Sleep and Military Leaders: Examining the Values, Beliefs, and Quality of Sleep and the Impact on Occupational Performance

INTRODUCTION

Sleep deprivation is rampant within the military population, and insufficient sleep can lead to physical and mental health problems impacting soldier's readiness and deployability. Past research has shown the importance of leadership's role in subordinates' sleep health. Understanding the values, beliefs, and quality of military leader sleep is essential to the development of effective interventions to optimize occupational performance and overall sleep health. Therefore, the purpose of this study was to examine the military leaders' values, beliefs, and sleep quality and the impact on occupational performance. The authors aimed to (1) identify military leaders' sleep quality and beliefs; (2) explore the relationship between military leaders' sleep quality, beliefs and attitudes about sleep, and impact on occupational performance; and (3) examine the value leaders place on sleep for themselves and subordinates in relation to occupational performance.

MATERIALS AND METHODS

This observational, mixed-methods study design recruited a convenience sample of 109 Army active duty medical service members currently serving in a leadership role. Participants completed an electronic survey to include general demographic information and three self-report measures: the Pittsburgh Quality of Sleep Index, the Dysfunctional Beliefs about Sleep, and the Functional Outcomes of Sleep Questionnaire. Eleven participants completed the semi-structured qualitative interview focusing on sleep values and the impacts on performance. Univariate and multivariate regressions were performed for statistical analysis of the quantitative survey data, whereas thematic analysis was used to analyze the qualitative interview data. This study was approved by the U.S. Army Medical Center of Excellence Institutional Review Board.

RESULTS

Multivariate regression analysis demonstrated small-to-medium effect sizes (R2 = 0.355-0.559) for relationships between sleep quality, sleep beliefs, functional performance, and demographic variables. More specifically, military grade, position, use of alcohol, time in service, and gender were all found to contribute significantly to scores on the Pittsburgh Sleep Quality Index, the Dysfunctional Beliefs About Sleep Scale-16, and the Functional Outcomes of Sleep Questionnaire-10 (P < .05). Qualitative data resulted in three primary themes: (1) Poor sleep degrades performance, (2) sleep is a top priority, and (3) leaders have a responsibility for subordinates' sleep health.

CONCLUSIONS

This sample of military leaders was found to perceive themselves as poor-quality sleepers despite demonstrating more functional attitudes and beliefs about sleep and reporting normal-to-mild impairments in daily functioning as a result of daytime sleepiness. Furthermore, findings suggest that leaders' sleep quality and beliefs stand to be further improved, whereas their sleep values need to be consistently demonstrated to subordinates. With a clearer understanding of military leaders' values, beliefs, and sleep quality, future research could focus on implementing and developing holistically based and individualized sleep interventions intended to optimize performance and sleep health.

A social-ecological examination of sleep among Airmen in technical training

Inadequate sleep is an on-going risk to the health and mission readiness of U.S. Armed Forces, with estimates of sleep problems high above U.S. civilian populations. Intervening early in the career of active duty Air Force personnel (or "Airmen") with education and the establishment of healthy behaviors may prevent short and long term-detriments of sleep problems. This paper describes the results of a qualitative study seeking to understand the facilitators and barriers to achieving good sleep in a technical training school during the first year of entry into the United States Air Force. Using the social ecological framework and content analysis, three focus groups with Airmen were conducted to explore themes at the individual, social, environmental, and organizational/policy level. Overall, results indicated a cohort motivated to achieve good sleep, and also struggling with a number of barriers across each level. This paper highlights opportunities for population health interventions during technical training aimed at supporting Airmen in developing healthy sleep behaviors early in the course of their career.

Sleep duration and perceptions of sleep quality in British Army recruits during basic training - an observational analysis

Introduction

Sleep is critical to the health, wellbeing and performance of military personnel during basic training. This two-part study evaluated sleep-wake patterns and sleep disturbances in junior soldiers (JS) and infantry recruits in Autumn 2021 (study 1), and non-infantry recruits in spring 2022 (study 2).

