Subjective and Behavioral Impulsivity Differentially Moderate Within- and Between-Person Associations Between Physical Activity and Alcohol Consumption.

OBJECTIVE: Evidence indicates a counterintuitive positive relationship between physical activity and alcohol consumption, suggesting that people who engage in more physical activity consume more alcohol. Impulsivity, which has a well-documented role in alcohol use disorders, has been shown to moderate the between-person physical activity-drinking association among emerging adults. However, only a handful of studies have explored within-person associations of physical activity and drinking and potential moderators of this relationship. The current study evaluated the effects of both subjective and behavioral impulsivity on the within- and between-person association between physical activity and alcohol consumption among college students.

METHOD: Undergraduate students ( N = 250) between ages 18 and 25 years were asked to report their daily physical activity and drinking over 21 days. Physical activity was also recorded objectively through Pacer, a smartphone app. Subjective impulsivity was assessed using the UPPS-P Impulsive Behavior Scale, and behavioral impulsivity was evaluated using the Balloon Analogue Risk Task.

RESULTS: Within- and between-subject physical activity-drinking associations were differentially moderated by behavioral impulsivity and self-reported impulsivity. For instance, behavioral impulsivity moderated the within-person association between drinking and self-reported vigorous physical activity, whereas negative urgency moderated the between-person association between drinking and objective physical activity.

CONCLUSIONS: Impulsivity, whether measured subjectively or behaviorally, significantly moderates the physical activity-alcohol consumption association. Importantly, this effect operates differently when predicting variation in behavior within individuals as compared with predicting differences in behavior between individuals.