Aims/hypothesis: This study aimed to systematically review randomised controlled trials comparing the effects of aerobic exercise training (AET), resistance training (RT) and combined training (CT) on glycaemic control and blood lipids in patients with type 2 diabetes mellitus.
Methods: Searches were performed in MEDLINE, EMBASE and the Cochrane Library. Inclusion criteria were: type 2 diabetes mellitus, adult, supervised training and a minimum intervention period of 8 weeks. Pooled effects were calculated by fixed/random effect pairwise and Bayesian fixed/random effects network meta-analyses.
Results: A total of 14 trials enrolling 915 participants were included. AET was more effective than RT in improving HbA1c levels (mean difference [MD] -0.20% [-2.2 mmol/mol]; 95% CI -0.32, -0.08; p = 0.0007, 10 trials/515 participants) and fasting glucose (MD -0.9 mmol/l; 95% CI -1.71, -0.09; p = 0.03, 8 trials/245 participants). Compared with AET, CT resulted in a significantly more pronounced reduction in HbA1c (MD -0.17% [-1.87 mmol/mol]; 95% CI -0.31, -0.03; p = 0.02, 9 trials/493 participants). Compared with RT, the MD of the change in HbA1c (MD -0.62%, [-6.82 mmol/mol]; 95% CI -0.95, -0.30; p = 0.0002, 5 trials/362 participants], fasting glucose (MD -1.99 mmol/l; 95% CI -3.07, -0.90; p = 0.0003, 3 trials/99 participants) and triacylglycerols (MD -0.28 mmol/l; 95% CI -0.46, -0.10; p = 0.003, 4 trials/213 participants) were all in favour of CT. The exclusion of trials with a high risk of bias yielded only non-significant results.
Conclusions/interpretation: The present data suggest that CT might be the most efficacious exercise modality to improve glycaemic control and blood lipids. Interpretation with respect to clinical relevance is limited by the low quality of the studies included and the limited information on the clinically important outcomes or adverse effects of exercise.