Methods

During studies 1 and 2, validated wearable technology combined with a sleep diary was used to quantify sleep-wake indices, sleep disturbances and perceptions of sleep quality. Sleep diary data was analysed descriptively. A series of repeated-measures ANOVAs examined differences in objective sleep-wake indices. Correlation analysis determined associations between time in bed (TIB) and total sleep time (TST).

Results

Significant (p < 0.05) differences in most sleep-wake indices were observed between weeks of basic training for all cohorts. Strong positive correlations between TIB and TST were observed for each cohort across basic training (r = 0.681 - 0.970, p < 0.001), with longer TST associated with greater TIB. The mean±SD sleep duration (hours and mins [hm]) for JS (06:22 ± 00:27hm), non-infantry (05:41 ± 00:47hm) and infantry (05:46 ± 00:34hm) recruits across basic training was consistently below national recommendations. The mean±SD bed and wake times for JS (bedtime: 23:01 ± 00:32hm; awake: 05:34 ± 00:10hm), non-infantry (bedtime: 23:38 ± 01:09hm; awake: 04:47 ± 00:58hm), and infantry (bedtime: 23:13 ± 00:29hm; awake: 05:38 ± 00:26hm) recruits varied across weeks of basic training, with over 80% reporting "fairly bad" or "very bad" sleep quality and frequent periods of "dozing off" during daytime activity. The most commonly reported sleep disturbing factors identified during basic training involved: late-night military admin (e.g., ironing, boot cleaning, kit set up etc), early morning wake times, extraneous noise, light and hot room temperatures within the primary sleeping environment, bed/mattress discomfort, muscle soreness and feelings of stress and anxiety.

Discussion/Conclusion

Our findings contribute to the existing evidence that long-term sleep loss is pervasive during initial military training programmes. The average sleep durations indicate chronic and unrecoverable sleep loss which would be expected to significantly impair physical and cognitive military performance, and increase the risk of injury, illness and attrition rates during basic training. Changes in the design and scheduling of basic training programmes to enable, at the least, minimum sleep recommendations to be met, and to improve sleep hygiene in the primary sleeping environment are warranted.

Delaying early morning workouts to protect sleep in two-a-day athletes

Two-a-day training is common for endurance athletes with training sessions typically beginning at 6 a.m. and 3 p.m. or 4 p.m. However, the early morning workouts could contribute to significant sleep loss, especially for night owls. Chronic sleep loss over a season could result in impaired performance, as well as an increased risk of physical and mental illness. It is hypothesized that shifting the early morning workout to later in the day could have beneficial effects for these athletes. A number of obstacles could make this hypothesis difficulty to test and implement. However, such a change could have dramatic benefits for some athletes.

Subjective Measures of Workload and Sleep in Australian Army Recruits; Potential Utility as Monitoring Tools

INTRODUCTION

Subjective measures may offer practitioners a relatively simple method to monitor recruit responses to basic military training (BMT). Yet, a lack of agreement between subjective and objective measures may presents a problem to practitioners wishing to implement subjective monitoring strategies. This study therefore aims to examine associations between subjective and objective measures of workload and sleep in Australian Army recruits.

MATERIALS AND METHODS

Thirty recruits provided daily rating of perceived exertion (RPE) and differential RPE (d-RPE) for breathlessness and leg muscle exertion each evening. Daily internal workloads determined via heart rate monitors were expressed as Edwards training impulse (TRIMP) and average heart rate. External workloads were determined via global positioning system (PlayerLoadTM) and activity monitors (step count). Subjective sleep quality and duration was monitored in 29 different recruits via a customized questionnaire. Activity monitors assessed objective sleep measures. Linear mixed-models assessed associations between objective and subjective measures. Akaike Information Criterion assessed if the inclusion of d-RPE measures resulted in a more parsimonious model. Mean bias, typical error of the estimate (TEE) and within-subject repeated measures correlations examined agreement between subjective and objective sleep duration.

RESULTS

Conditional R2 for associations between objective and subjective workloads ranged from 0.18 to 0.78, P < 0.01, with strong associations between subjective measures of workload and TRIMP (0.65-0.78), average heart rate (0.57-0.73), and PlayerLoadTM (0.54-0.68). Including d-RPE lowered Akaike Information Criterion. The slope estimate between objective and subjective measures of sleep quality was not significant. A trivial relationship (r = 0.12; CI -0.03, 0.27) was observed between objective and subjective sleep duration with subjective measures overestimating (mean bias 25 min) sleep duration (TEE 41 min).

