- Cardiovascular disease (CVD) is the leading cause of death worldwide. CVD survivors often experience a low quality of life and high cost of medical treatment and rehabilitation, which may cause great psychological and financial burden on patients and their families. Therefore, effective early interventions in the modifiable risk factors for CVD is of great significance to clinical and public health practice. Postprandial hyperglycemia and hyperinsulinemia are considered as independent predictors for the development of future CVD, and thus effective interventions to lower postprandial hyperglycemia and hyperinsulinemia could be important for CVD prevention.
- Excessive sitting time is widespread and has been shown to be independently associated with the risk of CVD. Since observational studies have shown that interrupting prolonged sitting (PS) is associated with better cardiovascular risk factor profile, many experimental studies have assessed the effects of interrupting PS with physical activity (PA) breaks on postprandial glycemia and insulin responses among various populations. Most, if not all, studies have suggested that interrupting PS with moderate-intensity PA (MPA) to vigorous-intensity PA (VPA) breaks—and even light-intensity PA (LPA) breaks—can lead to positive effects on postprandial glycemia and/or insulin responses. Three pairwise meta-analyses conducted in 2015, 2018, and 2019 synthesized the findings of 6, 20, and 37experimental studies, respectively, and concluded that interrupting PS had positive effects on postprandial glycemia and insulin responses. For the following reason, however, additional research, using a novel network meta-analysis (NMA), is needed to quantitatively review and summarize the latest literature: (1) the conclusions of previous meta-analyses should be revisited given the increased numbers of new publications issued since the meta-analyses were conducted; (2) the optimal strategy for reducing postprandial glycemia and insulin responses among the different interventions should be identified using NMA, which allows for comparing multiple treatments sharing one common comparator treatment that were not directly compared with one another in head-to-head studies; and (3) NMA can integrate evidence retrieved from direct and indirect comparisons and thus has potential to improve the precision of intervention effect estimates.
- Therefore, our review aims to perform an NMA to systematically evaluate the potential effects of various interventions that interrupt PS with PA on the postprandial glycemia and insulin responses among adults without chronic diseases. Identification of the effect of different characteristics of PA interventions that are optimally, or at least minimally, effective as strategies for postprandial glycemia and insulin control will help narrow the range of intervention strategies employed in future research and practice.
- This study aimed to evaluate the effectiveness of physical activity (PA) interrupting prolonged sitting (PS) on postprandial glycemia and insulin responses among adults.
- PubMed, EMBASE, Cochrane Library, Web of Science, CINAHL, PsycINFO, and the China National Knowledge Infrastructure databases were searched through September 30, 2020. Randomized controlled trials (RCTs) that examined the effect of all forms of PA interrupting PS on postprandial glycemia and/or insulin responses among adults without chronic diseases were included in this study. The risk of bias of included studies was evaluated based on the Cochrane tool. A network meta-analysis was performed to estimate the summary standardized mean differences (SMDs) with 95% confidence intervals (95%CIs) with random effects.
- Thirty crossover RCTs were included in our review. These RCTs included 9 types of interventions that interrupted PS. When compared to PS by itself, light-intensity PA intermittent interrupting (LPA-INT) PS and moderate-intensity PA intermittent interrupting (MPA-INT) PS significantly lowered postprandial glycemia (SMD = –0.46, 95%CI: –0.70 to –0.21; SMD = –0.69, 95%CI: –1.00 to –0.37, respectively) and significantly reduced postprandial insulin response (SMD = –0.46, 95%CI: –0.66 to –0.26; SMD = –0.47, 95%CI: –0.77 to –0.17, respectively). Results of the clustered ranking plot indicated that MPA-INT was the most effective intervention in lowering postprandial glycemia and insulin responses.