Physically active adults with uncomplicated type 1 diabetes exhibit normal cardiopulmonary exercise test responses versus healthy controls

We investigated whether physically active adults with uncomplicated type 1 diabetes mellitus (T1DM) differ from healthy controls in cardiopulmonary responses during incremental cardiopulmonary exercise testing (CPET). Fifteen adults with uncomplicated T1DM (duration 15 ± 7 years) and 33 matched controls (age, sex, height, and BMI) performed an incremental cycling CPET and self-reported their weekly physical-activity levels. Pulmonary and cardiovascular variables were recorded at rest, ventilatory thresholds 1 and 2, and peak effort, with noninvasive cardiac function assessed by impedance cardiography. Weekly light-intensity activity frequency differed between groups according to the Mann-Whitney U test (p = 0.028), indicating a statistically significant distributional difference. However, the Hodges-Lehmann estimated median difference was not statistically significant because the 95% CI included zero (0-3). No other self-reported physical activity variables differed between the groups. In the linear mixed-effects models, no significant Group effects or Group × Stage interactions were observed for any cardiopulmonary variable during CPET. In this physically active and clinically selected cohort, adults with uncomplicated T1DM showed no statistically detectable differences in cardiopulmonary responses compared with healthy controls under the present CPET conditions. Larger studies are needed to confirm these findings and evaluate potential subclinical hemodynamic or autonomic differences.