CONCLUSIONS

Daily RPE offers a proxy measure of internal workload in Australian Army recruits; however, the current subjective sleep questionnaire should not be considered a proxy measure of objective sleep measures.

Quantification of Recruit Training Demands and Subjective Wellbeing during Basic Military Training

Purpose: Assess and describe the physical demands and changes in subjective wellbeing of recruits completing the 12 week Australian Army Basic Military Training (BMT) course. Methods: Thirty-five recruits (24.8 ± 6.8 y; 177.4 ± 10.1 cm, 75.6 ± 14.7 kg) consented to daily activity monitoring and weekly measures of subjective wellbeing (Multi-component Training Distress Scale, MTDS). The physical demands of training were assessed via wrist worn activity monitors (Actigraph GT9X accelerometer). Physical fitness changes were assessed by push-ups, sit-ups and multi-stage shuttle run in weeks 2 and 8. Results: All objective and subjective measures significantly changed (p < 0.05) across the 12 week BMT course. In parallel, there was a significant improvement in measures of physical fitness from weeks 2 to 8 (p < 0.001). The greatest disturbance to subjective wellbeing occurred during week 10, which was a period of field training. Weeks 6 and 12 provided opportunities for recovery as reflected by improved wellbeing. Conclusions: The physical demands of training varied across the Australian Army 12 week BMT course and reflected the intended periodization of workload and recovery. Physical fitness improved from week 2 to 8, indicating a positive training response to BMT. Consistent with findings in sport, wellbeing measures were sensitive to fluctuations in training stress and appear to have utility for individual management of personnel in the military training environment.

Perception of the Special Troops (Commando) Soldiers Regarding Physical Fitness, Motor Control and Psychological Skills

Physical fitness and motor skills are considered important attributes for the military, affecting their professional performance. The high physical and psychological demand that the special forces are subjected to requires the acquisition of a set of volitional skills such as resilience, effort, perseverance, or resistance to frustration, which are worthy of further research. This study aimed to analyse the perception of the special troops (commandos) in physical fitness, motor control and psychological skills. A total of 35 male soldiers that ended the commando recruit training program (21.69 ± 2.36 years old) were investigated. A questionnaire was applied to verify differences in perception of physical fitness, motor capacity, physical effort and military training during recruit training according to age, education, work experience and sports background. Descriptive statistics were used to characterize the participants. All data collected were analysed using IBM-SPSS Statistics, version 24. Our results revealed differences in the importance given to the training of motor skills within military training (χ2 = 19.284; p = 0.023), conditional motor skills – speed (χ2 = 17.378; p = 0.043), coordinative motor skills—motor control (χ2 = 20.616; p = 0.014), psychological skills in a military context (χ2 = 13.730; p = 0.008), volitional skills—resistance to frustration (χ2 = 21.568; p = 0.043) and volitional skills—psychological resistance (χ2 = 29.144; p = 0.004). The participants highlighted the importance of instructors having scientific knowledge in physical education to provide military physical training to be better prepared for this purpose. We concluded that motor skills and psychological abilities tend to be equally important in the context of military training. Physical fitness and motor skill development can be considered essential in military training for most of the inquired participants.

The Development, Implementation, and Feasibility of a Circadian, Light, and Sleep Skills Program for Shipboard Military Personnel (CLASS-SM)

Service members face unique barriers to sufficient and high quality sleep. In the present study, a circadian, light, and sleep skills program for shipboard military personnel (CLASS-SM) was designed to encourage and inform strategies that support optimal sleep and circadian health in the context of those barriers. Phase 1 included program development and refinement via an iterative formative evaluation, including structured interviews with service members and feedback from veterans and experts, resulting in further tailoring to the population. In Phase 2, the highly tailored program was administered to shipboard personnel (n = 55), and acceptability indicators were measured. Sleep- and circadian-related knowledge (pre- and post-program) and the perceived relevance of, and satisfaction with, program content (post-program) were assessed. Before the intervention, most individuals were unaware that 7−9 h of sleep is recommended (72%) and had little understanding of the physiological effects of light; however, knowledge scores increased significantly post-program, from 51% to 88% correct (p < 0.0001). Reception was positive, with high reported satisfaction and relevance. Most individuals reported that they learned something new (89%), planned to use one or more learned strategies (100%), and intended to share learned information with others (85%); the physiological effects of light and circadian rhythms were the content areas most frequently reported as new and useful. The results demonstrate the need for, and feasibility of, the delivery of this program in operational environments.

