Psychophysiological foundations of human physical activity behavior and motivation: theories, systems, mechanisms, evolution, and genetics.

Physical activity is a meaningful part of life that starts before birth and lasts until death. There are many health benefits to be derived from physical activity; hence, regular engagement is recommended on a weekly basis. However, these recommendations are often not met. This raises the question: when and why are people motivated to be physically active? Attempts to explain the motivation for physical activity (or lack thereof) have been a research interest for many years and in many disciplines. In this review, we provide evidence suggesting that physical activity behavior and the psychophysiological foundations thereof are influenced by evolution, genetics, life stage, and the environment. The psychophysiological foundations in turn comprise motivational and volitional factors as described in traditional psychological theories, psychological states and traits such as affective and stress reactions, as well as physiological states and systems (e.g., anatomical development and neural networks and transmitters). Importantly, physical activity elicits differential physiological responses and subjective experiences, which may impact future physical activity behavior and motivation. In summary, the interplay of psychophysiological mechanisms and the importance of examining the ultimate mechanism for physical activity behavior are emphasized. The synthesis of knowledge provided in this review provides impetus for theory development and can facilitate the promotion of physically active lifestyles.