Sleep and high-risk behavior in military service members: a mega-analysis of four diverse U.S. Army units

Sleep disturbances and psychological well-being among military medical doctors of the Swiss Armed Forces: study protocol, rationale and development of a cross-sectional and longitudinal interventional study

Background

Compared to civilians and non-medical personnel, military medical doctors are at increased risk for sleep disturbances and impaired psychological well-being. Despite their responsibility and workload, no research has examined sleep disturbances and psychological well-being among the medical doctors (MDs) of the Swiss Armed Forces (SAF). Thus, the aims of the proposed study are (1) to conduct a cross-sectional study (labeled 'Survey-Study 1') of sleep disturbances and psychological well-being among MDs of the SAF; (2) to identify MDs who report sleep disturbances (insomnia severity index >8), along with low psychological well-being such as symptoms of depression, anxiety and stress, but also emotion regulation, concentration, social life, strengths and difficulties, and mental toughness both in the private/professional and military context and (3) to offer those MDs with sleep disturbances an evidence-based and standardized online interventional group program of cognitive behavioral therapy for insomnia (eCBTi) over a time lapse of 6 weeks (labeled 'Intervention-Study 2').

Method

All MDs serving in the SAF (N = 480) will be contacted via the SAF-secured communication system to participate in a cross-sectional survey of sleep disturbances and psychological well-being ('Survey-Study 1'). Those who consent will be provided a link to a secure online survey that assesses sleep disturbances and psychological well-being (depression, anxiety, stress, coping), including current working conditions, job-related quality of life, mental toughness, social context, family/couple functioning, substance use, and physical activity patterns. Baseline data will be screened to identify those MDs who report sleep disturbances (insomnia severity index >8); they will be re-contacted, consented, and randomly assigned either to the eCBTi or the active control condition (ACC) ('Intervention-Study 2'). Individuals in the intervention condition will participate in an online standardized and evidence-based group intervention program of cognitive behavioral therapy for insomnia (eCBTi; once the week for six consecutive weeks; 60-70 min duration/session). Participants in the ACC will participate in an online group counseling (once the week for six consecutive weeks; 60-70 min duration/session), though, the ACC is not intended as a bona fide psychotherapeutic intervention. At the beginning of the intervention (baseline), at week 3, and at week 6 (post-intervention) participants complete a series of self-rating questionnaires as for the Survey-Study 1, though with additional questionnaires covering sleep-related cognitions, experiential avoidance, and dimensions of self-awareness.

Expected outcomes

Survey-Study 1: We expect to describe the prevalence rates of, and the associations between sleep disturbances (insomnia (sleep quality); sleep onset latency (SOL); awakenings after sleep onset (WASO)) and psychological well-being among MDs of the SAF; we further expect to identify specific dimensions of psychological well-being, which might be rather associated or non-associated with sleep disturbances.Intervention-Study 2: We expect several significant condition-by-time-interactions. Such that participants in the eCBTi will report significantly greater improvement in sleep disturbances, symptoms of depression, anxiety, stress reduction both at work and at home (family related stress), and an improvement in the overall quality of life as compared to the ACC over the period of the study.

Conclusion

The study offers the opportunity to understand the prevalence of sleep disturbances, including factors of psychological well-being among MDs of the SAF. Further, based on the results of the Intervention-Study 2, and if supported, eCBTi may be a promising method to address sleep disturbances and psychological well-being among the specific context of MDs in the SAF.

Global prevalence of poor sleep quality in military personnel and veterans: A systematic review and meta-analysis of epidemiological studies