Sleep of recruits throughout basic military training and its relationships with stress, recovery, and fatigue

Objective

Studies in basic military training (BMT) examining sleep are largely cross-sectional, and do not investigate relationships between sleep, stress, recovery and fatigue. The aims of this study were to (1a) quantify changes in recruits’ sleep quantity and quality over 12 weeks of BMT; (1b) quantify changes in recruits’ perceptions of stress, fatigue and recovery over BMT; and (2) explore relationships between sleep, and perceptions of stress, fatigue and recovery.

Methods

45 recruits (37 male; 8 female, age: 25.2 ± 7.2 years, height: 176.2 ± 10.0 cm, mass: 76.8 ± 15.0 kg) wore ActiGraph GT9X’s for 12 weeks of BMT, collecting sleep duration, efficiency and awakenings. Subjective sleep quality, fatigue were measured daily, with stress and recovery measured weekly. Multi-level models assessed relationships between sleep, and stress, recovery, and fatigue.

Results

Objective daily means for sleep duration were 6.3 h (± 1.2 h) and 85.6% (± 5.5%) for sleep efficiency. Main effects were detected for all mean weekly values (p < 0.05). Sleep quality showed the strongest relationships with stress, recovery and fatigue. The best model to explain relationships between, stress, recovery and fatigue, included sleep quality, sleep duration, sleep efficiency and awakenings.

Conclusions

The reported mean sleep duration of 6.3 h per night may negatively impact training outcomes across BMT. Combining both subjective and objective measures of sleep best explained relationships between sleep metrics stress, fatigue and recovery. Perceived sleep quality was most strongly related to change in stress, recovery, or post-sleep fatigue.

How sleep can help maximize human potential: The role of leaders

OBJECTIVE

During multi-domain operations (MDO), soldiers need the physical supremacy, cognitive dominance, and emotional resilience to help defend and win our nation's wars. Optimal sleep has been shown to boost physical performance and cognitive processing. This manuscript will discuss how recent advances in sleep science strongly argue for the integration of sleep planning into military operations.

DESIGN

Review article.

METHODS

We reviewed the current understanding of how sleep affects Soldier readiness, how sleep and pain are interrelated, and unique challenges to obtaining adequate sleep in military training environments. We then address solutions that can be implemented by leaders and individuals to manage warfighter fatigue and optimize unit performance.

RESULTS

Since sleep is foundational to soldier health and readiness, improving warfighter fatigue management is a priority for leaders.

CONCLUSION

To succeed in MDO, military personnel require physical supremacy, cognitive dominance, and emotional resilience to fight and win. Sleep science is a rapidly emerging field, and the clear implications for maximizing human performance argue strongly for more deliberate integration into military training and operations. Leaders that incorporate sleep and fatigue management into the planning and execution phases of operations will help facilitate mission priorities and prove a powerful force multiplier.

Engaging Stakeholders to Optimize Sleep Disorders' Management in the U.S. Military: A Qualitative Analysis

INTRODUCTION

Sleep disorders' are highly prevalent among U.S. active duty service members (ADSMs) and present well-documented challenges to military health, safety, and performance. In addition to increased need for sleep medicine services, a major barrier to effective sleep management has been a lack of alignment among patients, health providers, and economic-decision-makers. To address this gap in knowledge, the purpose of the present study was to engage diverse stakeholders vested in improving sleep disorders' management in the military.

