Background: The impact of exercise training on glucagon-like peptide 1 (GLP-1) of people with type 2 diabetes has been investigated and it has been found that it can improve their levels of blood glucose; however, the effect of exercise intervention mode on GLP-1 levels is still controversial. Objective: The purpose of this study was to investigate the duration, mode, and intensity of exercise intervention effect on the levels of GLP-1 by a systematic review and meta-analysis. Data Sources: By March 29, 2020, Google Scholar, PubMed, Medline, Scopus database, Science Direct, and reference lists of articles had been randomly dealing with the subject matter with the purpose of investigating the effect of different variables of duration, short-term, and long-term exercise training on GLP-1 through pre-test and post-tests. Thus, to strengthen the outcome of the present study, sixteen studies with 1562 subjects were included. Results: In the present study, we found a significant change on GLP-1 levels in both types of duration exercise intervention groups (MD: -1.60 pmol/l; 95% CI [-2.20, -1.01]; p ˂ 0.00001). Separately investigated, the level of GLP-1 in short-term training was: MD: -1.26 pmol/l, 95% CI [-1.79, -0.73]; p ˂ 0.00001 and in long-term training it was: -2.76 pmol/l, 95% CI [-5.10, -0.43]; p = 0.02. The intensity of short-term training was between 55 and 65% max HR and for the long-term-training it was 65-85% max HR. Conclusion: In this meta-analysis, it was found that the levels of GLP-1 could be affected by short-term and long-term training with different modes and intensity. As a result, current evidence shows that it may be a good choice for patients with type 2 diabetes to control their blood glucose. The mechanism of this GLP-1 increase has not yet been fully discovered. Further longitudinal studies and exploration into mechanisms of action are required in order to determine the precise role of GLP-1 in insulin responses to an exercise intervention.

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