## 4 Discussion
[48], subjects had T2 DM and the intervention was in the form of 3 min sessions of simple resistance activities after every 30 min of interrupted sitting. [PERSON] et al. [28] studied the effects of interrupted sitting with 5 min of arm ergometry every 30 min in 34 healthy adults. These results remind us of the importance of RE. Therefore, it can be inferred that RE has a significant effect on prandial glucose management; however, more research is needed to confirm this hypothesis. The glucose- and insulin-level lowering effects were also relatively clear in the study by [PERSON] et al. [25], in which subjects were 22 overweight or obese postmenopausal women. In our subgroup analyses of more than a 5 min interruption and its effects on glycemia and insulin, we found different effect estimates, without significant heterogeneity between studies. This is most likely due to the different samples included. For example, of the three studies that included blood glucose, two had an average participant age of 60 or older, and one had a sample of patients with T2 DM. The participants in the four insulin studies were young and healthy. No significant reduction in glucose and insulin levels was observed with 45 min, 60 min, and three 15 min exercise sessions. A 30 min exercise session showed an SMD of \(-\)0.89 (95%CI: \(-\)1.51 \(-\)0.27) for insulin. Our review shows that sitting with activity breaks every 20 and 30 min is beneficial for blood glucose and insulin levels in a sample including healthy, overweight, obese, and inactive adults, as well as those with impaired glucose tolerance and diabetes. The activity breaks in the studies usually involved walking or simple weightlifting. Durations of 5, 3, and 2 min showed significant effects on both glucose and insulin. Overall, our study has some strengths. First, every study incorporated in our meta-analysis employed a randomized, controlled, cross-over methodology. In addition, a network meta-analysis was used to simultaneously compare the effects of multiple physical activity interventions with greater accuracy [62]. However, our study also has some limitations. Firstly, the small sample size of the included studies and the heterogeneity of the measurement methods--as well as the heterogeneity of the interventions in the control for duration, frequency, and intensity--were potential confounding factors for the reported results. This study was limited by the acute nature of metabolism, and, thus, the validity of long-term results cannot be determined. In the future, the long-term longitudinal-effect RCTs of PA breaks should be carried out to investigate the long-term metabolic effects of these interventions, as well as their effectiveness and feasibility in life, especially for patients with, or at high risk of, T2 DM. In addition, there was a small number of RE intervention studies with prediabetes/diabetes participants, so results were unclear for these subgroups. Consequently, additional studies are required to comprehend the possible immediate and delayed impacts of these interventions on postprandial metabolism. Although we were not able to resolve queries about the potential sources of bias, the experimental design and PA interventions were well controlled, with the washout period removing any potential carryover effects from the previous trial.