MATERIALS AND METHODS

We elicited feedback from ADSMs with sleep disorders (five focus group discussion, n = 26) and primary care managers (PCMs) (11 individual semi-structured interview) in two military treatment facilities (MTFs) in the National Capitol Region, in addition to national level military and civilian administrative stakeholders (11 individual semi-structured interview) about their experiences with sleep disorders' management in U.S. MTFs, including facilitators and barriers for reaching a definitive sleep diagnosis, convenience and effectiveness of sleep treatments, and key desired outcomes from interventions designed to address effectively sleep disorders in the U.S. military health care system (MHS). Recordings from focus groups and semi-structured interviews were transcribed verbatim and analyzed using QSR International's NVivo 12 software using inductive thematic analysis. The study was approved by Walter Reed National Military Medical Center Department of Research Programs.

RESULTS

Active duty service members with sleep disorders often fail to recognize their need for professional sleep management. Whereas PCMs identified themselves as first-line providers for sleep disorders in the military, patients lacked confidence that PCMs can make accurate diagnoses and deliver effective sleep treatments. Active duty service members cited needs for expeditious treatment, educational support and care coordination, and support for obtaining sleep treatments during deployment. Challenges that PCMs identified for effective management include insufficient time during routine care visits, delays in scheduling testing procedures, and limited number of sleep specialists. Primary care managers suggested offering evidence-based telehealth tools and enhanced care coordination between PCMs and specialists; standardized medical education, materials, and tools; patient preparation before appointments; self-administered patient education; and including behavioral sleep specialists as part of the sleep management team. For administrative stakeholders, key outcomes of enhanced sleep management included (1) improved resource allocation and cost savings, and (2) improved ADSM safety, productivity, and combat effectiveness.

CONCLUSION

Current military sleep management practices are neither satisfactory nor maximally effective. Our findings suggest that solving the military sleep problem will require sustained effort and ongoing collaboration from ADSM patients, providers, and health systems leaders. Important potential roles for telehealth and technology were identified. Future research should seek to enhance implementation of sleep management best practices to improve outcomes for patients, providers, MHS, and the military as a whole.

Longitudinal associations of military-related factors on self-reported sleep among U.S. service members

STUDY OBJECTIVES

Sleep loss is common in the military, which can negatively affect health and readiness; however, it is largely unknown how sleep varies over a military career. This study sought to examine the relationships between military-related factors and the new onset and reoccurrence of short sleep duration and insomnia symptoms.

METHODS

Millennium Cohort Study data were used to track U.S. military service members over time to examine longitudinal changes in sleep. Outcomes were self-reported average sleep duration (categorized as ≤5 hours, 6 hours, or 7-9 hours [recommended]) and/or insomnia symptoms (having trouble falling or staying asleep). Associations between military-related factors and the new onset and reoccurrence of these sleep characteristics were determined, after controlling for multiple health and behavioral factors.

RESULTS

Military-related factors consistently associated with an increased risk for new onset and/or reoccurrence of short sleep duration and insomnia symptoms included active duty component, Army or Marine Corps service, combat deployment, and longer than average deployment lengths. Military officers and noncombat deployers had decreased risk for either sleep characteristic. Time-in-service and separation from the military were complex factors; they lowered risk for ≤5 hours sleep but increased risk for insomnia symptoms.

CONCLUSIONS

Various military-related factors contribute to risk of short sleep duration and/or insomnia symptoms over time, although some factors affect these sleep characteristics differently. Also, even when these sleep characteristics remit, some military personnel have an increased risk of reoccurrence. Efforts to improve sleep prioritization and implement interventions targeting at-risk military populations, behaviors, and other significant factors are warranted.

The Military Service Sleep Assessment: an instrument to assess factors precipitating sleep disturbances in U.S. military personnel

STUDY OBJECTIVES

Military personnel frequently experience sleep difficulties, but little is known regarding which military or life events most impact their sleep. The Military Service Sleep Assessment (MSSA) was developed to assess the impact of initial military training, first duty assignment, permanent change of station, deployments, redeployments, and stressful life events on sleep. This study presents an initial psychometric evaluation of the MSSA and descriptive data in a cohort of service members.

METHODS

The MSSA was administered to 194 service members in a military sleep disorders clinic as part of a larger study.

