Capillary glycaemia responses to strength exercises performed before or after high-intensity interval exercise in Type 1 diabetes under real-life settings

This study investigated the influence of performing strength exercises before or after high-intensity interval exercise on glycaemia during and postexercise in T1DM patients. Nine physically active adults with T1DM executed 30 min of strength exercises (SE) (3 sets at 10 RM) before 30 min of high-intensity interval exercise (HIIE) (10 × 60-s bout at ∼90% HRmax interspersed with 60 s recovery) (SE + HIIE) or performed the reverse order (HIIE + SE) or rested in this period. Capillary glucose levels were measured each 15 min during and 60 min postexercise recovery. Significant lower glucose levels were observed in SE + HIIE at 60, 75 and 90 min, in comparison with REST. HIIE + SE lowered glycaemia at 30, 45 and 60 min compared with baseline concentrations, while SE + HIIE postponed this glucose decayment to 60 min, when compared with baseline levels. An increased glycaemia at 105 min compared with end-exercise levels were also observed in HIIE + SE. Carbohydrates ingested during exercise to correct hypoglycemia, insulin dosage at same day before and after protocols, and nocturnal hypoglycemia episodes were similar among the three conditions. It is concluded that the performance of HIIE before SE decreases glycaemia already at the end of first exercise modality, while the reverse order postpones it to the end of second exercise, although HIIE + SE improves glycemic stability throughout recovery. T1DM patients who tend to develop exercise-associated hypoglycemia may perform strength exercises before high-intensity interval exercise in a single session.