How is the COVID-19 pandemic impacting our life, mental health, and well-being? Design and preliminary findings of the pan-Canadian longitudinal COHESION study.

BACKGROUND: With the advent of the COVID-19 pandemic, in-person social interactions and opportunities for accessing resources that sustain health and well-being have drastically reduced. We therefore designed the pan-Canadian prospective COVID-19: HEalth and Social Inequities across Neighbourhoods (COHESION) cohort to provide a deeper understanding of how the COVID-19 pandemic context affects mental health and well-being, key determinants of health, and health inequities. METHODS: This paper presents the design of the two-phase COHESION Study, and descriptive results from the first phase conducted between May 2020 and September 2021. During that period, the COHESION research platform collected monthly data linked to COVID-19 such as infection and vaccination status, perceptions and attitudes regarding pandemic-related measures, and information on participants' physical and mental health, well-being, sleep, loneliness, resilience, substances use, living conditions, social interactions, activities, and mobility. RESULTS: The 1,268 people enrolled in the Phase 1 COHESION Study are for the most part from Ontario (47%) and Quebec (33%), aged 48 ± 16 years [mean ± standard deviation (SD)], and mainly women (78%), White (85%), with a university degree (63%), and living in large urban centers (70%). According to the 298 ± 68 (mean ± SD) prospective questionnaires completed each month on average, the first year of follow-up reveals significant temporal variations in standardized indexes of well-being, loneliness, anxiety, depression, and psychological distress. CONCLUSIONS: The COHESION Study will allow identifying trajectories of mental health and well-being while investigating their determinants and how these may vary by subgroup, over time, and across different provinces in Canada, in varying context including the pandemic recovery period. Our findings will contribute valuable insights to the urban health field and inform future public health interventions.

"Multivariate analysis of the impact of sleep and working hours on medical errors: a MICE approach".

BACKGROUND: The main objective of this study was to describe the relationship between working conditions, sleep and psycho-affective variables and medical errors. METHODS: This was an observational, analytical and cross-sectional study in which 661 medical residents answered questionnaires about working conditions, sleep and psycho-affective variables. Actigraphic sleep parameters and peripheral temperature circadian rhythm were measured in a subgroup of 38 subjects. Bivariate and multivariate predictors of medical errors were assessed. RESULTS: Medical residents reported working 66.2 ± 21.9 weekly hours. The longest continuous shift was of 28.4 ± 10.9 h. They reported sleeping 6.1 ± 1.6 h per day, with a sleep debt of 94 ± 129 min in workdays. A high percentage of them reported symptoms related to psycho-affective disorders. The longest continuous shift duration (OR = 1.03 [95% CI, 1.00-1.05], p = 0.01), working more than six monthly on-call shifts (OR = 1.87 [95% CI, 1.16-3.02], p = 0.01) and sleeping less than six hours per working day (OR = 1.66 [95% CI, 1.10-2.51], p = 0.02) were independently associated with self-reported medical errors. The report of medical errors was associated with an increase in the percentage of diurnal sleep (2.2% [95% CI, 0.1-4.3] vs 14.5% [95% CI, 5.9-23.0]; p = 0.01) in the actigraphic recording. CONCLUSIONS: Medical residents have a high working hour load that affect their sleep opportunities, circadian rhythms and psycho-affective health, which are also related to the report of medical errors. These results highlight the importance of implementing multidimensional strategies to improve medical trainees' sleep and wellbeing, increasing in turn their own and patients' safety.

Actigraphic sleep patterns and cognitive decline in the Hispanic Community Health Study/Study of Latinos.

INTRODUCTION: We determined if actigraphy-derived sleep patterns led to 7-year cognitive decline in middle-aged to older Hispanic/Latino adults. METHODS: We examined 1035 adults, 45 to 64 years of age, from the Hispanic Community Health Study/Study of Latinos. Participants had repeated measures of cognitive function 7 years apart, home sleep apnea studies, and 1 week of actigraphy. Survey linear regression evaluated prospective associations between sleep and cognitive change, adjusting for main covariates. RESULTS: Longer sleep-onset latency was associated with declines in global cognitive function, verbal learning, and verbal memory. Longer sleep-onset latency was also cross-sectionally associated with verbal learning, verbal memory, and word fluency. Sleep fragmentation was not associated with cognitive change. CONCLUSION: In a cohort of mostly middle-aged Hispanic/Latinos, actigraphy-derived sleep-onset latency predicted 7-year cognitive change. These findings may serve as targets for sleep interventions of cognitive decline.

