Sarcopenia and functional decline: pathophysiology, prevention and therapy.

Twenty years ago, the term 'sarcopenia' has been introduced to describe the ageing related loss of skeletal muscle mass. Since then, sarcopenia has been intensively studied and prevalence values have been reported in fifteen papers covering several continents and races. However, consistency regarding the outcome measures and corresponding cut-off values defining sarcopenia is lacking. Most approaches are based on estimations of muscle mass and proposed cut-off values might be too strict, thus reducing their use in daily practice. From a clinical viewpoint, the assessment of muscle performance (grip strength and endurance) can be proposed as a screening tool showing sufficient sensitivity. The pathophysiology of sarcopenia is multifactorial, and important changes at the tissue level have been identified. Close relationships with inflammatory processes have been demonstrated and there is strong evidence for the involvement of a chronic low-grade inflammatory activity. Sarcopenia is aggravated by a complex interaction of several factors among which aging, disuse, immobilization, disease and malnutrition. A comprehensive geriatric assessment should allow the clinician to estimate the relative contribution of these factors and to elaborate appropriate management. From all interventions studied, intensive resistance training seems the most efficient to counter sarcopenia, even in the very old geriatric patients. Significant ameliorations (up to >50% strength gain) can be expected after six weeks of training at a rhythm of 2-3 sessions per week. From a preventive viewpoint, all elderly patients should be advised to start such an exercise program and continue it as long as possible. To date, most pharmacological interventions to counter sarcopenia include drugs with anabolic effects. Unfortunately, their effect is questionable and no clear guidelines exist for the prescription of these products in the context of sarcopenia.