The energy expenditure benefits of reallocating sedentary time with physical activity: a systematic review and meta-analysis

Background: We compared direct and daily cumulative energy expenditure (EE) differences associated with reallocating sedentary time to physical activity in adults for meaningful EE changes. Methods: Peer-reviewed studies in PubMed, Medline, EMBASE, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews were searched from inception to March 2017. Randomized and non-randomized interventions with sedentary time and EE outcomes in adults were included. Study quality was assessed by the National Heart Lung and Blood Institute tool, and summarized using random-effects meta-analysis and meta-regression. Results: In total, 26 studies were reviewed, and 24 studies examined by meta-analysis. Reallocating 6-9 h of sedentary time to light-intensity physical activity (LIPA) (standardized mean difference [SMD], 2.501 ) had lower cumulative EE than 6-9 h of combined LIPA and moderate-vigorous intensity physical activity (LIPA and moderate-vigorous physical activity [MVPA]) (SMD, 5.218 ). Reallocating 1 h of MVPA resulted in greater cumulative EE than 3-5 h of LIPA and MVPA, but <6-9 h of LIPA and MVPA. Conclusions: Comparable EE can be achieved by different strategies, and promoting MVPA might be effective for those individuals where a combination of MVPA and LIPA is challenging