title: Does Stress Result in You Exercising Less? Or Does Exercising Result in You Being Less Stressed? Or Is It Both? Testing the Bi-directional Stress-Exercise Association at the Group and Person (N of 1) Level.
abstract: BACKGROUND
  Psychosocial stress contributes to heart disease in part by adversely affecting maintenance of health behaviors, while exercise can reduce stress. Assessing the bi-directional relationship between stress and exercise has been limited by lack of real-time data and theoretical and statistical models. This lack may hinder efforts to promote exercise maintenance.
  
  
  OBJECTIVE
  We test the bi-directional relationship between stress and exercise using real-time data for the average person and the variability-individual differences-in this relationship.
  
  
  METHODS
  An observational study was conducted within a single cohort randomized controlled experiment. Healthy young adults, (n = 79) who reported only intermittent exercise, completed 12 months of stress monitoring by ecological momentary assessment (at the beginning of, end of, and during the day) and continuous activity monitoring by Fitbit. A random coefficients linear mixed model was used to predict end-of-day stress from the occurrence/non-occurrence of exercise that day; a logistic mixed model was used to predict the occurrence/non-occurrence of exercise from ratings of anticipated stress. Separate regression analyses were also performed for each participant. Sensitivity analysis tested all models, restricted to the first 180 days of observation (prior to randomization).
  
  
  RESULTS
  We found a significant average inverse (i.e., negative) effect of exercise on stress and of stress on exercise. There was significant between-person variability. Of N = 69, exercise was associated with a stress reduction for 15, a stress increase for 2, and no change for the remainder. We also found that an increase in anticipated stress reported the previous night or that morning was associated with a significant 20-22% decrease (OR = 0.78-0.80) in the odds of exercising that day. Of N = 69, this increase in stress reduced the likelihood of exercise for 17, increased the odds for 1, and had no effect for the remainder. We were unable to identify psychosocial factors that moderate the individual differences in these effects.
  
  
  CONCLUSIONS
  The relationship of stress to exercise can be uni- or bi-directional and varies from person to person. A precision medicine approach may improve exercise uptake.
authors.affiliation: Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, Boardman 110, P.O. Box 208056, New Haven, CT, 06520, USA. matthew.burg@yale.edu.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Burg
authors.affiliation: Department of Psychiatry and Behavioral Science, Stony Brook University, Stony Brook, NY, USA.|Center for Behavioral Cardiovascular Health, Columbia University Medical Center, New York, NY, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Schwartz
authors.affiliation: Center for Behavioral Cardiovascular Health, Columbia University Medical Center, New York, NY, USA.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Kronish
authors.affiliation: Center for Behavioral Cardiovascular Health, Columbia University Medical Center, New York, NY, USA.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Diaz
authors.affiliation: Columbia School of Social Work, Columbia University, New York, NY, USA.
authors.forename: Carmela
authors.initials: C
authors.lastname: Alcantara
authors.affiliation: Center for Behavioral Cardiovascular Health, Columbia University Medical Center, New York, NY, USA.
authors.forename: Joan
authors.initials: J
authors.lastname: Duer-Hefele
authors.affiliation: Center for Behavioral Cardiovascular Health, Columbia University Medical Center, New York, NY, USA.
authors.forename: Karina W
authors.initials: KW
authors.lastname: Davidson
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D056044:Actigraphy; D000072860:Ecological Momentary Assessment; D015444:Exercise / Q000502:physiology; D017063:Outcome Assessment, Health Care; D013315:Stress, Psychological / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic
keywords: Exercise; Stress