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1.
Hum Factors ; : 187208221086686, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35549578

RESUMO

OBJECTIVE: This project aimed to assess the impact of an 8-day military training exercise on cognitive performance, and track its recovery in periods of reduced training load and partially restored sleep. BACKGROUND: Military personnel often work in challenging multi-stressor environments, where sleep loss is inevitable. Sleep loss can impair multiple cognitive domains, which can have disastrous consequences in military contexts. METHOD: A total of 57 male and female soldiers undergoing the Australian Army combat engineer Initial Employment Training course were recruited and tracked over a 16-day study period which included an 8-day field-based military training exercise. Cognitive performance was assessed via a computerised battery at seven time points across four sequential study periods; 1) baseline (PRE), 2) military field training exercise which included total sleep deprivation (EX-FIELD), 3) training exercise at simulated base with restricted sleep opportunities (EX-BASE), and 4) a 3-day recovery period (REC). Subjective load, fatigue, and sleep were evaluated continuously via questionnaire and actigraphy. RESULTS: Psychomotor speed, reaction time, visual tracking and vigilance were impaired following the EX-FIELD period (p < 0.05). The majority of affected measures recovered 2 days following EX-FIELD, being no different in EX-BASE compared to PRE. CONCLUSION: The sensitivity of the cognitive tests to sleep restriction, and recovery, indicates they can help assess operational readiness in military personnel. Future studies should explore other indicators of, and strategies to preserve, operational readiness in military personnel. APPLICATION: This study highlights the impact of work-induced fatigue on cognitive performance, and would interest authorities seeking to preserve operational readiness.

2.
PLoS One ; 17(3): e0265121, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35271678

RESUMO

OBJECTIVES: Military personnel are required to train and operate in challenging multi-stressor environments, which can affect hormonal levels, and subsequently compromise performance and recovery. The aims of this project were to 1) assess the impact of an eight-day military training exercise on salivary cortisol and testosterone, 2) track the recovery of these hormones during a period of reduced training. METHODS: This was a prospective study whereby 30 soldiers (n = 27 men, n = 3 women) undergoing the Australian Army combat engineer 'Initial Employment Training' course were recruited and tracked over a 16-day study period which included an eight-day military training exercise. Non-stimulated saliva samples were collected at waking, 30 min post waking, and bedtime on days 1, 5, 9, 13, 15; measures of subjective load were collected on the same days. Sleep was measured continuously via actigraphy, across four sequential study periods; 1) baseline (PRE: days 1-4), 2) field training with total sleep deprivation (EX-FIELD: days 5-8), 3) training at simulated base camp with sleep restriction (EX-BASE: days 9-12), and 4) a three-day recovery period (REC: days 13-15). RESULTS: Morning cortisol concentrations were lower following EX-FIELD (p<0.05) compared to the end of REC. Training in the field diminished testosterone concentrations (p<0.05), but levels recovered within four days. Bedtime testosterone/cortisol ratios decreased following EX-FIELD and did not return to pre-training levels. CONCLUSIONS: The sensitivity of testosterone levels and the testosterone/cortisol ratio to the period of field training suggests they may be useful indicators of a soldier's state of physiological strain, or capacity, however inter-individual differences in response to a multi-stressor environment need to be considered.


Assuntos
Hidrocortisona , Militares , Austrália , Feminino , Humanos , Masculino , Estudos Prospectivos , Saliva , Testosterona
3.
Eur J Sport Sci ; 22(1): 72-86, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34346851

RESUMO

Adaptation to military operational stress is a complex physiological response that calls upon the sympathetic nervous system (SNS), hypothalamic pituitary adrenal (HPA) axis and immune system, to create a delicate balance between anabolism and catabolism and meet the demands of an ever-changing environment. As such, resilience, the ability to withstand and overcome the negative impact of stress on military performance, is likely grounded in an appropriate biological adaptation to encountered stressors. Neuroendocrine [i.e. cortisol, epinephrine (EPI), norepinephrine (NE), neuropeptide-Y (NPY), and brain derived neurotropic factor (BDNF)], inflammatory [i.e. interleukin 6 (IL-6), IL-1ß, IL-4, IL-10 and tumour necrosis factor (TNF)-α], as well as growth and anabolic [i.e. insulin-like growth factor-I (IGF-I), testosterone, and dehydroepiandrosterone (DHEA)] biomarkers independently and interactively function in stress adaptations that are associated with a soldier's physical and psychological performance. In this narrative review, we detail biomarkers across neuroendocrine, inflammatory, and growth stimulating domains to better elucidate the biological basis of a resilient soldier. The findings from the reviewed studies indicate that military readiness and resiliency may be enhanced through better homeostatic control, better regulated inflammatory responses, and balanced anabolic/catabolic processes. It is unlikely that one class of biomarkers is better for assessing physiological resilience. Therefore, a biomarker panel that can account for appropriate balance across these domains may be superior in developing monitoring frameworks. Real-time physiological monitoring to assess biomarkers associated with resilience will be possible pending more sophisticated technologies and provide a field-expedient application for early identification and intervention of at-risk soldiers to improve military resiliency.