Accessibility and adherence to positive airway pressure treatment in patients with obstructive sleep apnea: a multicenter study in Latin America.

PURPOSE: Information on access and adherence to positive airway pressure (PAP) treatment is lacking at the regional level in Latin America. This study characterized access and adherence to PAP in patients with moderate-severe obstructive sleep apnea (OSA) in Latin America. METHODS: Cross-sectional study, conducted at 9 sleep centers across Argentina, Brazil, Chile, Colombia, Mexico, and Peru. Adults diagnosed with moderate-severe OSA (apnea-hypopnea index [AHI] ≥ 15/h) in the previous 12-18 months were eligible. Anthropometrics, health coverage, and OSA severity data were collected. Data on access to therapy, barriers to access, adherence, and factors related to non-compliance were obtained via standardized telephone survey. RESULTS: Eight hundred eighty patients (70% male, 54 ± 13 years, AHI 49 ± 28/h, body mass index 32 ± 7 kg/m2) were included. Four hundred ninety patients (56%) initiated PAP, 70 (14%) discontinued therapy during the first year (mainly due to intolerance), and 420 (48%) were still using PAP when surveyed. Health insurance was private in 36.9% of patients, via the social security system in 31.1%, and via the state in 13.3%, and 18.7% did not have any coverage; 49.5% of patients had to pay all equipment costs. Reasons for not starting PAP were unclear or absent indication (42%), coverage problems (36%), and lack of awareness of OSA burden (14%). Patients with better adherence were older (55.3 ± 13 vs 52 ± 13; p = 0.002) and had more severe OSA (AHI 51.8 ± 27 vs 45.6 ± 27; p = 0.001). CONCLUSIONS: Less than half moderate-severe OSA patients started and continue to use PAP. Unclear or absent medical indication and financial limitations were the most relevant factors limiting access to therapy.

Negative health outcomes in long sleepers: The societal sleep restriction hypothesis.

Society imposes work and school schedules, as well as social expectations, that militate against consistently obtaining more than 7-9 h of sleep every 24 h. For most but not all adults this sleep duration is adequate. But among those who consistently obtain more than 9 h of sleep per day ("long sleepers"), there likely exists a subpopulation of individuals who are nevertheless failing to obtain enough sleep to satisfy their physiological sleep needs - a consequence of "restricting" their daily sleep durations to whatever extent they can tolerate so as to conform as closely as possible to society's norms and expectations. It is hypothesized that the 'long sleep arm' of the seemingly paradoxical U-shaped relationship between sleep duration and negative health outcomes can be explained, at least in part, by the existence of a subpopulation of such 'sleep-restricted long sleepers.'

Circadian rhythm of autonomic cardiovascular control during Mars500 simulated mission to Mars.

INTRODUCTION: The Mars500 project was conceived to gather knowledge about the psychological and physiological effects of living in an enclosed environment during 520 d as would be required for a real mission to Mars. Our objective was to investigate the circadian profile of heart rate variability (HRV) in the context of the Mars500 study. METHODS: Before, during, and after confinement, 24-h EKG records were obtained from the six crewmembers who participated in the mission. Autonomic activity was evaluated through time and frequency domain indexes of HRV analysis. Circadian rhythmicity was assessed both by averaging hourly HRV along wake and sleep scheduled periods and by fitting a 24-h harmonic to the hourly means. RESULTS: During confinement, wake HRV showed (mean +/- SE) a progressive increase in mean RR interval (from 778 +/- 24 ms to 916 +/- 42 ms), and in the amplitude (values are wavelet power coefficients) of very low (from 13.3 +/- 0.3 to 14.1 +/- 0.2) and high (from 7.8 +/- 0.4 to 8.3 +/- 0.3) frequency components. During sleep, the relative amplitude of the high frequency component of HRV decreased (from 11.8 +/- 1.6 to 9.4 +/- 1.8 normalized units). Overall, sleep-wake differences of HRV showed a progressive decrease of the relative amplitude of the high frequency component. Also, circadian HRV rhythms were dampened during confinement. DISCUSSION: Data revealed diminished amplitude of the rest-activity pattern of the autonomic nervous system parasympathetic function. Reduced daylight exposure and mood changes could account for this observation.

