title: Improving cognition by adherence to physical or mental exercise: a moderated mediation analysis.
abstract: BACKGROUND
  The role of adherence to an intervention is examined to further understand the relationship between performing new challenging activities (either mental or physical ones) and their putative cognitive benefits.
  
  
  METHODS
  Healthy older women (N = 229, age range: 70-93 years) took part in a six-month randomised controlled trial, covering either a physical or mental activity (three × weekly). They completed five tests, measuring episodic and working memory pre- and post-intervention. A moderated mediation model was specified to test the strength of the indirect effect of the activity mode (i.e. physical vs. mental) through adherence (i.e. time spent on course attendance) on levels of baseline cognitive performance.
  
  
  RESULTS
  Both physical and mental activity groups performed better over time than the control group (p < 0.001). Adherence predicted cognitive performance (p = 0.011). The indirect effect of the activity mode on cognitive performance through adherence was especially seen when levels of baseline composite scores were low (p = 0.023).
  
  
  CONCLUSIONS
  Older healthy women can improve episodic and working memory through spending time on a challenging physical or mental activity. Results are most promising for cognitively less fit women. Time spent on course attendance can be interpreted as an adherence indicator that makes a difference for various cognitive outcomes of the intervention.
authors.affiliation: Department of Psychiatry, Charité Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany. Andrea.Evers@charite.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Evers
authors.forename: Verena
authors.initials: V
authors.lastname: Klusmann
authors.forename: Ralf
authors.initials: R
authors.lastname: Schwarzer
authors.forename: Isabella
authors.initials: I
authors.lastname: Heuser
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003072:Cognition Disorders / Q000517:prevention & control / Q000628:therapy*; D015444:Exercise; D005081:Exercise Therapy; D005260:Female; D005500:Follow-Up Studies; D005858:Germany; D006801:Humans; D008568:Memory; D010349:Patient Compliance; D010809:Physical Fitness; D012959:Socioeconomic Factors; D013997:Time Factors; D016896:Treatment Outcome