Health-related social control in overweight romantic couples: daily associations with physical activity and affect for targets and agents.

Background: Physical activity is essential for health and wellbeing. However, many individuals fail to reach the recommended levels and obesity rates are increasing. Health-related social control refers to strategies employed by 1 person (agent) to influence another person's (target) health behavior. These strategies can be classified into persuasion (eg, encouraging or motivating) or pressure (eg, nagging or coercing). However, much of the existing research is cross-sectional and mostly focuses on the experiences of the targets.

Purpose: This study investigates how persuasion and pressure within overweight romantic couples relate to outcomes in both agents and targets. Specifically, it examines same-day associations with positive and negative affect, as well as physical activity.

Methods: This study is a secondary analysis of the 14-day follow-up period from a randomized controlled trial. Accelerometers and daily diaries tracked 99 overweight romantic couples. For each outcome and each partner, separate multilevel models were fitted.

Results: Daily persuasion used by agents was associated with increased physical activity in targets and a more favorable affect in agents. Daily pressure was not associated with the physical activity of either partner but was linked to a more unfavorable affect in the agent. Both persuasion and pressure were unrelated to the targets' affect.

Conclusions: Health-related social control in romantic relationships relates to same-day outcomes of both agents and targets. Our findings suggest that health behavior change interventions and weight loss programs could benefit from encouraging persuasion and limiting pressure.