Poor sleep quality is prevalent among members of the military but rates of poor sleep quality vary between studies. This study examined the global prevalence of poor sleep quality in military personnel and veterans as well as possible moderators of prevalence differences between studies. PubMed, EMBASE, Web of Science, and PsycINFO were systematically searched from their inception dates to September 1, 2022. Studies were included if they were conducted on military personnel and/or veterans and prevalence estimates of poor sleep quality could be generated from assessments with standardized tools. A random-effects model was used to calculate the pooled prevalence and its 95% confidence intervals (CIs). Fifty-nine studies (N = 28,100) were included for analysis with sample sizes ranging from 14 to 8481. Two studies were rated as "high quality" (3.39%), while 57 were rated as "moderate quality" (96.61%). The overall pooled prevalence of poor sleep quality in military personnel and veterans was 69.00% (95% CI: 62.33-75.30%); pooled rates were 57.79% (95% CI: 49.88-65.50%) and 82.88% (95% CI: 74.08-90.21%) for active duty personnel and veterans, respectively. Subgroup analyses indicated study region, study design, sampling method, Pittsburg Sleep Quality Index cut-off values, and service type moderated prevalence of poor sleep quality. Meta-regression analyses indicated sample size, mean age, depression and posttraumatic stress disorder (PTSD) were associated with prevalence differences between studies. Poor sleep quality was more common in both active duty military personnel and veterans who were older and those who reported PTSD or depression. Regular monitoring of sleep quality and sleep hygiene should be promoted in this population. More relevant studies in middle- and low-income countries should also be conducted.

Sleep deprivation enhances amyloid beta peptide, p-tau and serotonin in the brain: Neuroprotective effects of nanowired delivery of cerebrolysin with monoclonal antibodies to amyloid beta peptide, p-tau and serotonin

Sleep deprivation is quite frequent in military during combat, intelligence gathering or peacekeeping operations. Even one night of sleep deprivation leads to accumulation of amyloid beta peptide burden that would lead to precipitation of Alzheimer's disease over the years. Thus, efforts are needed to slow down or neutralize accumulation of amyloid beta peptide (AβP) and associated Alzheimer's disease brain pathology including phosphorylated tau (p-tau) within the brain fluid environment. Sleep deprivation also alters serotonin (5-hydroxytryptamine) metabolism in the brain microenvironment and impair upregulation of several neurotrophic factors. Thus, blockade or neutralization of AβP, p-tau and serotonin in sleep deprivation may attenuate brain pathology. In this investigation this hypothesis is examined using nanodelivery of cerebrolysin- a balanced composition of several neurotrophic factors and active peptide fragments together with monoclonal antibodies against AβP, p-tau and serotonin (5-hydroxytryptamine, 5-HT). Our observations suggest that sleep deprivation induced pathophysiology is significantly reduced following nanodelivery of cerebrolysin together with monoclonal antibodies to AβP, p-tau and 5-HT, not reported earlier.

Sleep quality and duration: A key to life satisfaction among military students

Military service is a demanding profession that requires high physical preparedness and mental endurance. At the same time, the demands of military duties often require early rising and shortened sleep duration. Such a reduction in sleep can reduce physical and mental performance, and these changes can be reflected in life satisfaction. For this reason, soldiers' life satisfaction is a crucial variable for their success and long-term service. This study examined the relationship between sleep quality, sleep duration, and life satisfaction in military medical students. The results on 35 military students showed that greater sleep quality corresponded to greater life satisfaction; this relationship was moderate and significant (r = -460, p = .005). Notably, participants (n = 17) who began to wake up without the use of an alarm clock reported an average of 11% higher life satisfaction than the participants who woke to an alarm clock; this difference between participants was statistically significant (p = .011, Cohen's d = .911). Pre- and post-intervention showed that sleep hygiene education could be a suitable solution to prevent sleep deprivation and positively impact life satisfaction. Our findings emphasize the importance of increased sleep hygiene education, especially in preparing future military officers and during military exercises. Prioritizing sleep hygiene in these ways can significantly increase soldiers' life satisfaction.

Physical sleeping environment is related to insomnia risk and measures of readiness in US army special operations soldiers

BACKGROUND

US military service members have characteristically poor sleep, even when 'in garrison' or at one's home base. The physical sleeping environment, which is often poor in military-provided housing or barracks, may contribute to poor sleep quality in soldiers. The current study aimed to assess whether the sleeping environment in garrison is related to sleep quality, insomnia risk and military readiness.

METHODS

Seventy-four US army special operations soldiers participated in a cross-sectional study. Soldiers were queried on their sleeping surface comfort and the frequency of being awakened at night by excess light, abnormal temperatures and noise. Subjective sleep quality and insomnia symptoms were also queried, via the Pittsburgh Sleep Quality Index and Insomnia Severity Index, respectively. Lastly, measures of soldier readiness, including morale, motivation, fatigue, mood and bodily pain, were assessed.

