Depression: Physical Activity and Prevention Interview with:
George Mammen, PhD Candidate
Health & Exercise Psychology Unit
University of Toronto What are the main findings of the study?


  • 25 out of the 30 studies found PA to protect against depression; majority of these were of high methodological quality
  • Decreasing PA overtime can increase the risk of developing depression; increasing PA overtime can reduce the risk of developing depression
  • In terms of dosage, the review highlighted studies that showed even low levels, such as 20 mins of walking a day, can prevent the onset of depression. Were any of the findings unexpected?

  • It was promising to see so many studies finding a similar protective relationship while they controlled for an array of confounders that relate to either PA or depression (e.g., SES, age, smoking, alcohol use) What should clinicians and patients take away from your report?

  • Clinicians should explain to patients that not only will PA help prevent future chronic diseases such as heart disease, type II diabetes, cancer and stroke; but it can also prevent depression and help sustain positive mental health
  • Patients and the general public, should take this seriously and realize that being active throughout the day goes far beyond the physical benefits generally associated with PA. Everyone should make it a goal to try and be active for at least 20-30 minutes a day. What recommendations do you have for future research as a result of this study?

  • Future research should now look at the exact mechanisms of ‘how’ this protective effect occurs.
  • future research should take into account genetic factors that may play a strong role in this relationship
  • Additionally, a standardized way to subjectively and objectively measure PA is needed in order to decipher the exact dosage of how much PA is needed to help prevent depression.


Physical Activity and the Prevention of Depression: A Systematic Review of Prospective Studies

George Mammen, Guy Faulkner
American Journal of Preventive Medicine – November 2013 (Vol. 45, Issue 5, Pages 649-657, DOI: 10.1016/j.amepre.2013.08.001)


Last Updated on December 21, 2014 by Marie Benz MD FAAD