Assuntos
Militares , Biomarcadores/metabolismo , Humanos , Hidrocortisona/metabolismo , Sistema Hipotálamo-Hipofisário/metabolismo , Militares/psicologia , Sistema Hipófise-Suprarrenal/metabolismo , Estresse Psicológico
4.
Ergonomics ; 64(7): 856-868, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33523762

RESUMO

This study examined how objective measures of sleep change across shift-cycles, and the impact of this on sleep quality and fatigue. Forty maritime pilots were recruited from Australian ports. Sleep wake-behaviour (timing and length), and self-reported sleep quality and fatigue, were assessed to determine any impact of roster status and 'on-call' status. On-roster pilots experienced reduced night time sleep duration compared to those off-roster (57 ± 8.8 min), while working on-call also diminished night time sleep duration (126 ± 11.3 min) and quality, compared to workers not on-call. Fatigue scores indicated that participants were not fully recovered prior to commencing rostered night shift, while sleep quality was significantly worse following sleep that occurred after a night shift, compared to after a day shift. These findings potentially support workplace negotiations to change future shift cycles, and to adopt monitoring systems that may mitigate the risk of fatigue-related accidents and chronic health outcomes. Practitioner summary: Long and irregular work hours of maritime pilotage can compromise worker performance and safety. This observational study found that on-roster pilots experience reduced sleep duration compared to those off-roster, while working on-call further diminishes sleep duration and quality. Future workload/fatigue monitoring systems may mitigate fatigue-related accidents and adverse chronic health outcomes. Abbreviations: ANOVA: analysis of variance; ANCOVA: analysis of covariance; BMI: body mass index; CVD: cardiovascular disease; h: hours; mins: minutes; SE: standard error of the mean; SD: standard deviation; SO: sleep opportunities; TST: total sleep time; WASO: wake after sleep onset.


Assuntos
Pilotos , Jornada de Trabalho em Turnos , Austrália , Fadiga/etiologia , Humanos , Admissão e Escalonamento de Pessoal , Sono , Tolerância ao Trabalho Programado
5.
Eur J Appl Physiol ; 121(3): 849-860, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33389139

RESUMO

PURPOSE: Stress, anxiety and physical exertion are all closely linked to well-being, and each can alter immune function. Diminished well-being has been observed during military training, however there is mixed evidence regarding whether concomitant changes in inflammatory markers occur, with these phenomena indicating potential maladaptive responses to imposed training loads. The aims of this project were (1) assess changes in inflammation and subjective well-being across a 12-week basic military training (BMT) program, and (2) evaluate relationships between circulating inflammatory markers and well-being. METHODS: A total of 37 men and women undergoing 12 weeks of BMT in Australia were recruited. Well-being was assessed via questionnaire (DASS-21), and plasma samples were collected for the analysis of inflammatory cytokines [interleukin (IL)-4, IL-6, IL-1ß, IL-8, IL-10, and tumor necrosis factor (TNF)-α] at weeks 1, 4, 8 and 12. Data were analysed using general linear mixed models. RESULTS: Depression, anxiety and stress subscale scores all significantly improved (all P ≤ 0.001), and TNF-α decreased (P = 0.031) across time. Compared to baseline (week 1), significant decreases in associations between depression and IL-10, anxiety and IL-10, and stress and IL-10, IL-4 IL-6 and TNF-α (all P < 0.05), were detected across BMT. CONCLUSION: The BMT program appears to support improved well-being over the 12 weeks, with minimal perturbation to inflammatory markers. Biomarkers and well-being displayed consistent associations and may have utility as psychophysiological indicators of health status in military research, however for now, subjective measures may represent more cost-effective proxies for ongoing monitoring of military personnel.