RESULTS

Soldiers reporting temperature-related and light-related awakenings had poorer sleep quality higher fatigue and higher bodily pain than soldiers without those disturbances. Lower ratings of sleeping surface comfort were associated with poorer sleep quality and lower motivation, lower morale, higher fatigue and higher bodily pain. Each 1-point increase in sleeping surface comfort decreased the risk for a positive insomnia screen by 38.3%, and the presence of temperature-related awakenings increased risk for a positive insomnia screen by 78.4%. Those living on base had a poorer sleeping environment than those living off base.

CONCLUSION

Optimising the sleep environment-particularly in on-base, military-provided housing-may improve soldier sleep quality, and readiness metrics. Providers treating insomnia in soldiers should rule out environment-related sleep disturbances prior to beginning more resource-intensive treatment.

Marital status and living apart affect sleep quality in male military personnel: a study of the China's Navy during COVID-19

Background

Marital status is a robust sociodemographic predictor of sleep. Having to live apart from spouse may have different implications than those of cohabitants or singles, especially in military personnel. Further research on this group will help provide knowledge in advance and facilitate early targeted interventions.

Methods

An online questionnaire study was conducted from July to November 2021. A total of 1,832 male military personnel completed the questionnaire. The marital status was measured by a self-reported single choice question. Pittsburgh sleep quality index (PSQI), Epworth Sleepiness Scale (ESS) and The Dysfunctional Beliefs and Attitudes about sleep scale (DBAS-16) were used to measure sleep-related outcomes. Inverse probability weighting (IPW) was applied to reduce the effects of confounding. Logistic regression was used to analyze the relationship between marital status and sleep and explore the impact of living together or not.

Results

After inverse probability weighting, the prevalence of poor sleep quality, sleepiness and dysfunctional beliefs were 16.1, 20.1 and 7.1%, respectively. One-way ANOVA results for the means of both groups were statistically significantly different, except for the sleep latency and sleep disturbance dimensions of PSQI. Participants who were married were more likely to have poor sleep quality (OR: 1.408, 95% CI: [1.10, 1.80]), to have daytime sleepiness (OR: 1.560, 95% CI: [1.27, 1.92]) and to develop dysfunctional beliefs and attitudes (OR: 2.497, 95% CI: [1.65, 3.80]) than those who were unmarried. Further analysis showed that the odds of developing poor sleep quality and DBAS in participants who married but living apart were significantly bigger than those unmarried (OR: 1.548 and 3.991, respectively.), while there were no significant differences in the odds of daytime sleepiness (OR: 0.738, p = 0.050). Age was a protective factor for the development of bad sleep outcomes, while family economic was an independent risk factor.

Conclusion

Marital status appear important for sleep quality, daytime sleepiness and sleep beliefs. The effect of living apart or not should be considered separately as an important predictor of sleep.

Operation early-bird: Investigating altered light exposure in military barracks on sleep and performance-a placebo-controlled study

The manipulation of light exposure in the evening has been shown to modulate sleep, and may be beneficial in a military setting where sleep is reported to be problematic. This study investigated the efficacy of low-temperature lighting on objective sleep measures and physical performance in military trainees. Sixty-four officer-trainees (52 male/12 female, mean ± SD age: 25 ± 5 years) wore wrist-actigraphs for 6 weeks during military training to quantify sleep metrics. Trainee 2.4-km run time and upper-body muscular-endurance were assessed before and after the training course. Participants were randomly assigned to either: low-temperature lighting (LOW, n = 19), standard-temperature lighting with a placebo "sleep-enhancing" device (PLA, n = 17), or standard-temperature lighting (CON, n = 28) groups in their military barracks for the duration of the course. Repeated-measures ANOVAs were run to identify significant differences with post hoc analyses and effect size calculations performed where indicated. No significant interaction effect was observed for the sleep metrics; however, there was a significant effect of time for average sleep duration, and small benefits of LOW when compared with CON (d = 0.41-0.44). A significant interaction was observed for the 2.4-km run, with the improvement in LOW (Δ92.3 s) associated with a large improvement when compared with CON (Δ35.9 s; p = 0.003; d = 0.95 ± 0.60), but not PLA (Δ68.6 s). Similarly, curl-up improvement resulted in a moderate effect in favour of LOW (Δ14 repetitions) compared with CON (Δ6; p = 0.063; d = 0.68 ± 0.72). Chronic exposure to low-temperature lighting was associated with benefits to aerobic fitness across a 6-week training period, with minimal effects on sleep measures.

