1. Background and study aims During the last decades, the prevalence of (pre)diabetes but also of chronic heart failure (CHF) has increased dramatically. Somehow, both conditions are linked, but the mechanisms involved have not been completely clarified yet. It is clear that the presence of (pre)diabetes in CHF patients affects morbidity and mortality. Although feasibility, safety and beneficial effects of exercise training in CHF are generally acknowledged, its effects on insulin resistance are not well understood. Therefore, the presented study aims to investigate the effect of ET on insulin resistance and the possible link with cardiac function, exercise tolerance, muscle strength and body composition in CHF patients.