A 2022 Survey of Commercially Available Smartphone Apps for Sleep: Most Enhance Sleep.

Commercially available smartphone apps represent an ever-evolving and fast-growing market. Our review systematically surveyed currently available commercial sleep smartphone apps to provide details to inform both providers and patients alike, in addition to the healthy consumer market. Most current sleep apps offer a free version and are designed to be used while awake, prior to sleep, and focus on the enhancement of sleep, rather than measurement, by targeting sleep latency using auditory stimuli. Sleep apps could be considered a possible strategy for patients and consumers to improve their sleep, although further validation of specific apps is recommended.

National strategy on the integration of sleep and circadian rhythms into public health research and policies: Report from the Canadian Sleep and Circadian Network.

Scientists in sleep and circadian rhythms, public health experts, healthcare providers, partners, and stakeholders convened in 2020 for a 2-day meeting organized by the Canadian Sleep and Circadian Network to develop a national strategy for integrating sleep and circadian rhythms into public health and policies in Canada. The objective of this paper is to present the national strategy that emerged from this meeting of 60 participants from across Canada. The meeting focused on 4 key target priorities: (1) atypical working schedules, (2) sleep and circadian rhythms of children and adolescents, (3) insomnia, and (4) impact of sleep apnea on health. Following constructive discussions, it was decided that the following 4 strategic objectives should be prioritized to accelerate the integration of sleep and circadian rhythms into public health policies in Canada: (1) increase public health sleep and circadian rhythm research, (2) increase public health education and knowledge mobilization on sleep, (3) inform and support public health sleep interventions and policies, and (4) promote sleep health training. Participants recommended that research and public health efforts address needs along the continuum of sleep health. The committee noted that strategies and interventions could differ across contexts, settings, sectors, and jurisdictions. The national strategy also identified high-priority research questions in public health and recommended mechanisms to build research capacity, providing a path forward for the integration of sleep and circadian rhythms into public health research and policies.

Geographically based risk assessment of sleep disorders and disease states impacting medical readiness across active duty army installations from military medical databases in fiscal year 2017.

BACKGROUND: The impact of sleep disorders on active duty Soldiers' medical readiness is clinically significant. Sleep disorders often present high comorbidity with disease states impacting readiness ranging from obesity and drug dependence. Patient data generated from military health databases can be accessed to examine such relationships. The current study performed a risk assessment of sleep disorders, obesity, tobacco use, and substance abuse based on geographical distribution of active duty Army installations through a comprehensive analysis of the Office of the Army Surgeon General Health of the Force report, specifically for Fiscal Year 2017, which summarizes data collected during 2016. METHODS: Health incidences (percent active duty per installation) were queried from the Health of the Force Fiscal Year 2017 (n = 471,000; 85.5% male, >70% between 18 and 34). Nonparametric ranked tests identified active duty Army installations at low risk (green; <25% percentile relative to mean rank), moderate risk (amber; 25%-50% percentile relative to mean rank), and high risk (red; >75% percentile relative to mean rank). Pearson's correlations determined extent of generalized comorbidity of sleep disorders with obesity, tobacco use, and substance abuse across all installations. RESULTS: Large combat arms and training installations of the Southern U.S. were at highest risk for sleep disorder. Mean rank comparisons for sleep disorders versus obesity (P = .306), tobacco use (P = .378), and substance abuse (P = .591) did not differ for each installation. There was a high degree of generalized comorbidity of diagnosed sleep disorder with obesity (P < .001; r2 = 0.963), tobacco use (P < .001; r2 = 0.928), and substance abuse (P < .001; r2 = 0.968). CONCLUSIONS: These risk assessments mirror geographical risk data from civilian populations which is surprising because there is a large degree of inter-individual variability in geographical origin, race/ethnicity, and socioeconomic statuses within a single Army installation. Nevertheless, these data demonstrate strong geographical influences on medical readiness in active duty Soldiers comparable to civilian sectors.