RESULTS

Average sleep quality on the MSSA was 2.14 (on a Likert scale, with 1 indicating low and 5 indicating high sleep quality), and 72.7% (n = 140) of participants rated their sleep quality as low to low average. The events most reported to negatively impact sleep were stressful life events (41.8%), followed by deployments (40.6%). Military leadership position (24.7%) and birth/adoption of a child (9.7%) were the most frequently reported stressful life events to negatively impact sleep. There were no significant differences in current sleep quality among service members with a history of deployment compared with service members who had not deployed.

CONCLUSIONS

The MSSA is the first military-specific sleep questionnaire. This instrument provides insights into the events during a service member's career, beyond deployments, which precipitate and perpetuate sleep disturbances and likely chronic sleep disorders. Further evaluation of the MSSA in nontreatment-seeking military populations and veterans is required.

Sleep health of incoming army trainees and how it changes during basic combat training

OBJECTIVE

To examine the sleep health of incoming Army trainees and how it is impacted during basic combat training (BCT).

DESIGN

Prospective.

SETTING

BCT site (Fort Jackson, SC).

PARTICIPANTS

A total of 1349 trainees (936 = male, 413 = female, 20.73 ± 3.67 years).

MEASUREMENTS

Participants completed the Pittsburgh Sleep Quality Index (PSQI), the Morningness/Eveningness Questionnaire, and the Epworth Sleepiness Scale at the start of BCT and a modified PSQI at the end of BCT.

RESULTS

At baseline, trainees reported an average sleep duration of 7.65 ± 1.68 hours per night, with 81.8% rating their sleep quality as "Very Good or Fairly Good." The mean reported Morningness/Eveningness Questionnaire score was 50.63 ± 8.11 and the mean Epworth Sleepiness Scale was 8.60 ± 4.02. Reported sleep duration was significantly less during BCT (6.73 ± 0.90 hours) compared to baseline (P< .001). There was no significant difference in the mean PSQI Global score at the end of BCT compared to the start (5.33 ± 3.00 vs. 5.42 ± 2.85, P = .440), however, 6 of the 7 component scores were significantly different (with Sleep Quality, Sleep Duration, and Daytime Dysfunction scores being higher/worse and Sleep Latency, Sleep Efficiency, and Sleep Medication Use scores being lower/improved [all P < .01]).

CONCLUSIONS

Army BCT trainees in this large sample reported good sleep health characteristics at entry to training, including achieving recommended sleep amounts (>7 hours per night) and reporting good sleep quality. During BCT, negative changes were observed in reported sleep duration and quality in trainees. Further investigation into the factors contributing to changes in trainees' sleep health during BCT and the implications on subsequent readiness, injury risk, and performance is warranted.

Sleep problems and functioning during initial training for a high-risk occupation

OBJECTIVES

The current study sought to characterize the sleep problems of soldiers entering Basic Combat Training and to identify the link between sleep problems and subsequent performance, psychological distress, anger reactions, and attention.

DESIGN

Soldiers were surveyed at 4 time points throughout the standard 10 weeks of Basic Combat Training. Surveys were administered at weeks 1, 3, 6, and 9. Sleep problems were identified as either present or absent at each time point using a sleep problem screening questionnaire. Four sleep patterns were identified and then used to evaluate outcomes throughout training (n = 1577).

RESULTS

When compared to those who never had a sleep problem ("healthy "; 60.6%), those who recovered from their initial sleep problem ("recovered"; 12.8%) started training with higher psychological distress and anger reactions and lower attention but steadily improved throughout training. Those who developed a sleep problem during training ("new onset"; 20.0%) and those who had a sleep problem throughout training ("chronic"; 6.6%) also started off significantly worse than the healthy group. The new-onset and chronic groups saw slower psychological distress improvement and a decline in attention throughout the course compared to the healthy group. The chronic group also significantly increased their anger reactions throughout training compared to the healthy group.

CONCLUSION

Sleep problems during Basic Combat Training may be an indicator for difficulties managing entry into the military. These findings highlight the importance of improving sleep health for soldiers throughout Basic Combat Training and for others with similar training in high-risk occupations.

