PHYSICAL ACTIVITY AND AGING: Physical activity prevents some age-related impairment. Physical activity reduces the decline of physical capacity which remains limited by maximal heart rate, and reduces the incidence of cardiovascular diseases by decreasing and preventing associated risk factors. Physical activity reduces age-related bone loss, its effect being potentialized by hormonal replacement therapy, and improves balance function, leading to a lower incidence of falls and fractures in older subjects. Physical activity helps to preserve nutritional balance and lean mass/fat mass ratio and reduces age-related insulin resistance. Moreover, physical activity has a beneficial influence on psychological function by improving cognitive performances and decreasing incidence of depression. Lastly, physical activity seems to reduce the incidence of several cancers, colic and mammary cancers particularly. PHYSICAL ACTIVITY, QUANTITY AND QUALITY OF LIFE: These multiple actions explain that physical activity, if it's adapted to subject's specificities increases longevity, delay entry in dependence and improves quality of life in older subjects. WHAT ARE THE RECOMMENDED ACTIVITIES: There is a superiority of individualized programs giving greater place to warm-up and associated endurance and resistive exercises intended to improve simultaneously cardiovascular and muscular functions. SPECIAL INTERESTS OF PHYSICAL ACTIVITY IN FRAIL AND VERY OLD SUBJECTS: Throughout its beneficial effects on aerobic capacity, muscular function, social integration, cognitive function and autonomy, physical activity may have a particular interest in frail subjects, when programs are adapted to physical capacities of these subjects and associated with nutritional supplements.