Self-Reported Sleep Need, Subjective Resilience, and Cognitive Performance Following Sleep Loss and Recovery Sleep.

OBJECTIVE: Individuals vary in response to sleep loss: some individuals are "vulnerable" and demonstrate cognitive decrements following insufficient sleep, while others are "resistant" and maintain baseline cognitive capability. Physiological markers (e.g., genetic polymorphisms) have been identified that can predict relative vulnerability. However, a quick, cost-effective, and feasible subjective predictor tool has not been developed. The objective of the present study was to determine whether two factors-"subjective sleep need" and "subjective resilience"-predict cognitive performance following sleep deprivation. METHODS: Twenty-seven healthy, sleep-satiated young adults participated. These individuals were screened for sleep disorders, comorbidities, and erratic sleep schedules. Prior to 40 hours of in-laboratory total sleep deprivation, participants were questioned on their subjective sleep need and completed a validated resilience scale. During and after sleep deprivation, participants completed a 5-minute psychomotor vigilance test every 2 hours. RESULTS: Both subjective resilience and subjective sleep need individually failed to predict performance during sleep loss. However, these two measures interacted to predict performance. Individuals with low resilience and low sleep need had poorer cognitive performance during sleep loss. However, in individuals with medium or high resilience, psychomotor vigilance test performance was not predicted by subjective sleep need. Higher resilience may be protective against sleep loss-related neurobehavioral impairments in the context of subjective sleep need. CONCLUSIONS: Following sleep loss (and recovery sleep), trait resilient individuals may outperform those with lower resiliency on real-world tasks that require continuous attention. Future studies should determine whether the present findings generalize to other, operationally relevant tasks and additional cognitive domains.

Sleep in times of crises: A scoping review in the early days of the COVID-19 crisis.

During the early days of the pandemic and in the context of a seemingly unknown global threat, several potential major sleep disruptors were identified by sleep researchers and practitioners across the globe. The COVID-19 pandemic combined several features that, individually, had been shown to negatively affect sleep health in the general population. Those features included state of crisis, restrictions on in-person social interactions, as well as financial adversity. To address the lack of a comprehensive summary of sleep research across these three distinctive domains, we undertook three parallel systematic reviews based on the following themes: 1) Sleep in times of crises; 2) Sleep and social isolation; and 3) Sleep and economic uncertainty. Using a scoping review framework, we systematically identified and summarized findings from these three separated bodies of works. Potential moderating factors such as age, sex, ethnicity, socioeconomic status, psychological predisposition, occupation and other personal circumstances are also discussed. To conclude, we propose novel lines of research necessary to alleviate the short- and long-term impacts of the COVID-19 crises and highlight the need to prepare the deployment of sleep solutions in future crises.

Slow wave activity moderates the association between new learning and traumatic brain injury severity.

STUDY OBJECTIVES: Sleep-wake complaints and difficulties in making new learning are among the most persistent and challenging long-term sequelea following moderate to severe traumatic brain injury (TBI). Yet, it is unclear whether, and to what extent, sleep characteristics during the chronic stage of TBI contribute to sleep-wake and cognitive complaints. We aimed to characterize sleep architecture in chronic moderate to severe TBI adults and assess whether non-rapid eye movement slow wave activity (SWA) is associated to next day performance in episodic memory tasks according to TBI severity. METHODS: Forty-two moderate to severe TBI participants, 12-47 months post-injury, and 38 healthy controls were tested with one night of in-laboratory polysomnography, followed the next morning by questionnaires (sleep quality, fatigue, and sleepiness) and neuropsychological assessment. We used multiple regression analyses to assess the moderator effect of SWA power on TBI severity and next-day memory performance. RESULTS: We found that TBI participants reported worse sleep quality and fatigue, and had worse cognitive performance than controls. No between group differences were found on macro- and micro-architecture of sleep. However, SWA significantly interacted with TBI severity to explain next-day memory performance: higher SWA was more strongly associated to better memory performance in more severe TBI compared to milder TBI. CONCLUSIONS: This study provides evidence that the injured brain is able to produce macro- and micro-architecture of sleep comparable to what is seen in healthy controls. However, with increasing TBI severity, lower non-rapid eye movement SWA power is associated with reduced ability to learn and memorise new information the following day.

