David Williams

In the past two to three decades health behavior scientists have increasingly emphasized affect-related concepts (including, but not limited to emotion) in their attempts to understand and facilitate change in important health behaviors, such as smoking, eating, physical activity, substance abuse, and sex. This article provides a narrative review of this burgeoning literature, including relevant theory and research on affective response (e.g., hedonic response to eating and drug use), incidental affect (e.g., work-related stress as a determinant of alcohol use), affect processing (e.g., anticipated regret for illicit sex or skipping an exercise session), and affectively charged motivation (e.g., cigarette craving). An integrative dual-processing framework is presented that suggests pathways through which affect-related concepts may interrelate to influence health behavior.

The low rates of regular exercise and overall physical activity (PA) in the general population represent a significant public health challenge. Previous research suggests that, for many people, exercise leads to a negative affective response and, in turn, reduced likelihood of future exercise. The purpose of this paper is to examine this exercise–affect–adherence relationship from an evolutionary perspective. Specifically, we argue that low rates of physical exercise in the general population are a function of the evolved human tendency to avoid unnecessary physical exertion. This innate tendency evolved because it allowed our evolutionary ancestors to conserve energy for physical activities that had immediate adaptive utility such as pursuing prey, escaping predators, and engaging in social and reproductive behaviors. The commonly observed negative affective response to exercise is an evolved proximate psychological mechanism through which humans avoid unnecessary energy expenditure. The fact that the human tendencies toward negative affective response to and avoidance of unnecessary physical activities are innate does not mean that they are unchangeable. Indeed, it is only because of human-engineered changes in our environmental conditions (i.e., it is no longer necessary for us to work for our food) that our predisposition to avoid unnecessary physical exertion has become a liability. Thus, it is well within our capabilities to reengineer our environments to once again make PA necessary or, at least, to serve an immediate functional purpose. We propose a two-pronged approach to PA promotion based on this evolutionary functional perspective: first, to promote exercise and other physical activities that are perceived to have an immediate purpose, and second, to instill greater perceived purpose for a wider range of physical activities. We posit that these strategies are more likely to result in more positive (or less negative) affective responses to exercise, better adherence to exercise programs, and higher rates of overall PA.