Spontaneous Physical Activity Defends Against Obesity

Abstract

Purpose of review: Spontaneous physical activity (SPA) is a physical activity not motivated by a rewarding goal, such as that associated with food-seeking or wheel-running behavior. SPA is often thought of as only "fidgeting," but that is a mischaracterization, since fidgety behavior can be linked to stereotypies in neurodegenerative disease and other movement disorders. Instead, SPA should be thought of as all physical activity behavior that emanates from an unconscious drive for movement.

Recent findings: An example of this may be restless behavior, which can include fidgeting and gesticulating, frequent sit-to-stand movement, and more time spent standing and moving. All physical activity burns calories, and as such, SPA could be manipulated as a means to burn calories, and defend against weight gain and reduce excess adiposity. In this review, we discuss human and animal literature on the use of SPA in reducing weight gain, the neuromodulators that could be targeted to this end, and future directions in this field.

Keywords: Animal; Brain; Central nervous system; DREADD; Dynorphin; Eating behavior; Exercise; Food intake; Human; Locomotion; Non-exercise energy expenditure; Obesity; Optogenetics; Orexin; Spontaneous physical activity.

Figure 1

Optogenetic control of orexin neurons and SPA. Orexin-cre::ChR2 mice were stimulated for 2 h (10 sec every 15 sec at 10 Hz) every 6 h across the circadian cycle. Black header bar, lights-off period. Optogenetic stimulation is indicated by the blue bars. * P≤0.05 for pairwise comparison between groups. Y-axis is SPA in minutes, mean ± s.e.m.