Abstract
Rumination is commonly experienced in response to stressful events and has been linked to adverse psychological outcomes. However, research has predominantly examined rumination as a predictor or consequence of psychological functioning, whereas less is known about factors associated with its day-to-day fluctuations. The current study addressed this gap by examining factors associated with rumination using an intensive longitudinal design. A total of 91 young adults (81,5% female; 14,1% male; 4,3% diverse or preferred not to disclose their gender; aged 18–30 years) participated in a 28-day experience-sampling study. Daily self-reported rumination, stress, and subjective sleep quality (SSQ), as well as accelerometry-derived total sleep time (TST), sleep efficiency (SE), and physical activity, were assessed. Multilevel analyses showed that daily stress was associated with greater rumination. Although physical activity was not directly associated with rumination, it moderated the association between stress and rumination. Higher-than-usual physical activity levels were associated with a smaller difference in rumination between stressful and non-stressful days. Better SSQ was independently associated with lower rumination, whereas TST and SE were not. Higher baseline depressive symptom severity was also associated with greater rumination but did not moderate the stress–rumination association. These findings highlight physical activity as a potential protective factor in stress-related rumination and demonstrate the value of examining rumination as a dynamic outcome in everyday life.