Optimal dose and exercise modality to improve HbA1c in older adults with type 2 diabetes mellitus: a systematic review with pairwise, network, and dose–response meta-analyses.

We aimed to compare exercise modalities and evaluate dose–response relationships with glycemic control including continuous aerobic exercise (CAE), resistance training (RT), combined exercise (CE), mind–body exercise (MBE), and high-intensity interval training (HIIT) in older adults with type 2 diabetes mellitus (T2DM). Three databases were searched for randomized controlled trials of exercise interventions in older adults with T2DM reporting glycated hemoglobin (HbA1c). Pairwise, Bayesian network, and dose–response meta-analyses were conducted. Compared with control, HIIT demonstrated the largest estimated reduction (MD = −0.95%; 95% CrI −1.45, −0.49), followed by CE (MD = −0.59%; 95% CrI −0.93, −0.25), CAE (MD = −0.46%; 95% CrI −0.69, −0.24), MBE (MD = −0.42%; 95% CrI −0.76, −0.10), and RT (MD = −0.29%; 95% CrI −0.51, −0.08). Dose–response network meta-analyses suggested a non-linear association between overall exercise dose and HbA1c reduction, with maximal estimated benefits at approximately 704 METs-min/week with the 95% CrI excluding zero between 241 and 920 METs-min/week. HIIT demonstrated the steepest estimated dose–response relationship, but with wider credible intervals. Other exercise modalities showed more gradual dose–response patterns across their estimated effective ranges. Our findings suggest that exercise prescription for older adults with T2DM should be individualized according to exercise modality, dose, and health status. © 2026 Elsevier B.V.