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1.
J Occup Environ Med ; 62(2): 145-148, 2020 Feb.
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.

2.
Appl Ergon ; 82: 102942, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479838

RESUMO

Sleep inertia, the state of reduced alertness upon waking, can negatively impact on-call workers. Anticipation of a stressful task on sleep inertia, while on-call was investigated. Young, healthy males (n = 23) spent an adaptation, control and two counterbalanced on-call nights in the laboratory. When on-call, participants were told they would be woken to a high or low stress task. Participants were not woken during the night, instead were given a 2300-0700 sleep opportunity. Participants slept ∼7.5-h in all conditions. Upon waking, sleep inertia was quantified using the Karolinska Sleepiness Scale and Psychomotor Vigilance and Spatial Configuration Tasks, administered at 15-min intervals. Compared to control, participants felt sleepier post waking when on-call and sleepiest in the low stress compared to the high stress condition (p < .001). Spatial performance was faster when on-call compared to control (p < .001). Findings suggest that anticipating a high-stress task when on-call, does not impact sleep inertia severity.

3.
J Sports Sci ; 37(23): 2691-2701, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31526108

RESUMO

This study investigated effects of total sleep deprivation on self-paced endurance performance, and heart rate (HR) indices of athletes' "readiness to perform". Endurance athletes (n = 13) completed a crossover experiment comprising a normal sleep (NS) and sleep deprivation (SD) condition. Each required completion of an endurance time-trial (TT) on consecutive days (D1, D2) separated by normal sleep or total sleep deprivation. Finishing time, perceived exertion (RPE), mood, psychomotor vigilance (PVT), and HR responses were assessed. Time on D2 of SD was 10% slower than D2 of NS (64 ± 7 vs 59 ± 4 min, P < 0.01), and 11% slower than D1 of SD (58 ± 5 min, P < 0.01). Subjective to objective (RPE:mean HR) intensity ratio was higher on D2 of SD compared with D2 of NS and D1 of SD (P < 0.01). Mood disturbance and PVT mean response time increased on D2 of SD compared with D2 of NS and D1 of SD. Anaerobic threshold and change in TT time were correlated (R = -0.73, P < 0.01). Sleep helps to optimise endurance performance. Subjective to objective intensity ratios appear sensitive to effects of sleep on athletes' readiness. Research examining more subtle sleep manipulation is required.


Assuntos
Ciclismo/fisiologia , Frequência Cardíaca/fisiologia , Resistência Física/fisiologia , Privação do Sono/fisiopatologia , Actigrafia/instrumentação , Adulto , Afeto/fisiologia , Ciclismo/psicologia , Estudos Cross-Over , Teste de Esforço , Humanos , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia , Tempo de Reação/fisiologia , Dispositivos Eletrônicos Vestíveis
4.
Psychoneuroendocrinology ; 109: 104406, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31472434

RESUMO

OBJECTIVE: This study had two specific objectives, 1) to investigate the impact of being on-call on overnight heart rate variability during sleep and; 2) to examine whether being on-call overnight impacted next-day salivary cortisol concentrations. METHODS: Data are reported from three within-subject laboratory studies (n = 24 in each study) that assessed varying on-call conditions. Healthy male participants (n = 72 total) completed a four-night laboratory protocol, comprising an adaptation night, a control night, and two counterbalanced on-call nights with varying on-call conditions. These on-call conditions were designed to determine the impact of, Study 1: the likelihood of receiving a call (definitely, maybe), Study 2: task stress (high-stress, low-stress), and Study 3: chance of missing the alarm (high-chance, low-chance), on measures of physiological stress. Overnight heart rate variability (HRV) (during sleep) was measured using two-lead electrocardiography, and time- and frequency-domain variables were analysed. Saliva samples were collected at 15-min time intervals from 0700-0800 h to determine cortisol awakening response outcomes and at four daily time points (0930 h, 1230 h, 1430 h, and 1730 h) to assess diurnal cortisol profiles. RESULTS: There were few differences in HRV measures during sleep across all three studies. The only exception was in Study 1 where the standard deviation of the time interval between consecutive heartbeats and the root mean square of consecutive differences between heartbeats were lower across all sleep stages in the definitely condition, when compared to control. Across all three studies, being on-call overnight also had little impact on next-day cortisol awakening response (CAR), with the exception of Study 2 where the 1) CAR area under the curve with respect to increase was blunted in the high-stress condition, compared to the control and low-stress conditions and, 2) CAR reactivity was higher in low-stress condition, compared with the high-stress condition. In Study 1, diurnal cortisol area under the curve with respect to ground was lower in the on-call conditions (definitely and maybe) when compared to control. There were no differences in diurnal cortisol measures in Study 3. CONCLUSION: This is the first study to investigate how different aspects of being on-call affect physiological stress responses. Overall, relatively little differences in measures of overnight heart rate variability and next-day cortisol response were recorded in all three studies. Further research utilising real on-call work tasks, not just on-call expectations (as in the current study) will help determine the impact of on-call work on the physiological stress response.