Efficacy of a Nasal Spray Containing Iota-Carrageenan in the Postexposure Prophylaxis of COVID-19 in Hospital Personnel Dedicated to Patients Care with COVID-19 Disease.

BACKGROUND: Iota-Carrageenan (I-C) is a sulfate polysaccharide synthesized by red algae, with demonstrated antiviral activity and clinical efficacy as nasal spray in the treatment of common cold. In vitro, I-C inhibits SARS-CoV-2 infection in cell culture. RESEARCH QUESTION: Can a nasal spray with Iota-Carrageenan be useful in the prophylaxis of COVID-19 in health care workers managing patients with COVID-19 disease? STUDY DESIGN AND METHODS: This is a pilot pragmatic multicenter, randomized, double-blind, placebo-controlled study assessing the use of a nasal spray containing I-C in the prophylaxis of COVID-19 in hospital personnel dedicated to care of COVID-19 patients. Clinically healthy physicians, nurses, kinesiologists and other health care providers managing patients hospitalized for COVID-19 were assigned in a 1:1 ratio to receive four daily doses of I-C spray or placebo for 21 days. The primary end point was clinical COVID-19, as confirmed by reverse transcriptase polymerase chain reaction testing, over a period of 21 days. The trial is registered at ClinicalTrials.gov (NCT04521322). RESULTS: A total of 394 individuals were randomly assigned to receive I-C or placebo. Both treatment groups had similar baseline characteristics. The incidence of COVID-19 differs significantly between subjects receiving the nasal spray with I-C (2 of 196 [1.0%]) and those receiving placebo (10 of 198 [5.0%]). Relative risk reduction: 79.8% (95% CI 5.3 to 95.4; p=0.03). Absolute risk reduction: 4% (95% CI 0.6 to 7.4). INTERPRETATION: In this pilot study a nasal spray with I-C showed significant efficacy in preventing COVID-19 in health care workers managing patients with COVID-19 disease. CLINICAL TRIALS REGISTRATION: NCT04521322.

Effect of cognitive load and emotional valence of distractors on performance during sleep extension and subsequent sleep deprivation.

STUDY OBJECTIVES: The purpose of the present study was to assess the extent to which sleep extension followed by sleep deprivation impacts performance on an attentional task with varying cognitive and attentional demands that influence decisions. METHODS: Task performance was assessed at baseline, after 1 week of sleep extension, and after 40 h of total sleep deprivation. RESULTS: One week of sleep extension resulted in improved performance, particularly for high cognitive load decisions regardless of the emotional salience of attentional distractors. Those who extended sleep the most relative to their habitual sleep duration showed the greatest improvement in general performance during sleep extension. However, a higher percentage of time spent in slow-wave sleep (SWS) on the last night of the sleep extension phase was negatively correlated with performance on more difficult high cognitive load items, possibly reflecting a relatively higher level of residual sleep need. Sleep deprivation generally resulted in impaired performance, with a nonsignificant trend toward greater performance decrements in the presence of emotionally salient distractors. Performance overall, but specifically for high cognitive load decisions, during total sleep deprivation was negatively correlated with longer sleep and higher SWS percentage during subsequent recovery sleep. CONCLUSIONS: The present findings suggest two possibilities: those who performed relatively poorly during sleep deprivation were more vulnerable because (1) they utilized mental resources (i.e. accrued sleep debt) at a relatively faster rate during wakefulness, and/or (2) they failed to "pay down" pre-study sleep debt to the same extent as better-performing participants during the preceding sleep extension phase.

Earlier shift in race pacing can predict future performance during a single-effort ultramarathon under sleep deprivation.

OBJECTIVE: We constructed research camps at single-effort ultramarathons (50 and 100 miles) in order to study human endurance capabilities under extreme sleep loss and stress. It takes > 24h, on average, to run 100 miles on minimal sleep, allowing us to construct 24h human performance profiles (HPP). METHODS: We collected performance data plotted across time (race splits) and distance (dropout rates; n=257), self-reported sleep and training patterns (n=83), and endpoint data on cardiovascular fitness/adaptation to total sleep deprivation and extreme exercise/stress (n=127). RESULTS: In general, we found that self-reported napping was higher for 100-miler versus 50-miler runners and that ultra-endurance racing may possibly pre-select for early morning risers. We also compared HPPs between the first 50 miles completed by all runners in order to examine amplitude and acrophase differences in performance using a cosinor model. We showed that even though all runners slowed down over time, runners who completed a 100-miler ultramarathon had an earlier acrophase shift in race pace compared to non-finishers. DISCUSSION: We were able to identify time-dependent predictions on overall performance under minimal sleep, warranting the ultramarathon athlete as a unique demographic for future study of sleep and chronobiological relationships in the real world.

