Sarcopenia is associated with functional impairments, loss of independence as well as chronic disease risk and poorer prognosis. Sarcopenia is underpinned by dysregulation of muscle protein turnover that results in a net negative muscle protein balance that is the metabolic basis of muscle loss. Age-related alterations in muscle protein turnover are exacerbated by inactivity/disuse and the presence of obesity and lipid excess, highlighting how aspects of biological or lifestyle ageing may accelerate this disease condition. In contrast, those who have participated in long-term exercise training (Master Athletes) generally display an optimal ageing trajectory, underscored by superior skeletal muscle health and performance. Nonetheless, despite these benefits the data from Master Athletes suggests that, to some degree, skeletal muscle deterioration is characteristic to inherent chronological ageing. Specifically, long-term exercise participation may not necessarily prevent/slow sarcopenia, but instead may shift the "set-point" from which deterioration begins. This talk will explore the mechanisms through which chronological and biological ageing processes alter skeletal muscle protein turnover, morphology, and sarcopenia-related outcomes. The conclusion will highlight how sedentarism, obesity and episodic disuse events fuel a vicious cycle of physiological decline, disability and metabolic disease risk that accelerates sarcopenia progression, whereas long-term exercise training and/or physically active living can counteract these detrimental effects to "buy-back" years of good health and function.