5.
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.

6.
Med Sci Sports Exerc ; 51(12): 2516-2523, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31246714

RESUMO

PURPOSE: The cumulative influence of sleep time on endurance performance remains unclear. This study examined the effects of three consecutive nights of both sleep extension (SE) and sleep restriction (SR) on endurance cycling performance. METHODS: Endurance cyclists/triathletes (n = 9) completed a counterbalanced crossover experiment with three conditions: SR, normal sleep (NS), and SE. Each condition comprised seven days/nights of data collection (-2, -1, D1, D2, D3, D4, and +1). Sleep was monitored using actigraphy throughout. Participants completed testing sessions on days D1-D4 that included an endurance time-trial (TT), mood, and psychomotor vigilance assessment. Perceived exertion (RPE) was monitored throughout each TT. Participants slept habitually before D1; however, time in bed was reduced by 30% (SR), remained normal (NS), or extended by 30% (SE) on nights D1, D2, and D3. Data were analyzed using generalized estimating equations. RESULTS: On nights D1, D2, and D3, total sleep time was longer (P < 0.001) in the SE condition (8.6 ± 1.0, 8.3 ± 0.6, and 8.2 ± 0.6 h, respectively) and shorter (P < 0.001) in the SR condition (4.7 ± 0.8, 4.8 ± 0.8, and 4.9 ± 0.4 h) compared with NS (7.1 ± 0.8, 6.5 ± 1.0, and 6.9 ± 0.7 h). Compared with NS, TT performance was slower (P < 0.02) on D3 of SR (58.8 ± 2.5 vs 60.4 ± 3.7 min) and faster (P < 0.02) on D4 of SE (58.7 ± 3.4 vs 56.8 ± 3.1 min). RPE was not different between or within conditions. Compared with NS, mood disturbance was higher, and psychomotor vigilance impaired, after SR. Compared with NS, psychomotor vigilance improved after SE. CONCLUSION: Sleep extension for three nights led to better maintenance of endurance performance compared with normal and restricted sleep. Sleep restriction impaired performance. Cumulative sleep time affects performance by altering the perceived exertion of a given exercise intensity. Endurance athletes should sleep >8 h per night to optimize performance.

7.
Sports Med ; 49(11): 1637-1650, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31190324

RESUMO

Resistance training is essential for health and performance and confers many benefits such as increasing skeletal muscle mass, increasing strength and power output, and improving metabolic health. Resistance training is a major component of the physical activity guidelines, yet research in female populations is limited. Recent increases in the promotion of, and the participation by, females in sport and exercise, highlight the need for an increase in understanding of evidence-based best practice exercise prescription for females. The aim of this review is to provide an overview of the current research regarding resistance training performance and skeletal muscle adaptation in females, with a focus on the hormonal variables that may influence resistance training outcomes. Findings suggest that the menstrual cycle phase may impact strength, but not skeletal muscle protein metabolism. In comparison, oral contraception use in females may reduce skeletal muscle protein synthesis, but not strength outcomes, when compared to non-users. Future research should investigate the role of resistance training in the maintenance of skeletal muscle protein metabolism during pregnancy, menopause and in athletes experiencing relative energy deficiency in sport. The review concludes with recommendations for researchers to assist them in the inclusion of female participants in resistance training research specifically, with commentary on the most appropriate methods of controlling for, or understanding the implications of, hormonal fluctuations. For practitioners, the current evidence suggests possible resistance training practices that could optimise performance outcomes in females, although further research is warranted.

