Cognitive and skill performance of individuals at sitting versus standing workstations: a quasi-experimental study

Circadian Disruption in Civilian Airline Pilots

INTRODUCTION: Most airline pilots reported having suffered from sleep disorders and fatigue due to circadian disruption, a potential risk to flight safety. This study attempted to uncover the actual scenario of circadian disruption and working load status among airline pilots.METHODS: In study 1, 21 pilots were invited to participate in a 14-d sleep monitoring and a dual 2-back test to monitor their sleep patterns and cognitive function level. To provide an in-depth view, data from scheduled flights, including 567 airline pilots, was analyzed in Study 2. The present study used cluster analysis to reflect the distribution of the flight scheduling characteristics, including working time and actual working hours. A simulation model was then developed to predict the pilots' 1-mo sleep-wake pattern.RESULTS: The results indicated that sleep problems were prevalent in this population, especially the night before an earlier morning shift. Regarding the cognitive test, they scored the lowest on earlier morning shifts compared with daytime and evening shifts. It was found that over 70% of the flight schedules can lead to circadian disruption, and 47.44% of the pilots worked under high-load status.DISCUSSION: Airline pilots inevitably work irregular hours and the current policies for coping with circadian disruption seem inefficient. This study thus calls for urgency in improving scheduling and fatigue management systems from the circadian rhythm perspective.Yang SX, Cheng S, Sun Y, Tang X, Huang Z. Circadian disruption in civilian airline pilots. Aerosp Med Hum Perform. 2024; 95(7):381-389.

Stand up to better pay attention, sit down to better subtract: a new perspective on the advantage of cognitive-motor interactions

The Stroop task and subtraction rely on the different cognitive processes and cerebral regions, but both these cognitive functions interact with posture. The study of cognitive-motor interactions falls under the concept of sharing resources, implying that resources for processing are limited. Researchers try to understand this interaction by constructing dual task (DT) paradigms. None have investigated the Stroop and subtraction tasks in three inherently simple postures in two groups of young adults. This study aimed to test whether a given posture benefits a given cognitive function when cognitive and postural tasks are not overly demanding and are underpinned by common cerebral structures. This study presents the results of 60 healthy young adults performing a subtraction task in three postures (sitting, standing, and walking) and 57 healthy young adults performing the Stroop task in the same three postures. Our results showed that performance at the Stroop task, in terms of number of correct answers and interference, are better while standing or even walking compared to sitting while subtraction is better sitting compared to standing and walking. Moreover, static postural parameters did not vary when in DT compared to single task. This means that there was no additional cost on posture when achieving the cognitive activity simultaneously. The absence of impact of the DT on postural parameters in static postures and the changes in the gait pace when walking suggest that cognitive tasks can be achieved in various postures, without being too costly on posture.

Cardiac autonomic profile, perceived stress and environmental comfort in healthy employees during remote and in-office work

Remote work (REMOTE) causes an overlap between working and domestic demands. The study of the cardiac autonomic profile (CAP) by means of heart rate variability (HRV) provides information about the impact of REMOTE on workers' health. The primary aim was to determine whether CAP, self-perceived stress, environmental and workstation comfort are modified during REMOTE. The secondary aim was to explore how these indices are influenced by individual and environmental work-related factors. Fifty healthy office employees alternating REMOTE and in-office (OFFICE) working were enrolled, rated self-perceived stress, environmental and workstation comfort using a visual analogue scale and performed a 24-h electrocardiogram during REMOTE and OFFICE. Stress was lower (5.6 ± 2.2 vs. 6.4 ± 1.8), environmental comfort higher (7.7 ± 1.9 vs. 7.0 ± 1.5), and the workstation comfort poorer (6.2 ± 1.8 vs. 7.5 ± 1.2) during REMOTE. CAP was similar during REMOTE and OFFICE. CAP was influenced by some work-related factors, including the presence of offspring, absence of a dedicated workspace during REMOTE and number of working hours. All these variables determined a decreased vagal modulation. The working setting seems to impact the levels of perceived stress and comfort, but not the CAP. However, individual and environmental work-related factors reduce cardiac vagal modulation during REMOTE, potentially increasing the risk of developing cardiovascular diseases.

Does Standing Up Enhance Performance on the Stroop Task in Healthy Young Adults? A Systematic Review and Meta-Analysis

Understanding the changes in cognitive processing that accompany changes in posture can expand our understanding of embodied cognition and open new avenues for applications in (neuro)ergonomics. Recent studies have challenged the question of whether standing up alters cognitive performance. An electronic database search for randomized controlled trials was performed using Academic Search Complete, CINAHL Ultimate, MEDLINE, PubMed, and Web of Science following PRISMA guidelines, PICOS framework, and standard quality assessment criteria (SQAC). We pooled data from a total of 603 healthy young adults for incongruent and 578 for congruent stimuli and Stroop effect (mean age = 24 years). Using random-effects results, no difference was found between sitting and standing for the Stroop effect (Hedges' g = 0.13, 95% CI = -0.04 to 0.29, p = 0.134), even when comparing congruent (Hedges' g = 0.10; 95% CI: -0.132 to 0.339; Z = 0.86; p = 0.389) and incongruent (Hedges' g = 0.18; 95% CI: -0.072 to 0.422; Z = 1.39; p = 0.164) stimuli separately. Importantly, these results imply that changing from a seated to a standing posture in healthy young adults is unlikely to have detrimental effects on selective attention and cognitive control. To gain a full understanding of this phenomenon, further research should examine this effect in a population of healthy older adults, as well as in a population with pathology.

Benefits associated with the standing position during visual search tasks

The literature on postural control highlights that task performance should be worse in challenging dual tasks than in a single task, because the brain has limited attentional resources. Instead, in the context of visual tasks, we assumed that (i) performance in a visual search task should be better when standing than when sitting and (ii) when standing, postural control should be better when searching than performing the control task. 32 and 16 young adults participated in studies 1 and 2, respectively. They performed three visual tasks (searching to locate targets, free-viewing and fixating a stationary cross) displayed in small images (visual angle: 22°) either when standing or when sitting. Task performance, eye, head, upper back, lower back and center of pressure displacements were recorded. In both studies, task performance in searching was as good (and clearly not worse) when standing as when sitting. Sway magnitude was smaller during the search task (vs. other tasks) when standing but not when sitting. Hence, only when standing, postural control was adapted to perform the challenging search task. When exploring images, and especially so in the search task, participants rotated their head instead of their eyes as if they used an eye-centered strategy. Remarkably in Study 2, head rotation was greater when sitting than when standing. Overall, we consider that variability in postural control was not detrimental but instead useful to facilitate visual task performance. When sitting, this variability may be lacking, thus requiring compensatory movements.

Effects of mento-physical exercises on mental fatigue of shift work

Objectives. This study aims to investigate whether mento-physical exercises can decrease mental fatigue during shift work. Methods. Research subjects including the control room staff of an urban train system were chosen randomly, for whom mental fatigue was assessed before and after rest breaks for control and experimental groups. A new protocol was applied in the experimental group, including breathing exercises, isometric and isotonic exercises, and progressive relaxation during the inter-shift break. A designed questionnaire and the Stroop test were used to evaluate fatigue and the reaction time, respectively. Results. Pre and post-test results showed that mental, visual and physical fatigue and reaction time decreased by 14.48, 49.22, 26.85 and 8.35% in the control group and 36.42, 48.48, 76.37 and 20.56% in the experimental group, respectively. Conclusions. At the 5% α level, Student's t test showed that mento-physical exercises effectively decreased mental and physical fatigue as well as reaction time in the experimental group compared to the control group.