Sleep misalignment and circadian rhythm impairment in long-haul bus drivers under a two-up operations system.

OBJECTIVES: The objective of the study was to describe working and sleep conditions and to assess how sleep opportunities are associated with obtained sleep and alertness, in a sample of long-haul bus drivers working with a two-up operations system. METHODS: Measures of subjective sleep and sleepiness, actigraphy, circadian temperature rhythm, and psychomotor vigilance tasks were obtained from a sample of 122 drivers from Argentina. Variables were compared between high and low fatigue risk groups, which were formed using a median split of a fatigue risk score. The score was calculated based on drivers' total working hours, maximum shift duration, minimum short break duration, maximum night work per seven days, and long break frequencies. RESULTS: Considering a standardized one-day period, sleep in the bus accounted for 1.9±0.1 h of total sleep (57±1% efficiency), sleep at destination for 1.6±0.2 h of total sleep (90±1% efficiency), and sleep at home for 3.8±0.2 h of total sleep (89±1% nap efficiency and 90±1% anchor sleep efficiency). In drivers exposed to high-risk working schedules, the circadian temperature rhythm was weaker (lower % of variance explained by the model) (22.0±1.7% vs. 27.6±2.0%, p <0.05) and without a significant acrophase. CONCLUSIONS: Drivers obtained a total amount of weekly sleep similar to the recommended levels for adults, but distributed at different locations and at different times during the day. High-risk working schedules were associated with disruption of circadian temperature rhythms. These results point out to the need of the implementation of shift-work scheduling strategies to minimize sleep misalignment and circadian desynchronization in long-haul bus drivers.

Precision Medicine for Sleep Loss and Fatigue Management.

Sleep loss is a widespread phenomenon and a public health threat. Sleep disorders, medical conditions, lifestyles, and occupational factors all contribute to insufficient sleep. Regardless of the underlying cause, insufficient sleep has well-defined consequences and the severity of said consequences partially influenced by individual characteristics. It is here where precision medicine needs to understand and define sleep insufficiency in hopes for personalizing medical approach to improve patient outcomes. Following a discussion on causes and consequences of sleep loss, this article discusses tools for assessing sleep sufficiency, mitigating strategies to sleep loss, and sleep loss in the context of fatigue management.

Sleep Patterns and Obesity: Hispanic Community Health Study/Study of Latinos Sueño Ancillar Study.

BACKGROUND: The relationship of poor sleep patterns to the increased risk of obesity has been reported, but the results are variable. This study evaluated the association between objectively measured sleep patterns and obesity in a representative adult population of Hispanic/Latino subjects living in the United States. METHODS: This cross-sectional study was an analysis of a multicenter, community-based cohort of 2,156 participants aged 18 to 64 years from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Recruitment was conducted in San Diego, California; Chicago, Illinois; Bronx, New York; and Miami, Florida. Models were controlled for age, sex, ethnic background, site, income, education, and apnea-hypopnea index. Seven days of wrist actigraphy data were collected. Obesity was defined as BMI ≥ 30 kg/m2, and abdominal obesity was defined as waist circumference ≥ 88 cm in women and ≥ 102 cm in men. Napping was defined as more than one 15-min nap per week. RESULTS: An inverse linear relationship was found between sleep duration and prevalence of obesity (P linear trend ≤ 0.01). A reduction of 1 h sleep increased obesity prevalence by 4.1% (95% CI, 1.6-6.6; P = .002) and abdominal obesity prevalence by 3.6% (95% CI, 1.1-6.1; P = .007). Daytime napping increased obesity prevalence by 10.4% (95% CI, 3.5-17.3; P = .004) and abdominal obesity prevalence by 7.1% (95% CI, 1.0-13.2; P = .02). CONCLUSIONS: In a population of young to older adult Hispanic/Latino subjects, we found an inverse linear association between sleep duration and the prevalence of obesity. Daytime napping was strongly associated with greater adiposity. Interventional and longitudinal studies are needed to better understand how abnormal sleep patterns contribute to the obesity epidemic.

