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We assessed the utility of the 3-section, fixed, 4hrs-on/8hrs-off watchstanding schedule on a ship of the Swedish Royal Navy (HSwMS ORIOΝ). Data from the ORIOΝ (n=12 sailors) were compared with data from three USN vessels (n=22). Daily sleep duration, number of sleep episodes/day, and daily work duration were equivalent in the two samples. Compared to their USN peers, however, sailors on the ORION were more alert, reported better sleep quality, less severe insomnia symptoms, and better mood. Also, sailors on the ORION were faster and made fewer errors on the psychomotor vigilance task (PVT). Analysis of daily activities suggests that Swedish sailors may have felt and performed better because sailors working night shifts were allowed to wake up later. Our findings suggest the sailor well-being when standing watch on the fixed 4/8 can be improved when sailors are allowed flexible wake up times in the morning after a night shift.

Introduction: Public transportation is an essential societal function in crisis situations like the coronavirus disease 2019 (COVID-19) pandemic. Bus drivers and other public transport workers are essential workers that need to keep working despite the risk of contagion. The SARS-CoV-2 virus may pose an occupational health risk to public transport workers and especially to bus drivers as they interact with passengers in a confined area. By analyzing antibodies towards SARS-CoV-2 proteins in blood samples it is possible to measure if an individual has been infected by COVID-19. Here, we report the prevalence of antibodies among bus drivers and other public transport employees in Stockholm, Sweden and relate it to socio-demographic factors.Methods: Seroprevalence of IgG antibodies towards SARS-CoV-2 proteins was investigated in a sample of 262 non-vaccinated public transport workers (182 men and 40 women) recruited between April 26 and May 7, 2021. Most of the participants were bus drivers (n = 222). The relationship between socio-demographic factors and seroprevalence was investigated with logistic regression.Results: The seroprevalence was 50% in the total sample of public transport workers. Among bus drivers, 51% were seropositive compared to 44% seropositive among the other public transport workers. The difference was not significant. The seroprevalence was higher than the national seroprevalence in Sweden during the same period (18.3% in non-vaccinated people aged 20-64 years). The logistic regression model using Wald forward selection showed that men had a higher risk of being seropositive (OR 2.7, 95% CI 1.3 - 5.8) and there was a higher risk with increasing number of people in the household (OR 1.3, 95% CI 1.1 - 1.6).Conclusions: These findings could imply an occupational risk for COVID-19 infection among public transport workers. Infection control measures are warranted during virus epidemics to assure bus drives safety and reduce transmission in public transport. Funding Agencies|AFA Insurance [200225]

Driver fatigue detection systems have potential to improve road safety by preventing crashes and saving lives. Conventional driver monitoring systems based on driving performance and facial features may be challenged by the application of automated driving systems. This limitation could potentially be overcome by monitoring systems based on physiological measurements. Heart rate variability (HRV) is a physiological marker of interest for detecting driver fatigue that can be measured during real life driving. This systematic review investigates the relationship between HRV measures and driver fatigue, as well as the performance of HRV based fatigue detection systems. With the applied eligibility criteria, 18 articles were identified in this review. Inconsistent results can be found within the studies that investigated differences of HRV measures between alert and fatigued drivers. For studies that developed HRV based fatigue detection systems, the detection performance showed a large variation, where the detection accuracy ranged from 44% to 100%. The inconsistency and variation of the results can be caused by differences in several key aspects in the study designs. Progress in this field is needed to determine the relationship between HRV and different fatigue causal factors and its connection to driver performance. To be deployed, HRV-based fatigue detection systems need to be thoroughly tested in real life conditions with good coverage of relevant driving scenarios and a sufficient number of participants.

Burnout constitutes a serious health concern in the modern working environment. It is a stress-related condition that has developed as a result of a prolonged psychosocial stress exposure causing a persistent mismatch between demands and resources. The main symptom is emotional exhaustion, but physical fatigue, diminished professional efficacy, cynicism, and cognitive impairments are also associated with this condition. Burnout has been used both as a psychologic term in occupational settings and as a clinical diagnosis in patient populations, and there is currently no universally accepted definition and diagnostic criteria of burnout. It has been hypothesized that the two main stress response systems, the autonomic nervous system (ANS) and the hypothalamus-pituitary-adrenal axis (HPA axis), are involved in the pathogenesis of burnout. A common hypothesis is that in the early stages of chronic stress, the HPA axis and sympathetic ANS activity tend to be higher, while it will decrease with a longer duration of chronic stress to ultimately reach a state of hypoactivity in clinical burnout. The current research in this field shows many contradictory results. Thus there is no compelling evidence of either ANS or HPA dysfunction in burnout. However, there is partial support for the hypothesis of HPA and sympathetic hyperactivity in early stages, and HPA hyporeactivity and low vagal activity in more severe burnout cases, but high-quality studies investigating the causal links are still lacking.

