The role of exercise in promoting health is well documented; however, older women have the lowest rates of aerobic exercise of any community group. This paper examines psychological variables relevant to women's initial adoption of exercise. While the evidence is limited, it appears that middle-aged and older women have positive attitudes to exercise but seem unable or unwilling to take action. The influence of practical barriers and of broader social attitudes is considered. It is concluded that social psychological variables have had limited success in explaining sex differences in physical activity. An understanding of practical and societal constraints on behavior choice in a broader social context may provide direction for the development of strategies to improve the exercise levels of this community group.