Increased Risk of Upper Respiratory Infection in Military Recruits Who Report Sleeping Less Than 6 h per night

Introduction

Professional sleep associations recommend 7-9 h of sleep per night for young adults. Habitually sleeping less than 6 h per night has been shown to increase susceptibility to common cold in otherwise healthy, adult civilians. However, no investigations have examined the importance of sleep duration on upper respiratory tract infection (URTI) and loss of training days in military recruits. The purpose of this study was to describe self-reported sleep duration in a large cohort of military recruits and to assess the relationship between reported sleep duration and incidence of URTI's. We hypothesized that recruits who reported sleeping less than the recommended 7-9 h per night during training suffered a greater incidence of URTI and, as a consequence, lost more training days compared with recruits who met sleep recommendations.

Materials and Methods

Participants included 651 British Army recruits aged 22 ± 3 yr who completed 13 wk of basic military training (67% males, 33% females). Participants were members of 21 platoons (11 male, 10 female) who commenced training across four seasons (19% winter, 20% spring, 29% summer, and 32% autumn). At the start and completion of training, participants completed a questionnaire asking the typical time they went to sleep and awoke. Incidence of physician-diagnosed URTI and lost training days due to URTI were retrieved from medical records.

Results

Self-reported sleep duration decreased from before to during training (8.5 ± 1.6 vs. 7.0 ± 0.8 h; p < 0.01). Prior to training, 13% of participants reported sleeping less than the recommended 7 h sleep per night; however, this increased to 38% during training (X2 = 3.8; p = 0.05). Overall, 49 participants (8%) were diagnosed by a physician with at least one URTI and 3 participants (<1%) were diagnosed with two URTI's. After controlling for sex, body mass index, season of recruitment, smoking, and alcohol, participants who reported sleeping less than 6 h per night during training were four times more likely to be diagnosed with URTI compared with participants who slept 7-9 h per night in a logistic regression model (OR 4.4; 95% CI, 1.5-12.9, p < 0.01). On average, each URTI resulted in 2.9 ± 1.5 lost training days. Participants who were diagnosed with URTI had more overall lost training days for any illness compared with participants who did not report a URTI during basic military training (3.3 ± 1.9 vs. 0.4 ± 1.3; p < 0.01).

Conclusion

In a large population of British Army recruits, these findings show that more than one third of participants failed to meet sleep duration recommendations during training. Furthermore, those who reported sleeping less than 6 h per night were four times more likely to be diagnosed with an URTI and lost more training days due to URTI. Since sleep restriction is considered a necessary element of military training, future studies should examine interventions to reduce any negative effects on immunity and host defense.

Sleep Deprivation-Induced Blood-Brain Barrier Breakdown and Brain Dysfunction are Exacerbated by Size-Related Exposure to Ag and Cu Nanoparticles. Neuroprotective Effects of a 5-HT3 Receptor Antagonist Ondansetron

Military personnel are often subjected to sleep deprivation (SD) during combat operations. Since SD is a severe stress and alters neurochemical metabolism in the brain, a possibility exists that acute or long-term SD will influence blood-brain barrier (BBB) function and brain pathology. This hypothesis was examined in young adult rats (age 12 to 14 weeks) using an inverted flowerpot model. Rats were placed over an inverted flowerpot platform (6.5 cm diameter) in a water pool where the water levels are just 3 cm below the surface. In this model, animals can go to sleep for brief periods but cannot achieve deep sleep as they would fall into water and thus experience sleep interruption. These animals showed leakage of Evans blue in the cerebellum, hippocampus, caudate nucleus, parietal, temporal, occipital, cingulate cerebral cortices, and brain stem. The ventricular walls of the lateral and fourth ventricles were also stained blue, indicating disruption of the BBB and the blood-cerebrospinal fluid barrier (BCSFB). Breakdown of the BBB or the BCSFB fluid barrier was progressive in nature from 12 to 48 h but no apparent differences in BBB leakage were seen between 48 and 72 h of SD. Interestingly, rats treated with metal nanoparticles, e.g., Cu or Ag, showed profound exacerbation of BBB disruption by 1.5- to 4-fold, depending on the duration of SD. Measurement of plasma and brain serotonin showed a close correlation between BBB disruption and the amine level. Repeated treatment with the serotonin 5-HT3 receptor antagonist ondansetron (1 mg/kg, s.c.) 4 and 8 h after SD markedly reduced BBB disruption and brain pathology after 12 to 24 h SD but not following 48 or 72 h after SD. However, TiO2-nanowired ondansetron (1 mg/kg, s.c) in an identical manner induced neuroprotection in rats following 48 or 72 h SD. However, plasma and serotonin levels were not affected by ondansetron treatment. Taken together, our observations are the first to show that (i) SD could induce BBB disruption and brain pathology, (ii) nanoparticles exacerbate SD-induced brain damage, and (iii) serotonin 5-HT3 receptor antagonist ondansetron is neuroprotective in SD that is further potentiated byTiO2-nanowired delivery, not reported earlier.