Assuntos
Mediadores da Inflamação/metabolismo , Inflamação/metabolismo , Militares , Adulto , Biomarcadores/metabolismo , Citocinas/imunologia , Citocinas/metabolismo , Feminino , Humanos , Inflamação/imunologia , Inflamação/patologia , Mediadores da Inflamação/imunologia , Estudos Longitudinais , Masculino , Adulto Jovem
6.
J Occup Environ Med ; 62(2): 145-148, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31764604

RESUMO

OBJECTIVES: The purpose of this study was to determine the inflammatory response to a 12-hour wildfire suppression shift, in firefighters attending the "Black Saturday" natural disaster. METHODS: Thirty-eight male volunteer firefighters provided venous blood samples before and after a 12-hour firefighting shift. Pre- to post-shift changes in pro-inflammatory (Interleukin [IL]-1ß, IL-2, IL-6, IL-8, IL-12P70, granulocyte macrophage-colony stimulating factor [GM-CSF], tumor necrosis factor-alpha [TNF-α], interferon-gamma [IFNγ]), and anti-inflammatory (IL-4, IL-5, IL-7, IL-10, IL-13) cytokines were measured with paired sample t tests, or Wilcoxon t tests for non-parametric data. RESULTS: Interleukin (IL)-6 (P = 0.003) and IL-8 (P = 0.017) were significantly increased following 12-hours of wildfire suppression. There was also a significant decrease in IL-10 (P = 0.021). CONCLUSIONS: The observed acute inflammatory response may have resulted from multiple stressors including physical exertion, thermal strain, or smoke inhalation experienced during the shift, and may be a necessary response for the body to adapt to stressor exposure.


Assuntos
Bombeiros , Inflamação , Exposição Ocupacional/análise , Incêndios Florestais , Citocinas , Fator Estimulador de Colônias de Granulócitos e Macrófagos , Humanos , Interferon gama , Interleucina-10 , Interleucina-1beta , Fator de Necrose Tumoral alfa
7.
Exp Gerontol ; 125: 110662, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31323254

RESUMO

OBJECTIVES: Stressful experiences, poor self-rated health, and negative emotional states have been implicated with higher levels of inflammatory markers and lower levels of neurotrophic factors in some healthy adults and clinical populations, but these relationships are unclear in the elderly. This study aimed to identify the associations between systemic inflammatory and neurological markers with well-being and health-related quality of life (HR-QoL) in independently living elderly people. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: A total of 268 men and women aged ≥65 years living independently in retirement communities in Melbourne, Australia. MEASURES: Questionnaires were used to assess HR-QoL [Short Form (SF)-36 version 2] and well-being (Personal Wellbeing Index). Serum inflammatory cytokines [interleukin (IL)-4, IL-6, IL-1ß, IL-8, IL-10, tumor necrosis factor (TNF)-α, and high sensitive C-reactive protein (hs-CRP)] were standardised to Z-scores and used to calculate pro- and anti-inflammatory composite score and an overall composite inflammatory index. Plasma levels of the neurological markers amyloid ß (1-40) and amyloid ß (1-42), brain derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF), were also assessed. RESULTS: No significant associations were found between any inflammatory or neurological marker with HR-OoL or well-being, with the exception that lower perceptions of the HR-QoL vitality subscale were associated with higher levels of hs-CRP [unstandardized beta-coefficient (ß): -1.50; 95% CI: -2.53, -0.46; P = 0.004] and Z-scores in the pro-inflammatory composite score (ß = -2.06; 95% CI: -3.49, -0.62; P = 0.005). CONCLUSIONS/IMPLICATIONS: In elderly people residing in independent living retirement communities, there was no consistent evidence indicating that circulating inflammatory or neurological markers were associated with the key physical or mental HR-QoL domains or overall well-being. This suggests that these biomarkers may not be effective predictors in relatively healthy communities, and may be more beneficial in frail or clinical populations. Clinical Trials registry: Australian New Zealand Clinical Trials Registry (ACTRN12613001161718). http://www.anzctr.org.au/.


