Effect of alternating postures on cognitive performance for healthy people performing sedentary work

Abstract

Prolonged sitting is a risk factor for several diseases and the prevalence of worksite-based interventions such as sit-to-stand workstations is increasing. Although their impact on sedentary behaviour has been regularly investigated, the effect of working in alternating body postures on cognitive performance is unclear. To address this uncertainty, 45 students participated in a two-arm, randomised controlled cross-over trial under laboratory conditions. Subjects executed validated cognitive tests (working speed, reaction time, concentration performance) either in sitting or alternating working postures on two separate days (ClinicalTrials.gov Identifier: NCT02863731). MANOVA results showed no significant difference in cognitive performance between trials executed in alternating, standing or sitting postures. Perceived workload did not differ between sitting and alternating days. Repeated measures ANOVA revealed significant learning effects regarding concentration performance and working speed for both days. These results suggest that working posture did not affect cognitive performance in the short term. Practitioner Summary: Prior reports indicated health-related benefits based on alternated (sit/stand) body postures. Nevertheless, their effect on cognitive performance is unknown. This randomised controlled trial showed that working in alternating body postures did not influence reaction time, concentration performance, working speed or workload perception in the short term.

Medium-term effects of a two-desk sit/stand workstation on cognitive performance and workload for healthy people performing sedentary work: a secondary analysis of a randomised controlled trial

“…keyboard distances, screen heights, screen angles) were adjusted by the study leader according to ergonomic recommendations (e.g. elbow height for the desks, screen heights for standing (15-45 ) or sitting (20-50 ) postures) prior to the measurments (Schwartz et al 2017). Participants' personal preferences were considered as long as those preferences did not markedly deviate from the aforementioned starting recommendations.…”

“…To reduce practice effects biases for cognitive tests, the first tests within the first battery of each measuring day were excluded from statistical analysis. Identically to our initial, short-term study (Schwartz et al 2017), data preparation and Stroop-test outlier elimination (values that differed by more than 3 standard deviations from a subject's mean) were performed using MATLAB to reduce errors due to occasional violations of the protocol (e.g. asking the investigator a question mid-test and thereby missing their cue).…”

“…We believed that such a reduction in sitting time would result in increased physical activity and provoke a subsequent reduction in mental fatigue that would lead to increased execution of functions, attention, concentration and memory (Loprinzi et al 2013;Colcombe and Kramer 2003;Ratey and Loehr 2011;Hillman, Kamijo, and Scudder 2011). It was expected that medium-term use of sit/stand workstations would show improvements in cognitive performance where short-term use of these workstations had not (Karakolis, Barrett, and Callaghan 2016;Schwartz et al 2017). Overall, these results seem to contradict the suggestion that sit-to-stand workstations positively influence mental fatigue (Wennberg et al 2016), at least insofar as improved cognitive performance is concerned.…”

“…Despite numerous studies of standing and sit/stand workstations, the effect of sit-to-stand transitions and sitting time reduction on cognitive performance has rarely been investigated. Currently, there are only a few studies that quantify the effects of sit-to-stand transitions and those studies are limited to short-term effects (Karakolis, Barrett, and Callaghan 2016;Schwartz et al 2017). Further, to our knowledge, besides a small number of studies investigating productivity (Garrett et al 2016), no randomised controlled trial determining the medium-term effect of a sit/stand workstation on cognitive parameters exist.…”

“…In summary, although physiological alterations caused by sit/stand workstation usage have been investigated (Gallagher, Campbell, and Callaghan 2014;Peddie et al 2013;Healy et al 2011), their effect on cognitive performanceespecially for the medium and long-term useis unclear. Hence, based on previously reported short-term findings (Schwartz et al 2017), the primary aim of this study was to report the mediumterm effect (i.e. effects after 23 weeks) of a two-desk sit/ stand workstation on typically office work related cognitive performance parameters (i.e.…”