Effect of physical activity and different exercise modalities on glycemic control in people with prediabetes: a systematic review and meta-analysis of randomized controlled trials

Front Endocrinol (Lausanne). 2023 Sep 28:14:1233312. doi: 10.3389/fendo.2023.1233312. eCollection 2023.

Abstract

Background: Numerous studies have shown the beneficial effects of exercise on glycemic control in people with prediabetes. However, the most effective exercise modality for improving glycemic control remains unclear. We aimed to assess which exercise training modality is most effective in improving glycemic control in a population with prediabetes.

Methods: We conducted searches in Pubmed/MEDLINE, EMBASE, SPORTDiscus, Web of Science, PEDro, BVS, and the Cochrane Library from inception to June 2022. Included studies reported fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and 2-hour postprandial (2hPP) levels and implemented an exercise program lasting at least 12 weeks in adults with prediabetes. We performed a direct meta-analysis using a random-effects model and a network meta-analysis. Cochran's Q statistic and the inconsistency I2 test were used to assess the heterogenicity between studies.

Results: Twenty trials were included, with 15 trials (comprising 775 participants with prediabetes) combined in the meta-analysis, and 13 in the network meta-analysis. The meta-analysis results did not show a statistically significant reduction in fasting plasma glucose (FPG) after aerobic training (AT) intervention compared to a control group (mean (95%CI) difference = -5.18 (-13.48; 3.12) mg/dL, Z=1.22, p=0.22). However, a difference of -7.25 (-13.79; -0.71) mg/dL, p=0.03, in FPG after interval training (IT) intervention was detected compared to a control group. After resistance training (RT) intervention, FPG was significantly lower -6.71 (-12.65,-0.77) mg/dL, Z=2.21, p=0.03, and HbA1c by -0.13 (-0.55, 0.29), p=0.54, compared to the control group. The impact of RT compared to no intervention on 2hPP was not statistically significant (p=0.26). The network meta-analysis did not show statistical significance. Most of the studies presented an unclear risk of bias, and a low and very low-quality of evidence. According to the GRADE criteria, the strength of the body of evidence was low.

Conclusion: Resistance training and IT had demonstrated benefits on glycemic indices, especially on FPG, in a population with prediabetes. Further studies with larger sample sizes and a more robust methodology that compare different types of exercise modalities, frequencies, and durations, are needed to establish a beneficial exercise intervention.

Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=370688, identifier CRD42022370688.

Keywords: aerobic training; exercise; interval training; prediabetes; resistance training.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adult
  • Blood Glucose
  • Exercise
  • Glycated Hemoglobin
  • Glycemic Control
  • Humans
  • Prediabetic State* / therapy
  • Randomized Controlled Trials as Topic

Substances

  • Glycated Hemoglobin
  • Blood Glucose

Grants and funding

This study was funded by the Ministry of Culture and Sports, High Council of Sports (CSD, Consejo Superior de Deportes), grants for Research Projects in Science and Technology applied to Physical Activity for Health Benefits (AFBS) and Sports Medicine (grant EXP_75081), following a rigorous peer-reviewed funding process. The study was also supported by the Recovery, Transformation, and Resilience Plan, funded by the European Union under NextGenerationEU. The funders had no role in the study design, data collection, analysis, decision to publish, or preparation of the manuscript. «PostDoc (Margalida Comas)» Contract financed thanks to the call for postdoctoral contracts of the Government of the Balearic Islands Funds to AG-P. IR-C was funded by Instituto de Salud Carlos III, grant number CP17/00017.