Nanowired Delivery of Cerebrolysin Together with Antibodies to Amyloid Beta Peptide, Phosphorylated Tau, and Tumor Necrosis Factor Alpha Induces Superior Neuroprotection in Alzheimer's Disease Brain Pathology Exacerbated by Sleep Deprivation

Sleep deprivation induces amyloid beta peptide and phosphorylated tau deposits in the brain and cerebrospinal fluid together with altered serotonin metabolism. Thus, it is likely that sleep deprivation is one of the predisposing factors in precipitating Alzheimer's disease (AD) brain pathology. Our previous studies indicate significant brain pathology following sleep deprivation or AD. Keeping these views in consideration in this review, nanodelivery of monoclonal antibodies to amyloid beta peptide (AβP), phosphorylated tau (p-tau), and tumor necrosis factor alpha (TNF-α) in sleep deprivation-induced AD is discussed based on our own investigations. Our results suggest that nanowired delivery of monoclonal antibodies to AβP with p-tau and TNF-α induces superior neuroprotection in AD caused by sleep deprivation, not reported earlier.

Insomnia and the Interpersonal Theory of suicide among civilians, service members, and veterans

BACKGROUND

Insomnia is associated with suicide risk in civilian and military populations. Thwarted belongingness is proposed as a mediator of this relationship under the Interpersonal Theory of Suicide (IPTS). The present study explored how insomnia relates to suicidal ideation in conjunction with thwarted belongingness among civilians, Service members, and Veterans.

METHODS

Data from the Military Suicide Research Consortium for N = 6556 individuals (6316 with non-missing suicidal ideation status) were divided into 4 subgroups: civilians, never deployed Service members, previously deployed Service members, and Veterans. Robust Poisson models evaluated the associations between insomnia severity/subtype and current suicidal ideation, with bootstrap mediation models assessing thwarted belongingness as a mediator.

RESULTS

A 5-point increase in insomnia severity was associated with a 38% increased risk for current suicidal ideation among civilians, a 56% greater risk among never deployed Service members, an 83% greater risk among previously deployed Service members, and a 37% greater risk among Veterans. Moreover, active Service members showed greater associations between difficulty falling asleep and staying asleep with suicidal ideation than civilians. These associations were independent of covariates and only mediated by thwarted belongingness among Veterans.

CONCLUSIONS

The relationship between insomnia and suicide is not purely explained by thwarted belongingness except among Veterans. Future research should explore additional psychological and neurobiological mechanisms connecting insomnia and suicidality.

Sex moderates the effects of total sleep deprivation and sleep restriction on risk preference

Sleep loss has been shown to alter risk preference during decision-making. However, research in this area has largely focussed on the effects of total sleep deprivation (TSD), while evidence on the effects of sleep restriction (SR) or the potentially moderating role of sex on risk preference remains scarce and unclear. The present study investigated risky decision-making in 47 healthy young adults who were assigned to either of two counterbalanced protocols: well-rested (WR) and TSD, or WR and SR. Participants were assessed on the Lottery Choice Task (LCT), which requires a series of choices between two risky gambles with varying risk levels. Analyses on the pooled dataset indicated across all sleep conditions, participants were generally more risk-seeking when trying to minimise financial loss (LOSSES) than while trying to maximise financial gain (GAINS). On GAINS trials, female participants were more risk-averse during TSD and SR, whereas male participants remained unchanged. On LOSSES trials, female participants remained unchanged during TSD and SR, whereas male participants became more risk-seeking during TSD. Our findings suggest the relationship between sleep loss and risk preference is moderated by sex, whereby changes in risk preference after TSD or SR differ in men and women depending on whether the decision is framed in terms of gains or losses.

