In older adults, physical inactivity exacerbates the age-related decline in physical function, which causes frailty, impairs quality of life, and results in increases in nursing home admissions. Scientific evidence demonstrate that regular physical activity provides substantial health benefits: in older adults, as in younger individuals, regular physical activity is associated with a reduced risk of various chronic health conditions, including certain types of cardiovascular and musculoskeletal disease (sarcopenia and osteoporosis) and certain forms of cancer (breast, colon). Regular physical activity is also associated with many aspects of better mental and psychosocial health such as a depressive mood state and a poor quality of life. Given the breadth and strength of the evidence, physical activity should be one of the highest priorities for preventing and treating disease and disablement in older adults. However, although current recommendations encourage activity on most or all days of the week, only 31 percent of persons 65 to 74 years of age report regularly engaging in moderate physical activity for 20 minutes or more three days a week. Given that many of the acute benefits are lost within a few weeks of ceasing exercise, it is important that elderly people are encouraged to engage in modest levels of voluntary physical activity that they are likely to maintain, rather than focus on a short-term regimen of intensive and closely supervised training.