Studies supporting the notion that physical activity and exercise can help alleviate the negative impact of age on the body and the mind abound. This literature review provides an overview of important findings in this fast growing research domain. Results from cross-sectional, longitudinal, and intervention studies with healthy older adults, frail patients, and persons suffering from mild cognitive impairment and dementia are reviewed and discussed. Together these finding suggest that physical exercise is a promising nonpharmaceutical intervention to prevent age-related cognitive decline and neurodegenerative diseases. 1. Introduction Chronological aging, or senescence, is associated with an increased risk of chronic conditions and diseases such as cognitive impairment, cardiovascular disease, and metabolic syndrome. Due to prolonged life expectancy, age-related diseases have increased in alarming proportions in recent decades . An increasing body of studies have suggested that lifestyle factors have a significant impact on how well people age. For example, Fratiglioni et al.  reported that three lifestyle factors can play a significant role in slowing the rate of cognitive decline and preventing dementia: a socially integrated network, cognitive leisure activity, and regular physical activity. In this review and others [3, 4], it is argued that out of these lifestyle factors, physical activity has the most support as protective against the deleterious effects of age on health and cognition. Broadly defined, physical activity refers to activity that is part of one’s daily life involving bodily movements and the use of skeletal muscles. Physical exercise is a subcategory of physical activity that is planned, structured, and purposive to improve specific physical skills or physical fitness. Evidence suggests that physical activity and exercise can to some extent lower the risk of adverse outcomes associated with advancing age. Physical activity maintained throughout life is associated with lower incidence and prevalence of chronic diseases such as cancer, diabetes and cardiovascular and coronary heart diseases [5, 6]. Recent studies suggest that physical exercise also protects against dementia . Yet, despite this promise, the ways in which physical activity impacts the rate and prevalence of cognitive decline is still under investigation. Furthermore, several open issues call for further research, such as the dose-response relationship, the level of change or protection provided by physical activity, the biological and/or psychological
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