Assuntos
Biomarcadores/sangue , Citocinas/sangue , Envelhecimento Saudável/sangue , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/sangue , Fator Neurotrófico Derivado do Encéfalo/sangue , Proteína C-Reativa/metabolismo , Estudos Transversais , Feminino , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Fator A de Crescimento do Endotélio Vascular/sangue
8.
PLoS One ; 14(6): e0218732, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31226144

RESUMO

PURPOSE: Responding to emergency alarms is a daily occurrence for personnel in safety-critical occupations, and is associated with negative health outcomes in this population. The purpose of the present study was to determine the acute inflammatory response to an isolated emergency alarm mobilisation in both day and night conditions. METHODS: Sixteen healthy males (mean age 25 ± 4 years) spent four days and nights in a sleep laboratory and were required to mobilise to an emergency alarm either during the day (1558 h), or from nocturnal sleep (0358 h). Pro (TNF-α, IL-1ß, IL-8, IL-6) and anti-inflammatory (IL-4 and IL-10) cytokine responses to each alarm mobilisation were compared to time-matched control conditions without the alarm and mobilisation stimulus. RESULTS: Analysis revealed no significant drift of cytokine levels at 1400 h across the study (P≥0.139). The plasma concentration of anti-inflammatory cytokine IL-4 was 84% greater in the 2-h sampling period following night alarm mobilisation compared to a night control of gentle awakening (P = 0.049), no other condition-by-time interactions were observed. The majority of inflammatory concentrations did not significantly change between alarm mobilisation and control conditions, in either day or night trials. CONCLUSIONS: These findings may reflect the lack of a true emergency (and the perceived stress) for the alarm mobilisation, together with the neutralising effect of different circadian biorhythms on inflammatory cytokine concentrations.


Assuntos
Ritmo Circadiano/fisiologia , Citocinas/sangue , Emergências , Inflamação/sangue , Sono/fisiologia , Vigília/fisiologia , Adulto , Estudos Cross-Over , Citocinas/análise , Emergências/psicologia , Serviço Hospitalar de Emergência , Humanos , Hidrocortisona/sangue , Inflamação/etiologia , Masculino , Ruído Ocupacional , Treinamento por Simulação , Privação do Sono/sangue , Estresse Fisiológico/fisiologia , Adulto Jovem
9.
BMC Med Res Methodol ; 18(1): 173, 2018 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-30572835

RESUMO

BACKGROUND: Randomized controlled trials (RCTs) provide the highest level of scientific evidence, but successful participant recruitment is critical to ensure the external and internal validity of results. This study describes the strategies associated with recruiting older adults at increased falls risk residing in retirement villages into an 18-month cluster RCT designed to evaluate the effects of a dual-task exercise program on falls and physical and cognitive function. METHODS: Recruitment of adults aged ≥65 at increased falls risk residing within retirement villages (size 60-350 residents) was initially designed to occur over 12 months using two distinct cohorts (C). Recruitment occurred via a three-stage approach that included liaising with: 1) village operators, 2) independent village managers, and 3) residents. To recruit residents, a variety of different approaches were used, including distribution of information pack, on-site presentations, free muscle and functional testing, and posters displayed in common areas. RESULTS: Due to challenges with recruitment, three cohorts were established between February 2014 and April 2015 (14 months). Sixty retirement villages were initially invited, of which 32 declined or did not respond, leaving 28 villages that expressed interest. A total of 3947 individual letters of invitation were subsequently distributed to residents of these villages, from which 517 (13.1%) expressions of interest (EOI) were received. Across three cohorts with different recruitment strategies adopted there were only modest differences in the number of EOI received (10.5 to 15.3%), which suggests that no particular recruitment approach was most effective. Following the initial screening of these residents, 398 (77.0%) participants were deemed eligible to participate, but a final sample of 300 (58.0% of the 517 EOI) consented and was randomized; 7.6% of the 3947 residents invited. Principal reasons for not participating, despite being eligible, were poor health, lack of time and no GP approval. CONCLUSION: This study highlights that there are significant challenges associated with recruiting sufficient numbers of older adults from independent living retirement villages into an exercise intervention designed to improve health and well-being. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613001 161718 . Date registered 23rd October 2013.


Assuntos
Acidentes por Quedas/prevenção & controle , Terapia por Exercício/métodos , Exercício Físico/fisiologia , Seleção de Pacientes , Aposentadoria/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Coleta de Dados/métodos , Coleta de Dados/estatística & dados numéricos , Feminino , Instituição de Longa Permanência para Idosos , Humanos , Masculino , Casas de Saúde , Participação do Paciente/estatística & dados numéricos , Fatores de Risco , Fatores de Tempo
10.
Front Aging Neurosci ; 9: 368, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29163146

RESUMO

Emerging research indicates that exercise combined with cognitive training may improve cognitive function in older adults. Typically these programs have incorporated sequential training, where exercise and cognitive training are undertaken separately. However, simultaneous or dual-task training, where cognitive and/or motor training are performed simultaneously with exercise, may offer greater benefits. This review summary provides an overview of the effects of combined simultaneous vs. sequential training on cognitive function in older adults. Based on the available evidence, there are inconsistent findings with regard to the cognitive benefits of sequential training in comparison to cognitive or exercise training alone. In contrast, simultaneous training interventions, particularly multimodal exercise programs in combination with secondary tasks regulated by sensory cues, have significantly improved cognition in both healthy older and clinical populations. However, further research is needed to determine the optimal characteristics of a successful simultaneous training program for optimizing cognitive function in older people.

