Drop-out ratio between moderate to high-intensity physical exercise treatment by patients with, or at risk of, type 2 diabetes mellitus: A systematic review and meta-analysis

•Patients who are overweight, obese, or suffer from metabolic syndrome and type 2 diabetes mellitus trend to avoid physical exercise treatment compared to other medical interventions without physical exercise (e.g. educational strategies).•High intensity exercise protocols did not improve physical adherence despite the shorter time involved.•Although high intensity exercise protocols might face the lack of time barrier, the difficulty to undertake that kind of exercise might be another barrier that should be take into consideration.