Effects of Disrupting Prolonged Sitting With Different Physical Activity Protocols on Metabolic Risk Factors in Sedentary Adults

Great controversy exists with respect to the optimal or the minimum volume, intensity, and frequency of physical activity capable of attenuating the hazards of prolonged sitting on the metabolic profile. Thus, our study aims to comprehensively investigate the effects of disrupting prolonged sitting with different physical activity protocols on metabolic risk factors in sedentary males. Ten sedentary males will take part in this randomized cross-over trial consisting of four 27-h conditions. All conditions will be identical except for the physical activity: prolonged sitting intervention (SIT) participants will sit continuously for 9 hours; prolonged sitting+interval standing intervention (STAND), participants will stand for 15 min every 30 minutes (total 270 min) during the 9 hours of sitting; prolonged sitting+moderate-intensity exercise bout (MVPA) participants will perform a 30-min moderate-intensity exercise bout on a treadmill (energy-matched to STAND), after which they will sit for the remaining time; and prolonged sitting+moderate-intensity exercise bout +interval standing intervention (MVPA-STAND), participants will perform a 30-min moderate-intensity exercise bout on a treadmill (energy-matched to STAND), after which they will stand for 15 min every 30 minutes (total 240 min) during the remaining 8 hours of sitting. Blood glucose, insulin, lipids and cytokines will be determined. The investigators expect that disrupting prolonged sitting with intermittent standing and a moderate-exercise bout will positively affect the metabolic profile of the participants. Furthermore, we will investigate if combined, these strategies will have an additive effect.