Effects of 12-week combined interval running and resistance training on cardiac structure and performance in patients with type 1 diabetes

Background Exercise has been suggested to effectively improve cardiac performance in children with Type 1 Diabetes (T1D) by enhancing glycemic control. The purpose of this study was to investigate 1) the effects of a 12 week combined Interval Running and Resistance Training (CIRRT), and 2) 1-month of detraining on cardiac structure and myocardial performance in adolescent males with T1D. Methods A total of 72 participants including 48 adolescent males with T1D (FBG: 274.67 ± 52.99 mg/dl, age: 15.20 ± 1.78 yrs) and 24 healthy adolescents (Fasting Blood glucose؛ FBG: 90.75 ± 5.47 mg/dl, age:15.08±1.67 yrs) were recruited to the study. Participants were allocated into Diabetes Exercise (DE), Diabetes Control (DC), and Healthy Controls (HC) groups. DE group performed 12 weeks of a CIRRT programme three times per week. Blood glucose profile, Echocardiography (ECHO) indices, and peak oxygen consumption (VO2peak) were measured pre- and postintervention and following 1-month detraining period. Repeated measures ANOVA was used for pre- and post-intervention comparisons within the DE group and across the three study groups. Results Exercise intervention resulted in decreased Hemoglobin A1c (HbA1c%=Pre: 10.44 ± 2.03, Post: 9.38 ± 1.66, p < 0.05), FBG, left ventricular internal diameter (LV), and both tricuspid and mitral deceleration time (DT) in the DE group.VO2peak, ejection fraction (EF%= Pre: 62.38 ± 1.6, Post: 64.08 ± 1.18, p < 0.05), fractional shortening (FS), early tricuspid diastolic inflow E velocity, and tricuspid velocity during atrial contraction were also increased following the exercise training. HbA1c (Pre vs. Follow-up: 9.83 ± 1.73, p < 0.05), EF (Pre vs. Follow-up: 62.97 ± 1.56, p < 0.05), LV, and DT tricuspid, remained significantly improved after detraining period compared to the baseline. In the baseline, the glycemic index and ECHO Variable significantly differed in the DE and DC groups with HC group (P<0.05). Conclusions The CIRRT intervention was associated with improved cardiac structure and performance in male adolescents with T1D potentially due to exercise-induced adaptations. Meanwhile, the results indicate that most cardiac morphological and functional changes are reversible following periods of inactivity in patients with T1D.