Sleep and Infantry Battle Drill Performance in Special Operations Soldiers

BACKGROUND: Although multiple studies have documented the impact of insufficient sleep on soldier performance, most studies have done so using artificial measures of performance (e.g., tablet or simulator tests). The current study sought to test the relationship between sleep and soldier performance during infantry battle drill training, a more naturalistic measure of performance.METHODS: Subjects in the study were 15 junior Special Operations infantry soldiers. Soldiers wore an actigraph and reported their subjective sleep duration and quality prior to close quarter battle (CQB) drills. Experienced leaders monitored each iteration of the CQB exercise and recorded the number of errors committed.RESULTS: The number of errors committed during the live ammunition iterations was negatively correlated with subjective number of hours slept and subjective sleep efficiency/quality during the month prior. Soldiers with subjective sleep duration ≥7 h had a significantly lower number of errors than soldiers with subjective sleep duration <7 h (1.71 vs. 0.63 errors), and soldiers with sleep quality <85% committed more errors than those with sleep quality ≥85% (1.50 vs. 0.40 errors).DISCUSSION: These data preliminarily suggest that sleep quality and duration may influence subsequent performance on infantry battle drill training, particularly for soldiers with limited experience in battle drill conduction who have not yet perfected battle drill techniques. Future studies should enact sleep augmentation to determine the causal influence of sleep on performance in this setting.Mantua J, Shevchik JD, Chaudhury S, Eldringhoff HP, Mickelson CA, McKeon AB. Sleep and infantry battle drill performance in Special Operations soldiers. Aerosp Med Hum Perform. 2022; 93(7):557–561.

The Mind After Midnight: Nocturnal Wakefulness, Behavioral Dysregulation, and Psychopathology

Sufficient sleep with minimal interruption during the circadian/biological night supports daytime cognition and emotional regulation. Conversely, disrupted sleep involving significant nocturnal wakefulness leads to cognitive and behavioral dysregulation. Most studies to-date have examined how fragmented or insufficient sleep affects next-day functioning, but recent work highlights changes in cognition and behavior that occur when someone is awake during the night. This review summarizes the evidence for day-night alterations in maladaptive behaviors, including suicide, violent crime, and substance use, and examines how mood, reward processing, and executive function differ during nocturnal wakefulness. Based on this evidence, we propose the Mind after Midnight hypothesis in which attentional biases, negative affect, altered reward processing, and prefrontal disinhibition interact to promote behavioral dysregulation and psychiatric disorders.

Association of Dietary Behaviors with Poor Sleep Quality and Increased Risk of Obstructive Sleep Apnea in Korean Military Service Members

PURPOSE

Sleep quality among military service members is important for enhancing their capabilities and preventing psychiatric problems. We aimed to explore the association of dietary behaviors with poor sleep quality and increased risk of obstructive sleep apnea (OSA) in military men on active duty.

PATIENTS AND METHODS

A large-scale multi-site cross-sectional survey was conducted in five units of the Republic of Korea's army. Poor sleep quality and increased risk of OSA were defined using the Pittsburgh sleep quality index (PSQI) and Berlin Questionnaire, respectively. Information on dietary behaviors, including the frequency of skipping breakfast, eating snacks, consuming a night meal, and overeating, were collected.

RESULTS

From August 2021 to September 2021, 4389 male respondents, mean age (20.8 ± 1.3 years), completed the survey; 2579 (58.8%) were assessed as having poor sleep quality, and 614 (14.0%) increased risk of OSA. After adjusting for lifestyle and occupational covariates, skipping breakfast 1-2 times weekly was associated with an increased likelihood of experiencing poor sleep quality, compared with not skipping breakfast (odds ratio: 1.23 [95% CI 1.02-1.47]). Eating night meals 5-6 times weekly was also associated with poor sleep quality (odds ratio: 5.54 [95% CI 2.49-14.18]). In addition, skipping breakfast daily (odds ratio: 2.28 [95% CI 1.27-4.03]) and eating night meals daily (odds ratio: 2.30 [95% CI 1.21-4.22]) were related to an increased risk of OSA.

CONCLUSION

Dietary behaviors appear to be related to poor sleep quality and a high risk of OSA. To improve sleep quality, dietary factors could be considered when promoting health programs for military personnel in further research.

