This study was designed to examine the effects of ambient heat on firefighters’ physical task performance, and physiological and perceptual responses when sleep restricted during simulated wildfire conditions. Thirty firefighters were randomly allocated to the sleep restricted (n = 17, SR; 19 °C, 4-h sleep opportunity) or hot and sleep restricted (n = 13, HOT + SR; 33 °C, 4-h sleep opportunity) condition. Firefighters performed two days of simulated, intermittent, self-paced work circuits comprising six firefighting tasks. Heart rate, and core temperature were measured continuously. After each task, firefighters reported their rating of perceived exertion and thermal sensation. Effort sensation was also reported after each work circuit. Fluids were consumed ad libitum. Urine volume and urine specific gravity were analysed. Sleep was monitored using polysomnography. There were no differences between the SR and HOT + SR groups in firefighters’ physiological responses, hydration status, ratings of perceived exertion, motivation, and four of the six firefighting tasks (charged hose advance, rake, hose rolling, static hose hold). Black out hose and lateral repositioning were adversely affected in the HOT + SR group. Working in hot conditions did not appear to consistently impair firefighters work performance, physiology, and perceptual responses. Future research should determine whether such findings remain true when individual tasks are performed over longer durations. Full article

During school hours, children can sit for prolonged and unbroken periods of time. This study investigated the impact of an 8-month classroom-based intervention focusing on reducing and breaking-up sitting time on children’s cardio-metabolic risk factors (i.e., body mass index, waist circumference, blood pressure) and perceptions of musculoskeletal discomfort. Two Year-6 classes (24 students per class) in one primary school were assigned to either an intervention or control classroom. The intervention classroom was equipped with height-adjustable desks and the teacher was instructed in the delivery of pedagogical strategies to reduce and break-up sitting in class. The control classroom followed standard practice using traditional furniture. At baseline, and after 8-months, time spent sitting, standing, stepping, and sitting-bouts (occasions of continuous sitting) as well as the frequency of sit-to-stand transitions were obtained from activPAL inclinometers and the time spent in light-intensity physical activity was obtained from ActiGraph accelerometers. Demographics and musculoskeletal characteristics were obtained from a self-report survey. Hierarchical linear mixed models found that during class-time, children’s overall time spent sitting in long bouts (>10 min) were lower and the number of sit-to-stand transitions were higher in the intervention group compared to the control group, while no changes were observed for musculoskeletal pain/discomfort. No significant intervention effects were found for the anthropometrics measures and blood pressure. Height-adjustable desks and pedagogical strategies to reduce/break-up sitting can positively modify classroom sitting patterns in children. Longer interventions, larger and varied sample size may be needed to show health impacts; however, these desks did not increase musculoskeletal pain/discomfort. Full article

Little is currently known about the physical activity patterns of workers in physically demanding populations. The aims of this study were to (a) quantify firefighters’ physical activity and sedentary time within (2-h periods) and across planned burn shifts; and (b) examine whether firefighters’ activity levels during one shift or 2-h period was associated with their activity levels in the following shift or 2-h period. Thirty-four salaried firefighters (26 men, 8 women) wore an Actical accelerometer for 28 consecutive days. Time spent sedentary (SED) and in light- (LPA), moderate- (MPA) and vigorous-intensity physical activity (VPA) were derived using validated cut-points. Multilevel analyses (shift, participant) were conducted using generalised linear latent and mixed models. Firefighters spent the majority of a planned burn shift (average length 10.4 h) or 2-h period engaged in LPA (69% and 70%, respectively). No significant associations were observed between SED and physical activity levels between consecutive planned burned shifts or 2-h periods. The physical activity that a firefighter engaged in during one shift (or 2-h period) did not subsequently affect their physical activity levels in the subsequent shift (or 2-h period). Further research is needed to establish how workers in physically demanding populations are able to sustain their activity levels over long periods of time. Full article