Effects of supervised physical exercise on emotions among adult women with a diagnostic of borderline personality disorder: A series of mixed method single-case experimental trials combined with ecological momentary assessment

Borderline personality disorder (BPD) is thought to be shaped around emotional dysregulation. Physical exercise is an effective way to improve emotional regulation in individuals both with and without mental disorder. However, to this day no study examined the effect of regular physical exercise on emotion regulation in adults with BPD. This study used a series of single case experimental design (A-B-A) combined with ecological momentary assessment and individual interviews to explore and analyze the effect of physical exercise on emotion regulation in adults with BPD. Emotions of participants were monitored thrice daily with an app that prompted them to report their emotions on a 0–100 analogue scale. Both A (control) phases lasted 2 weeks and the B phase (intervention) lasted 4 weeks (3 1-hour supervised sessions of physical exercise weekly). Emotion-related data were analyzed by piecewise linear regression and qualitative data with thematic analysis. Seven women with BPD completed this study and five of them participated in the interviews. Three participants showed an increase in positive emotions and four participants showed a decrease in negative emotions throughout the study and those results are confirmed with interindividual analyses. Participants reported enjoying the exercise program and the trainer they were assigned. Finally, participants also reported being less reactive and more patient when encountering irritating or stressing events. In conclusion, adult women with BPD found that physical exercise decreases their negative emotions and reactivity to psychological stressors.