Distinct Patterns of Dynamical Regulation in Passive Sensor Data Following Binge and Purge Behaviors

Binge eating is a cardinal symptom of binge-eating disorder (BED) and bulimia nervosa (BN), while recurrent purging is specific to BN (American Psychiatric Association, 2022). These behaviors are associated with health consequences (e.g., gastrointestinal, cardiovascular, and metabolic problems; Sheehan & Herman, 2015). The distress-regulating effects of binge and purge behaviors are important targets for intervention. The aims of this examination were to characterize the regulatory dynamics of heart rate (HR) and physical activity following binge and purge behaviors, test whether these dynamics were different from control periods, and test whether these dynamics were different from one another.

A subsample of participants (n = 295) from the BEGIN study reported binges and purges using the Recovery Record app for 30 days; Apple Watch devices were used to measure steps and HR. Regulatory dynamics of the velocity and acceleration of HR and steps were modeled using multilevel models.

Regulatory dynamics of HR were different following binges (dysregulated) relative to control periods (homeostatic) and relative to those following purges (mixed). Regulatory dynamics of steps were significantly different following binges (dysregulated) and following purges (homeostatic) relative to control periods (different type of homeostatic) as well as with respect to one another.

Regulatory dynamics of HR and physical activity can be captured using smart watches and modeled using systems models. Regulatory dynamics of HR have promise as a marker of treatment progress in reducing binge eating frequency, and regulatory dynamics of steps have promise as a digital marker of binge and purge behaviors.

Measures from commercial smart watches are able to detect changes in the complex patterning of heart rate and physical activity following binge eating and purging for individuals with BED. Given the cycle of past dynamics relating to future dynamics, the results suggest that these commercial devices could be useful for tracking treatment progress in reducing binge and purge frequency.