BACKGROUND: Many workers routinely transition between day and night shiftsincluding pilots, where night flights are commonly considered more stressful. The physiological toll from this transition is not fully understood, though fatigue is a factor in many aviation accidents. This research investigated the changes in physiological markers of stress and cognitive performance as F-22 pilots transitioned from day flying to night flying.METHODS: There were 17 fully-qualified F-22 pilots who took part in a 2-wk data collection using salivary swabs, wrist-worn activity monitors, the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) inventory, and a go/no-go (GNG) test.RESULTS: No differences were found in comparing day and night flying on the GNG reaction time/accuracy, NASA-TLX scores, or sleep quantity. Cortisol levels were significantly higher than civilian levels in all experimental conditions and control days. Participants had higher than predicted cortisol levels postflight in the day-flying condition and lower than predicted cortisol levels postflight in the night-flying condition, relative to levels from control day patterns. We also found smaller changes in cortisol (pre- to postflight) in the day-flying condition for those with more F-22 experience. Finally, we found a negative correlation between Perceived Stress Scale scores and age of pilots (r 0.72).DISCUSSION: We hypothesized that the night-flying environment would be more stressful, but our results disputed this claim. Our results suggest day flying elicits more of a stress response; however, a larger sample size is required to verify results. Preliminary findings of potential stress adaptation may suggest stress adaptation in the F-22 community needs further investigation.Combs EK, Dahlman AS, Shattuck NL, Heissel JA, Whitaker LR. Physiological and cognitive performance in F-22 pilots during day and night flying. Aerosp Med Hum Perform. 2021; 92(5):303311.

Burnout constitutes a serious health concern in the modern working environment. It is a stress-related condition that has developed as a result of a prolonged psychosocial stress exposure causing a persistent mismatch between demands and resources. The main symptom is emotional exhaustion, but physical fatigue, diminished professional efficacy, cynicism, and cognitive impairments are also associated with this condition. Burnout has been used both as a psychologic term in occupational settings and as a clinical diagnosis in patient populations, and there is currently no universally accepted definition and diagnostic criteria of burnout. It has been hypothesized that the two main stress response systems, the autonomic nervous system (ANS) and the hypothalamus-pituitary-adrenal axis (HPA axis), are involved in the pathogenesis of burnout. A common hypothesis is that in the early stages of chronic stress, the HPA axis and sympathetic ANS activity tend to be higher, while it will decrease with a longer duration of chronic stress to ultimately reach a state of hypoactivity in clinical burnout. The current research in this field shows many contradictory results. Thus there is no compelling evidence of either ANS or HPA dysfunction in burnout. However, there is partial support for the hypothesis of HPA and sympathetic hyperactivity in early stages, and HPA hyporeactivity and low vagal activity in more severe burnout cases, but high-quality studies investigating the causal links are still lacking.

Background Exercise training is suggested to have a stress-buffering effect on physiological reactions to acute stress. The so-called cross-stressor adaptation hypothesis is one of many theories behind the plausible effects, proposing that the attenuated physiological reaction seen in trained individuals in response to acute exercise is also seen when the individual is exposed to acute psychosocial stress. However, few randomized controlled trials (RCT) are available in this field. Therefore, the aim of the present trial was to study the effects of a 6-month aerobic exercise intervention on the physiological response to acute laboratory stress. Methods A two-armed RCT including untrained but healthy individuals aged 20–50 years was conducted. Assessments included a peak oxygen uptake test and a psychosocial stress test (the Trier Social Stress Test). A total of 88 participants went through both baseline and follow-up measures (48 in the intervention group and 40 in the control group) with a similar proportion of women and men (20 women and 28 men in the intervention group and 18 women and 22 men in the control group). Outcome measures were adrenocorticotrophic hormone, cortisol, systolic and diastolic blood pressure, and heart rate responses to acute psychosocial stress. Results Oxygen uptake and time-to-exhaustion increased significantly following the intervention, while a decrease was seen in the control group. The analyses showed attenuated responses to acute psychosocial stress for all variables in both groups at follow-up, with no differences between the groups. No correlation was seen between amount of exercise training and reactivity to the stress test. Despite the increased oxygen uptake in the intervention group, no differences were seen between the groups for any of the outcome variables at follow-up. Conclusions In this study, the cross-stressor adaptation hypothesis could not be confirmed. Both groups showed decreased reactions indicating a habituation to the stress test. Trial registration ClinicalTrials.gov NCT02051127. Registered on 31 January 2014—retrospectively registered.

