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

Abstract

Background: Exercise has been suggested to effectively improve cardiac performance in children with type 1 diabetes (T1D) by enhancing the glycemic control. The purpose of this study was to investigate (1) 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 (fasting blood glucose (FBG): 274.67 ± 52.99 mg/dL, age: 15.20 ± 1.78 years) and 24 healthy adolescents (FBG: 90.75 ± 5.47 mg/dL, age: 15.08 ± 1.67 years), were recruited to the study. Participants were allocated into diabetes exercise (DE), diabetes control (DC), and healthy controls (HC) groups. The DE group performed 12 weeks of a CIRRT program three times per week. Blood glucose profile, echocardiography (ECHO) indices, and peak oxygen consumption (VO_2peak) were measured pre- and post-intervention 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. Significance level was set at p < 0.05.

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 (LV) internal diameter, and both tricuspid and mitral deceleration time (DT) in the DE group. VO_2peak, ejection fraction (EF% = Pre: 62.38 ± 1.6, Post: 64.08 ± 1.18, p < 0.05), fractional shortening, 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 the HC group (p < 0.05). However, after the intervention, the DC and HC groups did not change significantly (p > 0.05).

Conclusion: 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.

Keywords: VO2Peak; echocardiography; heart; interval running training; resistance training; type 1 diabetes.

Figure 1.

Study flowchart.

Figure 2.

Fasting blood glucose and HbA1c values with exercise training and detraining. θ, significantly different from baseline in DE group. *, significantly different from baseline. #, significantly different from end of 12 week intervention. DC, diabetes control; DE, exercise diabetes; HbA1c, hemoglobin A1c; HC, healthy control.

Figure 3.

The changes pattern in VO_2peak levels during the study period in three groups. θ, significantly different from baseline in DE group. #, significantly different from 12 week in DE group. DC, diabetes control; DE, exercise diabetes; HC, healthy control; VO_2peak, peak oxygen consumption.

Figure 4.

The changes pattern in EF during the study period in three groups. θ, significantly different from baseline in DE group. #, significantly different from 12 week in DE group. DC, diabetes control; DE, exercise diabetes; EF, ejection fraction; HC, healthy control.

Figure 5.

The changes pattern in LVIDd, LVIDs, tricuspid DT, and mitral DT during the study period in three groups. θ, significantly different from baseline in DE group. #, significantly different from 12 week in DE group. DC, diabetes control; DE, exercise diabetes; DT, deceleration time; HC, healthy control; LVIDd, left ventricular internal dimension during diastole; LVIDs, left ventricular internal dimension during systole.