Work

Impaired Cardiorespiratory Fitness in Type 1 Diabetes Is Associated With Metabolic Inflexibility and Specific Factors According to Sex

Year: 2025

Type: article

Abstract: BACKGROUND: People with long-term type 1 diabetes have reduced cardiorespiratory fitness (CRF). We aimed to assess the influence of body composition, energy substrate use, and blood glucose control on cardiopulmonary exercise test performance in subjects with uncomplicated, long-term type 1 diabetes. METHODS: Observational, cross-sectional study. Subjects with and without type 1 diabetes, paired by sex and age, underwent treadmill cardiopulmonary exercise test, bioelectrical impedance analysis, indirect calorimetry at rest and during exercise. We used the t-pair test; multivariate linear regression models and mediation analysis were used to evaluate determinants of CRF. RESULTS: 54 cases and 54 controls (52% female) were evaluated. The age was 39 (28-46) years, duration of disease 21 ± 10 years. HbA1c 7.9 (7.3-8.7). The baseline physical activity, resting energy expenditure, respiratory quotient and body composition were similar between groups. VO2max was 32 ± 9.2 versus 39 ± 7.9 mL/kg/min (p < 0.01) for cases and controls. Maximum carbohydrate oxidation was 809 (614-1174) versus 1082 (863-1454) (p < 0.01), respectively. In women 73% and 25% of the effect of diabetes status on VO2max were mediated by carbohydrate oxidation and heart rate reserve, respectively. In men 78% and 57% of the effect of diabetes status on VO2max were mediated by carbohydrate oxidation and phase angle, respectively. CONCLUSIONS: Type 1 diabetes group had an altered CRF with lower carbohydrate oxidation. This suggests altered metabolic flexibility due to low substrate availability that could explain the earlier fatigue during intense exercise. There were different determinants of VO2max in persons with diabetes according to sex.

Source: Journal of Diabetes

DOI: 10.1111/1753-0407.70164