8.
Stress ; 22(4): 436-445, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30935351

RESUMO

Working on-call with a night call resulted in a depressed (lower) cortisol awakening response (CAR) peak and post-awakening cortisol area under the curve with respect to ground (AUCG) the following day compared to when off-call. This may be due to exposure to noise, physical exertion, and stressful events during night callouts. There was no anticipatory effect to working on-call in any of the cortisol measures examined. This study, of male fire and emergency service workers who operate on-call from home, had two aims: (1) examine CAR and diurnal cortisol profile following a night on-call with a call, on-call without a call, and off-call; and, (2) explore whether there is an anticipatory effect of working on-call from home on diurnal cortisol profiles. Participants wore activity monitors, completed sleep and work diaries and collected seven saliva samples a day (0 min, 30 min, 60 min, 3 h, 6 h, 9 h, and 12 h after final awakening) for one week. CAR peak, reactivity and area under the curve with respect to increase (AUCI), post-awakening cortisol AUCG, diurnal cortisol slope and AUCG, and mean 12-h cortisol concentrations were calculated. The final analysis included 26 participants for Aim 1 (22 off-call nights, 68 nights on-call without a call, and 20 nights on-call with a call) and 14 participants for Aim 2 (25 days leading up to a night off-call and 92 days leading up to a night on-call). Generalized estimating equations models were constructed for each variable of interest. Aim 1: CAR peak and post-awakening cortisol AUCG were 8.2 ± 3.4 nmol/L and 5.7 ± 2.4 units lower, respectively, following a night on-call with a call compared to an off-call night. Aim 2: the day before a night on-call was not a significant predictor in any model. The lower CAR peak and post-awakening cortisol AUCG following a night on-call with a call compared to following an off-call night may be due to exposure to noise, physical exertion, and stressful events during night callouts. The lack of difference between the day before a night on-call and the day before an off-call night suggests there may not be an anticipatory effect on cortisol when on-call from home.


Assuntos
Hidrocortisona/metabolismo , Estresse Psicológico/fisiopatologia , Adulto , Ritmo Circadiano/fisiologia , Depressão , Feminino , Humanos , Hidrocortisona/análise , Masculino , Pessoa de Meia-Idade , Saliva/metabolismo , Vigília/fisiologia
9.
Appl Ergon ; 77: 9-15, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30832782

RESUMO

The effects on dehydration and cognitive performance from heat and/or physical activity are well established in the laboratory, although have not yet been studied for personnel working in occupations such as wildland firefighting regularly exposed to these types of conditions. This study aimed to investigate the effects of temperature and dehydration on seventy-three volunteer firefighters (35.7 ±â€¯13.7 years, mean ±â€¯standard deviation) during a simulation of wildfire suppression under either control or hot (18-20; or 33-35 °C) temperature conditions. Results showed cognitive performance on the psychomotor vigilance task declined when participants were dehydrated in the heat and Stroop task performance was impaired when dehydrated late in the afternoon. Firefighters may be at risk of deteriorations in simple cognitive functions in the heat whilst dehydrated, although may also experience impairments in complex cognitive functions if dehydrated late in the day, irrespective of the environmental temperature.


Assuntos
Desidratação/psicologia , Bombeiros/psicologia , Temperatura Alta/efeitos adversos , Doenças Profissionais/psicologia , Adulto , Cognição , Simulação por Computador , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor , Incêndios Florestais , Desempenho Profissional
10.
Chronobiol Int ; 35(6): 827-837, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29750617

