Abstract
Sedentary behaviors have become ubiquitous in modern societies. Once considered synonymous with physical inactivity, it is now known that sedentary behavior is its own distinct form of activity on the 24-hour activity continuum separate from both physical inactivity and physical activity. While the positive health ramifications of physical activity on health disease risk and mortality have been known for decades, the negative health risks associated with prolonged and extensive sedentary behaviors are just starting to be recognized. With increased reliance on technology for work (e.g. computers and smart tablets) and leisure (e.g. televisions, video games, social media), screen time and thus time spent in a sedentary posture is increasing around the world. This chapter will address how sedentary behavior influences chronic disease risk, the economic costs associated with sedentary behavior, and future directions pertaining to the interaction between physical activity and sedentary behavior.