The Impact of Diabetes on Exercise Tolerance in Patients After Cardiovascular Events

Background: Diabetes mellitus (DM) is a significant factor affecting prognosis and functional capacity in patients after cardiovascular events. This study aimed to assess the impact of coexisting diabetes on exercise tolerance and hemodynamic parameters in patients qualified for cardiac rehabilitation. Methods: A total of 452 patients (86 women, 366 men; mean age 63.21 ± 7.16 years) who had experienced cardiovascular incidents, including 226 individuals with coexisting DM (DM group) and 226 age- (±1 year) and sex-matched individuals without DM (non-DM group), were included in the analysis. All participants underwent an exercise test using a bicycle ergometer. Clinical data, comorbidities, medication use, left ventricular ejection fraction, and exercise test parameters were evaluated. Results: Patients with DM displayed a higher number of comorbidities (4.29 ± 1.26 vs. 3.19 ± 1.30; p < 0.001), greater medication use (8.71 ± 2.16 vs. 7.83 ± 2.05; p < 0.001), higher body mass (86.93 ± 13.35 kg vs. 80.92 ± 15.25 kg; p < 0.001), and a lower left ventricular ejection fraction (48.78 ± 8.99% vs. 50.01 ± 8.40%; p = 0.002) compared to those in the non-DM group. Diabetic patients also exhibited lower exercise capacity, expressed as peak power per kilogram of body mass (1.05 ± 0.27 W/kg vs. 1.16 ± 0.31 W/kg; p < 0.001). No significant differences were observed regarding absolute peak power or maximum heart rate. Conclusions: In patients after cardiovascular incidents, the presence of diabetes is associated with reduced relative exercise capacity and lower ejection fraction.