Effectiveness of high-intensity interval training combined with resistance training versus continuous moderate-intensity training combined with resistance training in patients with type 2 diabetes: A one-year randomized controlled trial

Aims To evaluate the impact of one-year high intensity interval training (HIIT) combined with resistance training (RT) vs continuous moderate intensity training (MCT) combined with RT on glycaemic control, body composition and cardiorespiratory fitness (CRF) in patients with type 2 diabetes. Materials and Methods A randomized controlled trial included 96 participants with type 2 diabetes for a one-year supervised exercise intervention with three groups: Control, HIIT with RT and MCT with RT). The control group received standard counseling regarding general PA guidelines, with no structured exercise sessions. The main outcome variable was HbA1c (%). Secondary outcomes were other glycaemic variables, body composition, anthropometry measurements, CRF and enjoyment of exercise. Generalized estimating equations (GEE) were used to model outcomes. Results Among the 96 participants enrolled in the intervention, 80 were randomized, with a mean (SD) age of 58.5 years (7.7) and a mean HbA1c of 7.2% (1.6). After adjusting the model for sex and total moderate-to-vigorous physical activity (MVPA), we found that both the MCT with RT (beta, 0.003; P, 0.921) and the HIIT with RT (beta, 0.025; P, 0.385) groups had no effect on HbA1c. A favourable effect was observed in the MCT with RT group, with a reduction in whole body fat index (beta, -0.062; P, 0.022), android fat index (beta, -0.010; P, 0.010) and gynoid fat index (beta, -0.013; P, 0.014). Additionally, CRF increased during the intervention, but only in the MCT with RT group (beta, 0.185; P, 0.019). Conclusions The results from this study suggest that there was no effect of either MCT with RT or HIIT with RT on glycaemic control in individuals with type 2 diabetes. However, the combination of MCT and RT improved body composition and CRF following a one-year intervention.