Sitting to standing postural changes: energy expenditure and a possible mechanism to alleviate sedentary behavior

Background and aims
Sedentary lifestyles have recently been identified as potential mechanism for obesity and associated metabolic diseases linked to ill health. The aim of this study was to investigate the effects of standing and sitting–standing positional changes on energy cost and consequently interrupting sedentary sitting time while working.

Methods
A total of 26 healthy male volunteers performed normal typing and editing work for 100 min under three conditions. The conditions included sustained sitting, sustained standing, and sitting–standing alternation every 20 min using a sit–stand desk. Respiratory parameters measured included minute ventilation (VE), oxygen consumption (VO2), and energy expenditure (EE). Measurements were recorded using a calibrated Cosmed K4b2 portable gas analysis system.

Results
The mean value for VE was the highest in the standing position (VE = 13.33 ± 0.71), followed by sitting–standing alternation (VE = 12.04 ± 0.62). Both were significantly different from sitting (VE = 10.59 ± 0.69). The maximum VE and EE for standing (VE = 14.81 ± 0.43 and EE = 1.84 ± 0.10) and sitting–standing alternation (VE = 14.80 ± 0.40 and EE = 1.93 ± 0.08) were significantly higher than that of sitting (VE = 12.15 ± 0.42 and EE = 1.67 ± 0.07). No significant differences were observed in the mean VO2 among the three conditions. However, the maximum VO2 for both standing (VO2 = 5.40 ± 0.20) and sitting–standing alternation (VO2 = 5.14 ± 0.17) had shown to be significantly higher than sitting (VO2 = 4.50 ± 0.18). There were no significant differences observed in the mean EE levels between sitting (EE = 1.43 ± 0.07) and sitting–standing alternation (EE = 1.55 ± 0.08). However, the mean EE while standing (EE = 1.62 ± 0.09) significantly increased compared to sitting.

Conclusions
The findings of this study indicate that sitting–standing alternations may be implemented as an effective intervention to interrupt prolonged sitting while working.