RESUMO

BACKGROUND: The unpredictable, "on-call" component of the emergency services (ES) may be difficult to navigate in the context of domestic and work responsibilities, and especially difficult for women, given they tend to take on a greater household burden than do men. Our aim was to understand women's experiences in the ES, particularly the impact of being on-call and related coping strategies. METHODS: Twenty-four women were recruited from two ES agencies in Australia. Participation involved a brief questionnaire and a 45-60-min interview. Interviews were recorded, and audio files were transcribed before analysis using nVIVO software. RESULTS: Interview data identified two major themes: impact and management. Women talked about the impact of on-call for themselves (e.g. disturbed? sleep, fatigue and the relentlessness of the role) but also discussed the, largely negative, impact for their family/household. In terms of management, support (family, social and work) and planning and preparation were identified as important in helping women manage their multiple roles in the context of on-call unpredictability. CONCLUSION: The negative impacts of on-call work on women's sleep supports existing quantitative and qualitative data in the broader on-call area. For those women with children, managing their care presents one of the biggest challenges to being able to manage the on-call component of their work. Future research should to focus on quantifying the impact of on-call for both men and women, particularly the "relentlessness" of the work identified in this study and whether this toll changes based on other factors such as experience, role or gender.


Assuntos
Adaptação Psicológica/fisiologia , Ritmo Circadiano/fisiologia , Serviços Médicos de Emergência , Descanso/fisiologia , Adulto , Austrália , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Socioeconômicos , Adulto Jovem
11.
Int Arch Occup Environ Health ; 91(5): 601-611, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29623407

RESUMO

PURPOSE: To examine the effects of sleep restriction on firefighters' physical task performance, physical activity, and physiological and perceived exertion during simulated hot wildfire conditions. METHODS: 31 firefighters were randomly allocated to either the hot (n = 18, HOT; 33 °C, 8-h sleep opportunity) or hot and sleep restricted (n = 13, HOT + SR; 33 °C, 4-h sleep opportunity) condition. Intermittent, self-paced work circuits of six firefighting tasks were performed for 3 days. Firefighters self-reported ratings of perceived exertion. Heart rate, core temperature, and physical activity were measured continuously. Fluids were consumed ad libitum, and all food and fluids consumed were recorded. Urine volume and urine specific gravity (USG) were analysed and sleep was assessed using polysomnography (PSG). RESULTS: There were no differences between the HOT and HOT + SR groups in firefighters' physical task performance, heart rate, core temperature, USG, or fluid intake. Ratings of perceived exertion were higher (p < 0.05) in the HOT + SR group for two of the six firefighting tasks. The HOT group spent approximately 7 min more undertaking moderate physical activity throughout the 2-h work circuits compared to the HOT + SR group. CONCLUSION: Two nights of sleep restriction did not influence firefighters' physical task performance or physiological responses during 3 days of simulated wildfire suppression. Further research is needed to explore firefighters' pacing strategies during real wildfire suppression.


Assuntos
Bombeiros , Temperatura Alta , Privação do Sono/fisiopatologia , Desempenho Profissional , Adulto , Austrália , Exercício/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória , Sono/fisiologia , Análise e Desempenho de Tarefas , Adulto Jovem
12.
Appl Ergon ; 68: 197-203, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29409635

RESUMO

Many police organisations incorporate specialist policing roles where incumbents are tasked with providing operational response capabilities above and beyond the general duties policing role. The current research utilised subjective job task analysis methods to identify and characterise the physically demanding, frequently occurring, and operationally important tasks, as well as the dominant fitness component for each task, inherent to specialist policing roles in an Australian policing organisation. This was achieved through engagement with subject matter experts and online survey responses from specialist police incumbents. In total, 11 criterion tasks were identified, which covered a range of physical capacities including muscular strength, muscular endurance, and aerobic power. The most physically demanding tasks included those with an arrest component, requiring high muscular strength and power capacities. Having identified the criterion tasks, three operational scenarios were constructed, which incorporated each of the 11 tasks in different operational contexts. The criterion tasks and composite scenarios will allow practitioners within specialised police units to develop evidence-based strategies, including physical selection procedures and physical training programs, specific to the demands of their work.


