Functional capacity represents an important predictor for cardiovascular and all-cause mortality in patients with
diabetes mellitus (DM). Impaired cardiopulmonary fitness is frequently seen in DM patients, and it might partly explain morbidity and mortality in these patients. There are several potential reasons that could explain impaired functional capacity in DM patients:
hyperglycemia,
insulin resistance, endothelial dysfunction,
inflammation, microvascular impairment, myocardial dysfunction, and skeletal muscle changes. These changes are partly reversible, and improvement of any of these components might increase functional capacity in DM patients and improve their outcome. Physical activity is related with decreased
cardiovascular disease and all-cause mortality in patients with type 2 DM.
Diabetic cardiomyopathy is the most important clinical entity in DM patients that involves
left ventricular diastolic dysfunction and cardiac autonomic neuropathy, which potentially induce
heart failure with preserved ejection fraction. Development of
diabetic cardiomyopathy may slow
oxygen uptake kinetics and affect the cardiorespiratory fitness in DM patients, but it can also induce development of
heart failure. Improvement of functional capacity in DM patients represents an important therapeutic task, and it can be achieved mainly with exercise training and significantly less with pharmacological treatment. Exercise training reduces
body weight and improves
glycemic control, as well as left ventricular structure and function. The aim of this review was to summarize current knowledge about importance of functional capacity in DM patients, as well as possible mechanisms that could explain the relationship between DM and
oxygen kinetics.