Dose-response effects of periodic physical activity breaks on the chronic inflammatory risk associated with sedentary behavior in high- and upper-middle income countries: A systematic review and meta-analysis

Background and aims: Though moderate-vigorous physical activity (MVPA) is speculated to mitigate the inflammatory risk associated with sedentary behavior, only a fraction of the global population meets the recommended weekly dose of MVPA. More individuals indulge in bouted and sporadic light-intensity physical activity (LIPA) that occurs throughout the typical day. However, the anti-inflammatory effects of LIPA or MVPA breaks during prolonged sitting remains unclear. Methods: A systematic search was done on six peer-reviewed databases through January 27th, 2023. Two authors independently screened the citations for eligibility, and risk of bias and performed a meta-analysis. Results: The included studies originated from high and upper – middle income countries. Observational studies of SB interruptions with LIPA showed favourable effects on inflammatory mediators such as higher levels of adiponectin (odds ratio, OR = +0.14; p = 0.02). However, these findings are not supported by the experimental studies. Experimental studies reported non-significant increase in cytokines including IL-1β (standardised mean difference, SMD = 0.11 pg/ml; p = 0.29) and IL-6 (SMD = 0.19 pg/ml; p = 0.46) after interrupting sitting with LIPA breaks. But these LIPA breaks were found to reduce C-reactive protein (SMD = - 0.50 mg/dl; p = 0.85) and IL-8 levels (SMD = −0.08 pg/ml; p = 0.34) but did not reach statistical significance. Conclusion: Interrupting prolonged sitting time with LIPA breaks shows promise for preventing the inflammatory effects associated with prolonged bouts of daily sitting, though the evidence remains in infancy and limited to high- and upper-middle income countries.