This is the second of a three-volume series to define our current knowledge and future directions to address issues of active living, cognitive functioning and ageing. This book continues to expand on our understanding by examining whether and how physical activity could indirectly affect cognitive function by influencing mediators that provide physical and mental resources for cognition.This volume also seeks to identify and study key sources of individual variations or differences in exercise and cognitive processes. Internationally known experts provide a review of the "state of knowledge" for their topics. At the beginning of each chapter, an introduction to the contributor is presented along with editors' notes on how the chapter fits into the general model introduced to organise the volume contents.Following each chapter, a summary provides the reader not only with highlights of the chapter, but also a flavour of either the consensus or controversies associated with the topic.