“…Instead of grouping people into more or less active groups, we aimed at relating within-person variations in physical activity to within-person variations in depressive mood. So far, very few studies examined within-person associations between physical activity and depressive mood, or more broadly, affect in everyday life using intensive longitudinal designs, and these studies typically focused on samples of younger adults (e.g., Bossmann, Kanning, Koudela-Hamila, Hey, & Ebner-Priemer, 2013;Kanning & Schlicht, 2010;Langguth, Schmid, Gawrilow, & Stadler, 2016;Reichert et al, 2016;Schwerdtfeger, Eberhardt, Chmitorz, & Schaller, 2010). For example, a recent study investigated within-person associations between physical activity and affect in younger adults over 10 consecutive days (Haas, Schmid, Stadler, Reuter, & Gawrilow, 2017).…”