Economics of Physical Activity: Determinants and Mechanisms

Findings from kinesiology, medicine, and epidemiology have established the benefits of a physically active lifestyle. However, adolescents and adults in the United States are not sufficiently active. There are significant disparities observed in the prevalence of adolescent and adult physical activity by demographic and socioeconomic characteristics that are persistent over time. My research aims to propose a model of physical activity behavior that is capable of explaining the patterns and trends observed in physical activity levels of U.S. adolescents and adults. Studies in kinesiology and genetics indicate that physical activity is an outcome that starts from a biological foundation, changes in response to past levels of physical activity behavior, and then grows (declines) as a result of physiological feedback mechanisms. Psychology literature emphasizes cognitive and behavioral (i.e., noncognitive skills or personality traits) factors as important influences on physical activity. Specifically, physical activity is a complex behavior dependent on cognition and personality that make up psychic costs of physical activity. These biological and psychological processes underlying physical activity call for a dynamic modeling in which the past is an important determinant of the current level of physical activity. Human capital formation literature in Economics can accommodate these aspects of the behavior. Among alternative models of human capital formation, I propose to use a model of physical activity that is dynamic and is a modified version of the model described by Cunha and Heckman. Accordingly, the model I propose entails a physical activity production technology, the most important features of which are dynamic complementarities in early and late investments and self-productivities and cross-productivities in skill formation. Empirically, I examine whether there is evidence for the presence of the features of this technology that may yield dynamism in the formation of physical activity and inactivity behaviors during adolescence. To my knowledge, this research is the first attempt to treat various aspects of the physical activity behavior in a unified manner under theoretical guidance and to offer a dynamic model of physical activity in Economics that is potentially capable of explaining observations in adolescent and adult physical activity levels in the United States.