Association Between Self-Reported Sleep Quality and Musculoskeletal Injury in Male Army Rangers

INTRODUCTION

Musculoskeletal injuries and insufficient sleep are common among U.S. Army Rangers. There has been limited research into whether indices of sleep differ between injured and uninjured Rangers. The purpose of this study was to investigate the association between self-reported sleep and musculoskeletal injury in Rangers.

MATERIALS AND METHODS

A total of 82 Army Rangers (male, 25.4 ± 4.0 years) were asked if they currently have any musculoskeletal injuries; completed the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), and the Stanford Sleepiness Scale; and were asked about their average sleep quality/sleep duration over the preceding week. Rangers were then dichotomized into groups, one that reported a current musculoskeletal injury and another that did not.

RESULTS

The reported musculoskeletal injury prevalence was 15.9% (n = 13). The Rangers that reported an injury, compared to those that did not, had a significantly higher Global PSQI score (6.7 ± 3.7 versus 4.5 ± 2.7, P = .012) and ISI score (10.9 ± 3.7 versus 7.2 ± 4.1, P = .003), both indicative of poorer sleep. The group reporting an injury rated their average sleep quality over the preceding week significantly lower compared to those that did not report an injury (50.8 ± 17.5 versus 68.9 ± 18.3, P = .001). There was no significant group difference in the average nightly sleep duration (6.1 ± 1.0 hours versus 6.5 ± 0.9 hours, P = .099).

CONCLUSION

In this cohort of male Army Rangers, In this cohort of male Army Rangers, those with a musculoskeletal injury reported poorer sleep quality than uninjured Rangers. Sleep duration was not associated with reported injuries; however, both the injured group and uninjured group averaged less than the recommended amounts of sleep. Further investigation into the relationship between musculoskeletal injury and sleep in military personnel is warranted.

The impact of self-selected short sleep on monetary risk taking

Risky choice has been widely studied in experimental settings, but there is a paucity of research examining the effects of self-selected sleep schedules on risky choices. The current study examined incentivised risky choices of 100 young, healthy adults whose self-selected (at-home) sleep schedules were tracked via actigraphy for 1 week prior to decision making. Average nightly sleep was 6.43 h/night. On each trial of the decision task, individuals chose between two monetary gambles, with separate blocks of trials presenting amounts to gain versus amounts to lose for each paired gamble choice. In general, participants were risk-averse when trying to maximise gains (GAINS) and risk-seeking when trying to minimise losses (LOSSES). These tendencies were amplified in trials where gambles differed more (vs less) in their riskiness. Response times were longer for real choices (vs. dummy trials of random choice), LOSS versus GAINS trials, and when gambles were more similar versus different in risk. Gamble choices were not impacted by actigraphy measured average sleep levels, which suggests self-selected moderate sleep deprivation does not affect risky monetary choices, as has been found in studies of experimentally induced sleep deprivation. However, our data showed that sleep variability increased risk-taking behaviour in the LOSS condition. Thus, risky decision-making may relate more to variability in sleep efficiency than to overall sleep duration or quality in naturalistic settings. The current study gives insight into how decision making in experimental sleep settings may or may not translate to more ecologically valid settings of self-directed sleep.

Sleep and PTSD in the Military Forces: A Reciprocal Relationship and a Psychiatric Approach

Sleep disturbances are well-recognised symptoms of Post-Traumatic Stress Disorder (PTSD). This review updates knowledge regarding the relationship between sleep during deployment, combat-related trauma, and PTSD in military personnel, from which the importance of restorative sleep results. The description of the characteristics of sleep in military forces with the considerable roles of the operational and training contexts highlights the important consequences of degraded sleep. Indeed, a lot of data suggest a dynamic link between sleep and the onset and chronicity of PTSD. We propose a reciprocal relationship model with strategies strongly recommended or already adopted by the military to promote restorative sleep before and after combat exposure. Among the alterations in a variety of sleep architecture and sleep patterns described in PTSD, the physiological hypothesis of REM sleep fragmentation in the development of PTSD symptoms may be important because REM sleep is generally associated with emotional memory. Finally, we address clinical and research perspectives that could be used to detect or restore sleep continuity before and during military deployment to possibly alleviate nightmares and insomnia related to combat exposure and PTSD occurrence and improve our understanding of sleep in PTSD.