Aging is a complex and multidimensional phenomenon subject to a continual redefining of the physical, social, psychological, and cultural self. The collective of these subtleties poses a number of challenges for policy makers, program and community leaders, health professionals, and researchers when trying to enhance quality of life for older adults through physical activity. In this article we reflect on how we have come to know about aging and physical activity and argue why expanding the research agenda will better get to the "heart" of active living in the later years.