Assuntos
Força Muscular/fisiologia , Resistência Física/fisiologia , Polícia , Análise e Desempenho de Tarefas , Trabalho/fisiologia , Adulto , Austrália , Feminino , Humanos , Masculino , Avaliação da Capacidade de Trabalho
13.
J Sci Med Sport ; 21(9): 959-968, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29422383

RESUMO

OBJECTIVES: Inadequate sleep (e.g., an insufficient duration of sleep per night) can reduce physical performance and has been linked to adverse metabolic health outcomes. Resistance exercise is an effective means to maintain and improve physical capacity and metabolic health, however, the outcomes for populations who may perform resistance exercise during periods of inadequate sleep are unknown. The primary aim of this systematic review was to evaluate the effect of sleep deprivation (i.e. no sleep) and sleep restriction (i.e. a reduced sleep duration) on resistance exercise performance. A secondary aim was to explore the effects on hormonal indicators or markers of muscle protein metabolism. METHODS: A systematic search of five electronic databases was conducted with terms related to three combined concepts: inadequate sleep; resistance exercise; performance and physiological outcomes. Study quality and biases were assessed using the Effective Public Health Practice Project quality assessment tool. RESULTS: Seventeen studies met the inclusion criteria and were rated as 'moderate' or 'weak' for global quality. Sleep deprivation had little effect on muscle strength during resistance exercise. In contrast, consecutive nights of sleep restriction could reduce the force output of multi-joint, but not single-joint movements. Results were conflicting regarding hormonal responses to resistance training. CONCLUSION: Inadequate sleep impairs maximal muscle strength in compound movements when performed without specific interventions designed to increase motivation. Strategies to assist groups facing inadequate sleep to effectively perform resistance training may include supplementing their motivation by training in groups or ingesting caffeine; or training prior to prolonged periods of wakefulness.


Assuntos
Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Treinamento de Resistência , Privação do Sono/fisiopatologia , Humanos , Sono
14.
Ergonomics ; 61(2): 265-272, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28738728

RESUMO

Search and rescue operations are necessary in locating, assisting and recovering individuals lost or in distress. In Australia, land-based search and rescue roles require a range of physically demanding tasks undertaken in dynamic and challenging environments. The aim of the current research was to identify and characterise the physically demanding tasks inherent to search and rescue operation personnel within Australia. These aims were met through a subjective job task analysis approach. In total, 11 criterion tasks were identified by personnel. These tasks were the most physically demanding, frequently occurring and operationally important tasks to these specialist roles. Muscular strength was the dominant fitness component for 7 of the 11 tasks. In addition to the discrete criterion tasks, an operational scenario was established. With the tasks and operational scenario identified, objective task analysis procedures can be undertaken so that practitioners can implement evidence-based strategies, such as physical selection procedures and task-based physical training programs, commensurate with the physical demands of search and rescue job roles. Practitioner Summary: The identification of physically demanding tasks amongst specialist emergency service roles predicates health and safety strategies which can be incorporated into organisations. Knowledge of physical task parameters allows employers to mitigate injury risk through the implementation of strategies modelled on the precise physical demands of the role.


Assuntos
Esforço Físico , Trabalho de Resgate , Análise e Desempenho de Tarefas , Voluntários , Adulto , Austrália , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular , Seleção de Pessoal , Aptidão Física , Inquéritos e Questionários
15.
Front Physiol ; 8: 815, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29114230

RESUMO

Background: The severity of wildland fires is increasing due to continually hotter and drier summers. Firefighters are required to make life altering decisions on the fireground, which requires analytical thinking, problem solving, and situational awareness. This study aimed to determine the effects of very hot (45°C; HOT) conditions on cognitive function following periods of simulated wildfire suppression work when compared to a temperate environment (18°C; CON). Methods: Ten male volunteer firefighters intermittently performed a simulated fireground task for 3 h in both the CON and HOT environments, with cognitive function tests (paired associates learning and spatial span) assessed at baseline (cog 1) and during the final 20-min of each hour (cog 2, 3, and 4). Reaction time was also assessed at cog 1 and cog 4. Pre- and post- body mass were recorded, and core and skin temperature were measured continuously throughout the protocol. Results: There were no differences between the CON and HOT trials for any of the cognitive assessments, regardless of complexity. While core temperature reached 38.7°C in the HOT (compared to only 37.5°C in the CON; p < 0.01), core temperature declined during the cognitive assessments in both conditions (at a rate of -0.15 ± 0.20°C·hr-1 and -0.63 ± 0.12°C·hr-1 in the HOT and CON trial respectively). Firefighters also maintained their pre-exercise body mass in both conditions, indicating euhydration. Conclusions: It is likely that this maintenance of euhydration and the relative drop in core temperature experienced between physical work bouts was responsible for the preservation of firefighters' cognitive function in the present study.

