Physical activity is recognized as an important lifestyle behavior for weight regulation and obesity prevention and treatment. However, there is variability response to physical activity and its effects on body weight. Physical activity guidelines and recommendations have been promoted to enhance the likelihood of this important lifestyle behavior to effectively prevent and treat obesity. These guidelines typical recommend a specific dose and intensity of physical activity; there are new data emerging, however, to suggest that how and when physical activity is performed may further influence its effect on body weight regulation and related health outcomes. These factors may include time of day, day of week, duration of activity session, intensity of activity session, etc. This session will focus presentation and discussion of these emerging perspectives to disentangle these elements to refine the prescription of physical activity as an important lifestyle behavior for the prevention and treatment of obesity.