Testosterone deficiency and exercise intolerance in heart failure: treatment implications.

Chronic heart failure (CHF) is characterized by a metabolic shift favoring catabolism with impairment in skeletal muscle bulk and function. There is evidence that low plasma levels of testosterone play a role in this shift, and that hypotestosteronemia could be involved in the impairment of skeletal muscle function and exercise tolerance, which characterize CHF syndrome. Testosterone supplementation at replacement doses has been hypothesized as a potential therapy to counteract anabolic deficiency in CHF also acting on pathophysiological mechanisms, which sustain the progression of CHF. Recent studies have indeed indicated that testosterone supplementation increases functional capacity and muscle performance in patients with CHF. This review summarizes current knowledge on the role of testosterone deficiency in exercise intolerance in CHF and the potential implications of testosterone therapy. The links between testosterone and exercise tolerance in CHF, as well as the potential mechanisms of testosterone benefits in CHF syndrome, are also emphasized. Finally, unsolved issues regarding testosterone therapy in CHF and directions for future research are discussed.