There is no dose–response relationship between the amount of exercise and improvement in HbA1c in interventions over 12 weeks in patients with type 2 diabetes: a meta-analysis and meta-regression

Abstract

Abstract Aims Aerobic exercise is well recognised as an effective treatment for people with type 2 diabetes but the optimal amount of aerobic exercise to improve glycaemic control remains to be determined. Thus, the aim of this meta-analysis and meta-regression was to assess the impact of volume and intensity of aerobic exercise on glycaemic control. Methods Medline, Cochrane, Embase, and Web of Science databases were searched up until 15 December 2020 for the terms “aerobic exercise AND glycaemic control”, “type 2 diabetes AND exercise”, and “exercise AND glycaemic control AND Type 2 diabetes AND randomised control trial”. We included (i) randomised control trials of ≥ 12 weeks, (ii) trials where participants had type 2 diabetes and were aged 18 or over, and (iii) the trial reported HbA1c concentrations pre- and post-intervention. Two reviewers selected studies and extracted data. Data are reported as standardised mean difference (SMD) and publication bias was assessed using funnel plots. Results A total of 5364 original titles were identified. Sixteen studies were included in the meta-analysis. Aerobic exercise reduced HbA1c versus control (SMD = 0.56 (95% CI 0.3–0.82), p < 0.001). There were also significant reductions in BMI (SMD = 0.76 (95% CI 0.25–1.27), p < 0.05). There was no dose–response relationship between improvement in HbA1c and the intensity and volume of the intervention (p > 0.05). Conclusions Twelve-week or longer aerobic exercise programmes improve glycaemic control and BMI in adults with type 2 diabetes. Longer or more intense interventions appear to confer no additional benefit on HbA1c.