A Review of Environmental Barriers to Obtaining Adequate Sleep in the Military Operational Context.

INTRODUCTION: Sleep loss is ubiquitous in military settings, and it can be deleterious to cognitive, physiological, and operational functioning. This is especially true in the military operational context (e.g., training, garrison, combat) where continuous operations prevent adequate time for rest and recuperation. Furthermore, even when servicemembers do have opportunities for sleep, environmental disruptors in the military operational context make it difficult to obtain restorative sleep. Such environmental disruptors are potentially preventable or reversible, yet there is little public awareness of how to minimize or eliminate these sleep disruptors. Therefore, the goal of this review was to outline prominent environmental sleep disruptors, describe how they occur in the military operational context, and also discuss feasible strategies to mitigate these disruptors. MATERIALS AND METHODS: We discuss four factors - light, noise, temperature, and air pollution - that have previously been identified as prominent sleep disruptors in non-military settings. Additionally, we extracted publicly-available yearly temperature and pollution data, from the National Oceanic and Atmospheric Association and the Environmental Protection Agency, respectively, for major prominent military installations in the continental US in order to identify the sites at which servicemembers are at the greatest risk for environmental sleep disruptions. RESULTS: Based on previous literature, we concluded light and noise are the most easily mitigatable sleep-disrupting environmental factors. Air pollution and temperature, on the other hand, are more difficult to mitigate. We also propose that harsh/uncomfortable sleeping surface is a fifth critical, previously unexplored sleep disruptor in the military operational context. Furthermore, we identified several problematic military sites for air pollution for temperature. Specifically, each branch has major installations located in regions with extreme heat (especially the Army), and each branch has at least one major installation in a high air pollution region. These findings show that even when in training or garrison in the US, military servicemembers are at risk for having sleep disruption due to environmental factors. CONCLUSIONS: Environmental disruptors, such as light, noise, temperature, and air pollution, can negatively impact sleep in the military operational context. Simple, feasible steps can be taken to reduce sleep disruptions that are caused by light and noise. Yet there is a need for research and development on tools to mitigate air pollution, extreme temperatures, and inhospitable sleeping surfaces. Leadership at the discussed military bases and training facilities should focus on improving the sleep environment for individuals under their command. Such interventions could ultimately improve warfighter health, wellness, and operational performance, leading to greater warfighter readiness and lethality.

Sleep extension reduces pain sensitivity.

INTRODUCTION: Insufficient sleep increases pain sensitivity in healthy individuals. Additionally, extending sleep (eg, increasing nocturnal sleep time or adding a mid-day nap) has been shown to restore pain sensitivity to baseline levels in sleep deprived/restricted individuals. Whether sleep extension can reduce pain sensitivity beyond baseline levels in non-sleep restricted/deprived individuals remains unknown. METHODS: In a sample of 27 healthy, pain-free, normally-sleeping individuals (17 males, mean age ∼24 yrs), we examined the impact of five nights of sleep extension on pain sensitivity. Pain threshold (elapsed time until the participant reported pain) and pain tolerance (total time the participant kept the hand submerged in the cold water) were measured using the Cold Pressor Task. Furthermore, we assessed the extent to which self-reported sleep amount in relation to the minimal subjective sleep requirement for adequate performance (sleep credit) was associated with pain sensitivity changes. RESULTS: On average individuals slept almost 2 extra hours per night. Our results indicate that sleep extension increases pain tolerance beyond baseline levels. However, sleep extension did not impact pain threshold. We also found that individuals with a smaller sleep credit (ie, those who habitually obtain less sleep than they feel they need) experienced greater increases in pain tolerance after extending sleep. CONCLUSIONS: The present findings suggest that sleep extension may increase pain tolerance but not pain threshold in healthy individuals who normally sleep the recommended amount. Our findings also support the idea that sleep credit may be a strong indicator of sleep debt in the context of pain sensitivity.