Schlafprobleme bei Soldaten und die Rolle traumatischer Ereignisse bei Auslandseinsätzen

Zusammenfassung. Fragestellung: Schlafprobleme, ihre Auswirkungen und Implikationen sind besonders im Kontext militärischer Missionen ein bedeutsames, jedoch wenig untersuchtes Thema. Methoden: Eine repräsentative Stichprobe von 1478 deutschen Bundeswehrsoldaten wurde 12 Monate nach Ende ihres Auslandseinsatzes mittels des Pittsburgh Sleep Quality Index (PSQI) sowie zu psychischen Störungen (DSM-IV-TR) und traumatischen Ereignissen persönlich untersucht und mit N = 880 Soldaten ohne Auslandseinsatz verglichen. Ergebnisse: 41 % der Soldaten mit und 38 % der Soldaten ohne Auslandseinsatz erfüllten die PSQI-Kriterien für Schlafprobleme. Traumatische Einsatzereignisse waren mit mehr Schlafproblemen assoziiert (β: 0.7, 95 % KI: 0.4 – 1.0, p < .001). In Abhängigkeit der Anzahl traumatischer Einsatzereignisse wurde ein höherer PSQI-Gesamtwert bei inzidenten psychischen Störungen (β: 1.2, 95 % KI: 0.3 – 2.1, p = .011), aber auch bei Soldaten ohne psychische Störungen (β: 0.7, 95 % KI: 0.3 – 1.1, p = .001) berichtet. Schlussfolgerung: Auslandseinsätze scheinen in Abhängigkeit traumatischer Ereignisse das Ausmaß von Schlafproblemen bei Soldaten sowohl innerhalb als auch außerhalb des Kontextes psychischer Störungen zu erhöhen.

The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature

A systematic review was conducted using Samueli Institute’s Rapid Evidence Assessment of the Literature (REAL^©) process to determine the evidence base for melatonin as an agent to optimize sleep or improve sleep quality, and generalize the results to a military, civilian, or other healthy, active, adult population. Multiple databases were searched yielding 35 randomized controlled trials (RCTs) meeting the review’s inclusion criteria, which were assessed for methodological quality as well as for melatonin effectiveness. The majority of included studies were high quality (83.0%). Overall, according to Grading Recommendations, Assessment Development and Evaluation (GRADE) methodology, weak recommendations were made for preventing phase shifts from jet lag, for improving insomnia in both healthy volunteers and individuals with a history of insomnia, and for initiating sleep and/or improving sleep efficacy. Based on the literature to date, no recommendations for use in shift workers or to improve hormonal phase shift changes in healthy people can be made at this time. Larger and longer-duration RCTs utilizing well characterized products are needed to warrant melatonin recommendations in young, healthy adults.

The impact of sleep on soldier performance

The military population is particularly vulnerable to a multitude of sleep-related disorders owing to the type of work performed by active duty servicemembers (ADSMs). Inadequate sleep, due to insufficient quantity or quality, is increasingly recognized as a public health concern. Traditionally, ADSMs have been encouraged that they can adapt to insufficient sleep just as the body adapts to physical training, but there is a substantial body of scientific literature which argues that this is not possible. Additionally, the military work environment creates unique challenges with respect to treatment options for common sleep disorders like obstructive sleep apnea, restless legs syndrome, and parasomnias. This review highlights sleep disorders which are prevalent in the modern military force and discusses the impact of poor sleep on overall performance. Medical treatments and recommendations for unit leaders are also discussed.