As part of a broader study, this work investigates if habitual exercise protects against mood deterioration and daytime sleepiness in Sailors during underway operations. Previous work has shown that unfavorable watchstanding schedules have negative effects on sleep quality, subjective levels of fatigue, mood, and psychomotor vigilance performance. The participants were crewmembers of a U.S. Navy aircraft carrier (N=193), working on two different watchstanding schedules. Epworth Sleepiness Scale (ESS) and profile of mood state (POMS) scores were compared between participants who reported exercising < 3 times/week and ≥3 times/week. During the course of the underway, ESS and POMS scores changed more favorably for the crewmembers who exercised 3 or more times/week compared to their peers who exercised less. The effect of working out was more prominent in the less favorable shift schedule. These results suggest that habitual exercise can be a protective buffer against some of the negative effects of watchstanding while underway.

Growth factors, such as vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF), and neurotrophic factors, including brain-derived neurotophic factor (BDNF), have attracted attention in studies of the biological effects of long-term stress exposure due to their neuroprotective roles. This study investigated whether circulating levels of EGF, VEGF and BDNF were altered in individuals with stress-related exhaustion disorder. Forty patients diagnosed with exhaustion disorder and 40 healthy subjects (50% women) provided fasting blood samples for analysis of EGF, VEGF, and BDNF in plasma. We found significantly lower levels of EGF, VEGF, and BDNF in patients with ED compared to healthy controls. This pattern was seen in both male and female patients. Given the important roles of BDNF and VEGF for brain plasticity and neurogenesis, decreased levels after long-term stress exposure could indicate increased risk of neuronal damage and cognitive impairments in this patient group.

Burnout has several different definitions, and attempts have been made to discriminate between burnout as a psychological construct and burnout as a clinical entity. A large body of research has focused on elucidating the biological link between stress exposure and burnout and/or finding a clinically usable biomarker for burnout. The objective of this narrative review is to summarize the main endocrine and immune findings in relation to burnout. The literature has primarily focused on dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. However, albeit the large body of studies, it cannot be concluded that clear effects are seen on HPA axis function in people with burnout. The HPA axis and anabolic acute reactivity to stress might be affected in clinical burnout. Plausible, effects of chronic stress might rather be seen when measuring responses to acute stress rather than resting state hormonal levels. Studies on other hormones, including thyroid hormones, prolactin and growth hormone in burnout subjects are inconclusive. It is important to note that this field is faced with many methodological challenges, one being the diurnal and pulsatile nature of many of the hormones of interest, including cortisol, which is not always considered. Another challenge is the heterogeneity regarding definitions and measurements of stress and burnout. Existing studies on burnout and immune function are heterogeneous regarding the results and no firm conclusion can be made if clinically relevant immune changes are present in burnout subjects. An overall conclusion is that existing research cannot confirm any homogenous reliable endocrinological or immunological changes related to burnout.

Sleep is unquestionably a critical commodity for humans, yet research indicates a growing sleep debt prevalent in many segments of society. Performance and health have been shown to be profoundly affected by lack of sleep; we ignore the need for sleep at our peril. Research conducted at the Naval Postgraduate School over the past two decades has demonstrated that members of our military service are chronically sleep deprived. Many of them have insufficient opportunities to sleep due to long work hours and operational commitments. In addition, because of the 24/7 nature of the military mission, opportunities for sleep often occur during circadian-misaligned time periods. Military sleeping conditions are less than ideal, further exacerbating a chronic sleep debt.

The aim was to use metabolomics to compare metabolic reactions to acute stress between clinical burnout patients and healthy individuals. Fifteen burnout patients (6 women) and 15 controls (8 women ...

BackgroundThis paper describes the protocol and methodological prerequisites for a randomised controlled exercise intervention. Selected baseline data from the study are also presented, demonstrating some methodological challenges related to exercise intervention trials. The aim of the trial was to study the effects of exercise training on physiological responses to acute psychosocial stress in untrained individuals.MethodsIndividuals with a low level of physical activity were invited to participate in an exercise intervention lasting for 6 months. A total of 119 participants were included and went through a peak oxygen uptake test and a psychosocial stress test at baseline. Adrenocorticotropic hormone (ACTH) and cortisol were measured in connection to the stress test to identify the physiological response.ResultsAlmost 90% of the participants reported themselves as untrained, but results from the objectively measured oxygen uptake did not seem to correspond to the reported sedentary lifestyle. The primary outcome measures at baseline varied between individuals. The mean change from pre-test to peak value was 214% for ACTH and 94% for cortisol. Of these, 13 individuals did not respond in ACTH and/or and cortisol.DiscussionSupposedly untrained individuals seeking participation in an exercise intervention might not be as untrained as they report, a methodological consideration of importance when evaluating the effects of training. Another important consideration is related to the primary outcome measure, which should be measurable and possible to affect. Absence of reaction at baseline means that changes can only be detected as an increased reaction.