16.
J Sci Med Sport ; 20 Suppl 4: S104-S108, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28919496

RESUMO

OBJECTIVES: This investigation assessed the accuracy of error of the Pandolf load carriage energy expenditure equation when simulating contemporary military conditions (load distribution, external load and walking speed). DESIGN: Within-participant design. METHODS: Sixteen male participants completed 10 trials comprised of five walking speeds (2.5, 3.5, 4.5, 5.5 and 6.5km·h-1) and two external loads (22.7 and 38.4kg). RESULTS: The Pandolf equation demonstrated poor predictive precision, with a mean bias of 124.9W and -48.7 to 298.5W 95% limits of agreement. Furthermore, the Pandolf equation systematically under-predicted metabolic rate (p<0.05) across the 10 speed-load combinations. Predicted metabolic rate error ranged from 12-33% across all conditions with the 'moderate' walking speeds (i.e. 4.5-5.5km·h-1) yielding less prediction error (12-17%) when compared to the slower and faster walking speeds (21-33%). CONCLUSIONS: Factors such as mechanical efficiency and load distribution contribute to the impaired predictive accuracy. The authors suggest the Pandolf equation should be applied to military load carriage with caution.


Assuntos
Metabolismo Energético/fisiologia , Militares , Esforço Físico/fisiologia , Suporte de Carga/fisiologia , Adulto , Análise de Variância , Teste de Esforço/métodos , Humanos , Masculino , Reprodutibilidade dos Testes , Caminhada/fisiologia
17.
Endocr Connect ; 6(8): 637-646, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28928228

RESUMO

The effect of working on-call from home on the sympatho-adrenal medullary system activity is currently unknown. This study had two aims, Aim 1: examine salivary alpha amylase awakening response (AAR) and diurnal salivary alpha amylase (sAA) profile in fire and emergency service workers who operate on-call from home following a night on-call with a call (NIGHT-CALL), a night on-call without a call (NO-CALL) and an off-call night (OFF-CALL), and Aim 2: explore whether there was an anticipatory effect of working on-call from home (ON) compared to when there was an off-call (OFF) on the diurnal sAA profile. Participants wore activity monitors, completed sleep and work diaries and collected seven saliva samples a day for one week. AAR area under the curve with respect to ground (AUCG), AAR area under the curve with respect to increase (AUCI), AAR reactivity, diurnal sAA slope, diurnal sAA AUCG and mean 12-h sAA concentrations were calculated. Separate generalised estimating equation models were constructed for each variable of interest for each aim. For Aim 1, there were no differences between NIGHT-CALL or NO-CALL and OFF-CALL for any response variable. For Aim 2, there was no difference between any response variable of interest when ON the following night compared to when OFF the following night (n = 14). These findings suggest that there is no effect of working on-call from home on sAA, but should be interpreted with caution, as overnight data were not collected. Future research, using overnight heart rate monitoring, could help confirm these findings.

18.
Int J Nurs Stud ; 73: 52-62, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28535398

RESUMO

BACKGROUND: Nurses' physical performance at work has implications both for nurses' occupational health and patient care. Although nurses are the largest healthcare workforce, are present 24-hours a day, and engage in many physically demanding tasks, nurses' occupational physical activity levels are poorly understood. OBJECTIVES: The aim of this systematic review was to examine nurses' occupational physical activity levels, and explore how nurses accumulate their physical activity during a shift. DESIGN: This narrative systematic review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Statement. DATA SOURCES: EBSCOHost (MEDLINE, CINAHL, Age Line, Academic Search Complete, Global Health, Health Business Centre, Health Policy Reference Centre, Health Source (Consumer and Nursing/Academic Edition) and SPORTDiscus), Embase, Informit, ProQuest Health and Medical, Science Direct, Scopus, and Web of Science databases. REVIEW METHODS: A systematic search of seven databases were completed to locate peer-reviewed journal articles documenting nurses' occupational physical activity levels from January 1990. Papers were included if they were original research papers; measured physical activity objectively and/or subjectively; reported nurses' occupational physical activity; and were published in English. Articles were excluded if nurses' data were not reported separately from other professional groups. Two researchers independently screened the articles, extracted data, and undertook the methodological quality assessments. RESULTS: Fifteen studies met the inclusion criteria. Nursing work predominantly comprised of light-intensity physical activity. In nine studies how nurses' accumulated occupational physical activity were documented and showed that the majority of a nurses' shift was spent standing or walking whilst completing direct patient care tasks. However, the definition of the nursing populations studied were often poorly reported, and few researchers reported the validity and the reliability of the measurement tools used. CONCLUSIONS: Nurses' occupational physical activity levels largely consist of light-intensity physical activity interspersed with moderate-intensity tasks. It is not known whether physical activity during one shift affects the activity levels in the following shift. This systematic review is the first step towards understanding the physical demands of nursing work, and how nurses' physical activity may impact workplace wellbeing and patient safety. LIMITATIONS: A meta-analysis was not possible due to the variability in how physical activity outcomes were presented. Several studies had heart rate outcomes that were converted, where possible, by the authors into physical activity outcomes. REGISTRATION: This systematic review is registered with PROSPERO; Registration number: CRD42016045427.