11.
Noise Health ; 18(82): 150-6, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27157688

RESUMO

The purpose of this study was to investigate the acute physiological stress response to an emergency alarm and mobilization during the day and at night. Sixteen healthy males aged 25 ± 4 years (mean ± SD) spent four consecutive days and nights in a sleep laboratory. This research used a within-participants design with repeated measures for time, alarm condition (alarm or control), and trial (day or night). When an alarm sounded, participants were required to mobilize immediately. Saliva samples for cortisol analysis were collected 0 min, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min after mobilization, and at corresponding times in control conditions. Heart rate was measured continuously throughout the study. Heart rate was higher in the day (F(20,442) = 9.140, P < 0.001) and night (F(23,459) = 8.356, P < 0.001) alarm conditions compared to the respective control conditions. There was no difference in saliva cortisol between day alarm and day control conditions. Cortisol was higher (F(6,183) = 2.450, P < 0.001) following the night alarm and mobilization compared to the night control condition. The magnitude of difference in cortisol between night control and night alarm conditions was greater (F(6,174) = 4.071, P < 0.001) than the magnitude of difference between the day control and day alarm conditions. The augmented heart rate response to the day and night alarms supports previous observations in field settings. Variations in the cortisol responses between conditions across the day and night may relate to differences in participants' ability to interpret the alarm when sleeping versus when awake.


Assuntos
Frequência Cardíaca/fisiologia , Hidrocortisona/metabolismo , Atividade Motora/fisiologia , Sono/fisiologia , Estresse Fisiológico/fisiologia , Vigília/fisiologia , Adulto , Ritmo Circadiano/fisiologia , Alarmes Clínicos , Humanos , Masculino , Saliva , Adulto Jovem
12.
Trials ; 16: 120, 2015 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-25872612

RESUMO

BACKGROUND: Falls are a major public health concern with at least one third of people aged 65 years and over falling at least once per year, and half of these will fall repeatedly, which can lead to injury, pain, loss of function and independence, reduced quality of life and even death. Although the causes of falls are varied and complex, the age-related loss in muscle power has emerged as a useful predictor of disability and falls in older people. In this population, the requirements to produce explosive and rapid movements often occurs whilst simultaneously performing other attention-demanding cognitive or motor tasks, such as walking while talking or carrying an object. The primary aim of this study is to determine whether dual-task functional power training (DT-FPT) can reduce the rate of falls in community-dwelling older people. METHODS/DESIGN: The study design is an 18-month cluster randomised controlled trial in which 280 adults aged ≥65 years residing in retirement villages, who are at increased risk of falling, will be randomly allocated to: 1) an exercise programme involving DT-FPT, or 2) a usual care control group. The intervention is divided into 3 distinct phases: 6 months of supervised DT-FPT, a 6-month 'step down' maintenance programme, and a 6-month follow-up. The primary outcome will be the number of falls after 6, 12 and 18 months. Secondary outcomes will include: lower extremity muscle power and strength, grip strength, functional assessments of gait, reaction time and dynamic balance under single- and dual-task conditions, activities of daily living, quality of life, cognitive function and falls-related self-efficacy. We will also evaluate the cost-effectiveness of the programme for preventing falls. DISCUSSION: The study offers a novel approach that may guide the development and implementation of future community-based falls prevention programmes that specifically focus on optimising muscle power and dual-task performance to reduce falls risk under 'real life' conditions in older adults. In addition, the 'step down' programme will provide new information about the efficacy of a less intensive maintenance programme for reducing the risk of falls over an extended period. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613001161718 . Date registered 23 October 2013.


Assuntos
Acidentes por Quedas/prevenção & controle , Terapia por Exercício , Treinamento de Força/métodos , Atividades Cotidianas , Idoso , Protocolos Clínicos , Análise Custo-Benefício , Terapia por Exercício/economia , Humanos , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Qualidade de Vida , Projetos de Pesquisa
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