This paper discusses advancements in research ex- amining the dose-response relationship. Firstly, it will describe the dual-mode theory (Ekkekakis 2003), and highlight the methodological limitations of previous re- search and the mechanisms proposed to be responsible for the exercise intensity–affect relationship. Experi- mental studies that provide empirical evidence for both the methodological and mechanistic proposals will be identified. Secondly, it will briefly explore the potential for individual self-selection of exercise intensities, and exercise self-regulation in an attempt to avoid a level of exercise intensity associated with a negative affective response. Thirdly, it will consider affect as a determi- nant of exercise behavior and consider the potential