Assuntos
Exercício , Recursos Humanos de Enfermagem , Humanos
19.
Ann Work Expo Health ; 61(5): 600-603, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28383724

RESUMO

Objective: To examine firefighters' hormonal and immune markers during consecutive days of physical firefighting work performed in hot compared to mild ambient temperatures. Methods: Firefighters completed 3 days of simulated physical firefighting work in either hot (HOT condition; n = 19; 33°C) or mild temperature conditions (CON condition; n = 18; 19°C). Participants provided regular daily samples for the determination of salivary cortisol and plasma cytokine levels (IL-6, IL-8, IL-1ß, TNF-α, IL-4, and IL-10). Results: The HOT condition elicited higher IL-4 and a trend towards elevated afternoon and evening cortisol when compared to the CON trial. The HOT condition also produced lower levels of IL-1ß compared to the CON across time points and a decrease in IL-1ß between days of work. IL-6 increased across time points and between work days, but this finding was not different between mild and hot conditions. Immune-endocrine interactions revealed a rise in morning IL-6 that was related to elevated daily cortisol levels, independent of condition. Conclusion: Findings demonstrate the possibility that firefighters are able to regulate normal acute immune and hormonal responses to multiple days of simulated physical work in hot and mild ambient temperatures. Further research is necessary to determine if the responses continue under non-simulated conditions and in response to more extreme temperatures possible on the fire-ground.


Assuntos
Citocinas/sangue , Bombeiros , Temperatura Alta/efeitos adversos , Hidrocortisona/análise , Esforço Físico/fisiologia , Estresse Fisiológico/fisiologia , Adulto , Biomarcadores/análise , Humanos , Masculino , Saliva/química , Temperatura Ambiente
20.
Nutrients ; 9(3)2017 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-28282858

RESUMO

(1) Background: About one in four workers undertake shift rosters that fall outside the traditional 7 a.m.-6 p.m. scheduling. Shiftwork alters workers' exposure to natural and artificial light, sleep patterns, and feeding patterns. When compared to the rest of the working population, shiftworkers are at a greater risk of developing metabolic impairments over time. One fundamental component of metabolic health is skeletal muscle, the largest organ in the body. However, cause-and-effect relationships between shiftwork and skeletal muscle health have not been established; (2) Methods: A critical review of the literature was completed using online databases and reference lists; (3) Results: We propose a conceptual model drawing relationships between typical shiftwork consequences; altered light exposure, sleep patterns, and food and beverage consumption, and drivers of skeletal muscle health-protein intake, resistance training, and hormone release. At present, there is no study investigating the direct effect of shiftwork on skeletal muscle health. Instead, research findings showing that acute consequences of shiftwork negatively influence skeletal muscle homeostasis support the validity of our model; (4) Conclusion: Further research is required to test the potential relationships identified in our review, particularly in shiftwork populations. Part of this testing could include skeletal muscle specific interventions such as targeted protein intake and/or resistance-training.


Assuntos
Músculo Esquelético/fisiologia , Tolerância ao Trabalho Programado/fisiologia , Animais , Humanos , Metanálise como Assunto , Modelos Animais , Fatores de Risco , Sono/fisiologia , Inquéritos e Questionários
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