Sedentary behavior is associated with deleterious health outcomes, which differ from those that can be attributed to a lack of moderate to vigorous physical activity.This paper provides an overview of this emerging fi eld, research and highlights the ways in which it differs from physiology. Defi nitions of key terms associated with the fi eld of sedentary physiology and a review of the self-report and objective methods for assessing sedentary behavior are provided. Proposed mechanisms of sedentary physiology are examined, and how they differ from those linking physical activity and health are highlighted. Evidence relating to associations of sedentary behaviors with major health outcomes and the population prevalence and correlates of sedentary behaviors are reviewed. Recommendations for future research are proposed.