Do energy expenditure differences across work postures influence cognitive processing speed? A counter-balanced randomised cross-over trial

BACKGROUND: Anecdotal evidence links occupational sedentary behaviour, low energy expenditure (EE) and cognitive dysfunction. Nevertheless, EE across different work postures including active workstations remains unclear and its influence on cognitive processing speed is yet to be established. OBJECTIVE: We aimed to investigate differences in EE across various work postures and its influence on cognitive processing speed. METHODS: Sixteen desk-based employees performed simulated work tasks (typing, reading and cognitive tasks) in three different work positions (sitting, standing, and walking) in three different days. EE was measured for three days consecutively for 30-minutes in three simulated working postures using indirect calorimetry. Cognitive processing speed was assessed through computer-based choice reaction times during each work posture. The outcome variables of interest (EE, reaction times and accuracy) were compared between three work postures using repeated measures ANOVA and Pearson correlation. RESULTS: EE in walking posture was higher (5.57±0.45 Kcal) than sitting (1.07±0.12 Kcal) and standing (1.88±0.42 Kcal). Total EE was significantly higher in walking than standing (35.17±6.86 Kcal) and sitting postures (41.37±8.46 Kcal). We did not find any significant differences in cognitive processing speed between different work postures except within standing work condition (60.22±13.97 ms). Accuracy was found to be reduced in walking compared to sitting (0.76±0.83%) and standing (0.43±0.09%) but not reached significance. CONCLUSION: Although significant differences in EE were observed between work postures, walking or standing at work did not affect the cognitive processing speed.