fatigue monitoring and mitigation solution: perspectives from a cohort of United States Naval Surface Force officers

Study Objectives

This study analyzed fatigue and its management in US Naval Surface Force warships, focusing on understanding current practices and barriers, and examining the influence of organizational and individual factors on managing chronic fatigue. Furthermore, this study explored the impact of organizational and individual factors on fatigue management.

Methods

As part of a larger study, 154 naval officers (mean ± standard deviation; 31.5 ± 7.0 years; 8.8 ± 6.8 years of service; 125 male, and 29 female) completed a fatigue survey. The survey addressed (1) self-reported fatigue, (2) fatigue observed in others, (3) fatigue monitoring strategies, (4) fatigue mitigation strategies, and (5) barriers to fatigue mitigation. Logistic and ordinal regressions were performed to examine the effect of individual (i.e. sleep quality and years in military service) and organizational (i.e. ship-class) factors on fatigue outcomes.

Results

Fatigue was frequently experienced and observed by 23% and 54% of officers, respectively. Of note, officers often monitored fatigue reactively (i.e. 65% observed others nodding off and 55% observed behavioral impairments). Still, officers did not frequently implement fatigue mitigation strategies, citing few operationally feasible mitigation strategies (62.3%), being too busy (61.7%), and not having clear thresholds for action (48.7%). Fatigue management varies across organizational factors, which must be considered when further developing fatigue management strategies.

Conclusions

Fatigue remains a critical concern aboard surface force ships and it may be better addressed through development of objective sleep and fatigue monitoring tools that could inform leadership decision-making.