Abstract The term sarcopenia is defined as the loss of mass and muscular function with age. It is characterized by a metabolic status in which the muscles present a reduced abil- ity to produce and use energy. Thus, in humans between 20 and 80 years of age, muscle mass decreases about 40%, with negative effects on mobility, strength production, metabolic rate and respiratory function. A continuous reparative process is also present in skeletal muscle due to the presence of quiescent adult stem cells, called satellite cells, which are able to change their phenotype when appropriate conditions are present. Sarcopenia is considered an event with a multi- factorial etiology: (1) mitochondrial deletion, i.e., replication errors in mitochondrial DNA that lead to an energetic deficit and fiber atrophy; (2) protein synthesis alterations, with an imbalance between protein degradation and the ability of the fibers to synthesize protein; (3) loss of repair ability of the satellite cells, caused by an alteration in the proteic growth factors (mainly IGF-1, mIGF-1, HGF) and hormones (growth hormone, testosterone and estrogens), or by an im- balance of the antioxidant system. We are still far from a complete understanding of the causes and characteristics of the sarcopenic process, and from a solution to the problem. However, a suitable lifestyle (programmed physical training) and a suitable diet (caloric restriction) seem to be the most effective therapeutic approaches in order to control at least the more alarming symptoms of sarcopenia. Key words Sarcopenia • Physical activity • Satellite cells Introduction Sarcopenia is a term coined by Irwin Rosenberg (Tufts University, Boston, USA) in 1988 to define the loss of mass and muscular function with age [1]. It can be identified with the metabolic condition when the muscle, one of the most important energy consumers of the body (because it repre- sents approximately 40% of body mass and has high unitary metabolic capacity), gradually loses, from about 45 years of age, its ability to produce and consume energy at the same rate as before. Moreover, taking into account that the de- creased physical ability leads unavoidably to a parallel de- crease in activity, then, in the absence of a suitable dietary adaptation, the ratio of fat to lean mass inevitably grows ex- ponentially. What are the consequences of this situation, which cannot be considered pathological since each of us is bound to lose approximately 40% of our muscular mass (the decrease is more evident in men than in women), when passing from 20 to 80 years of age? The consequences are REVIEW G. Di Tano • S. Fulle • T. Pietrangelo • R. Bellomo • G. Fanò Sarcopenia: characteristics, genesis, remedies G. Di Tano • S. Fulle • T. Pietrangelo • R. Bellomo • G. Fanò () Aging Study Center (CeSI) Interuniversity Myology Institute Faculty of Medicine and Pharmacy G. D’Annunzio University Via dei Vestini 29, I-66013 Chieti, Italy E-mail: fano@unich.it Sport Sci Health (2005) 1:69–74 DOI 10.1007/s11332-2005-004-0013-4 Received: 30 October 2004 / Accepted: 9 March 2005