title: Within-Person Link between Depressed Affect and Moderate-to-Vigorous Physical Activity in Adolescence: An Intensive Longitudinal Approach.
abstract: BACKGROUND
  During adolescence, young women and men frequently show low physical activity and elevated depressed affect. This study aimed to examine the within-person link between moderate-to-vigorous physical activity (MVPA) and depressed affect in everyday life.
  
  
  METHODS
  Within an intensive longitudinal approach, adolescents (N = 72; 37% young women; M age = 17.36 years; age range: 12-26 years; mid-90% age range: 13-22 years) wore accelerometers to assess their daily MVPA and reported next-morning and same-evening depressed affect in diaries over eight consecutive days. The within-person link between MVPA and depressed affect on the next morning (time-lagged prediction) and the same evening (same-day link) was analyzed with mixed-effects models.
  
  
  RESULTS
  More-than-usual MVPA significantly predicted less next-morning depressed affect on weekdays in young women, to the extent that a 60-min increase in MVPA over the person mean significantly predicted 50 per cent lower next-morning depressed affect.
  
  
  CONCLUSIONS
  This study encourages the development of individually tailored physical activity interventions that could help adolescents enhance their daily amount of unstructured, self-initiated MVPA to reduce depressed affect. This approach may be particularly suitable for young women who have the highest risk for an inactive lifestyle and elevated depressed affect.
authors.affiliation: German Institute for International Educational Research (DIPF), Frankfurt, Germany.|Center for Research on Individual Developmental and Adaptive Education of Children at Risk (IDeA-Center), Frankfurt, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Langguth
authors.affiliation: German Institute for International Educational Research (DIPF), Frankfurt, Germany.|Center for Research on Individual Developmental and Adaptive Education of Children at Risk (IDeA-Center), Frankfurt, Germany.|University of Tübingen, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Schmid
authors.affiliation: German Institute for International Educational Research (DIPF), Frankfurt, Germany.|Center for Research on Individual Developmental and Adaptive Education of Children at Risk (IDeA-Center), Frankfurt, Germany.|University of Tübingen, Germany.
authors.forename: Caterina
authors.initials: C
authors.lastname: Gawrilow
authors.affiliation: University of Aberdeen, Scotland, UK.|Columbia University, USA.
authors.forename: Gertraud
authors.initials: G
authors.lastname: Stadler
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D000328:Adult; D000339:Affect / Q000502:physiology*; D002648:Child; D003863:Depression / Q000523:psychology*; D015444:Exercise / Q000523:psychology*; D005260:Female; D006801:Humans; D033182:Intention; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity / Q000502:physiology; D057185:Sedentary Behavior; D055815:Young Adult
keywords: accelerometry; adolescence; depressed affect; intensive longitudinal design; moderate-to-vigorous physical activity; within-person link