title: The Effect of Changes in Physical Activity on Sedentary Behavior: Results From a Randomized Lifestyle Intervention Trial.
abstract: OBJECTIVE
  To investigate whether changes in physical activity (PA) have an impact on sedentary behavior (SB) during a lifestyle intervention.
  
  
  METHODS
  Study design was a randomized trial.
  
  
  METHODS
  Participants (n = 204) were individuals with low PA and high sedentary leisure screen time from the Chicago area.
  
  
  METHODS
  Participants were randomized to either increase PA (iPA) or decrease sedentary leisure (dSED). The intervention consisted of decision support, coaching, and financial incentives. For iPA participants, the goal was at least 60 min/d of self-reported moderate-tovigorous-intensity PA (MVPA). For dSED participants the goal was less than 90 min/d of sedentary leisure screen time.
  
  
  METHODS
  Daily accelerometer-based measures of SB and bout-corrected MVPA were obtained.
  
  
  METHODS
  Linear mixed-effects models were fit to estimate the effect of the intervention on MVPA and total SB and to estimate the effect of daily changes in MVPA on daily SB.
  
  
  RESULTS
  The iPA participants increased their bout-corrected MVPA by 14 min/d (p < .001) and decreased their total SB by 18 min/d (p < .001). The dSED participants did not significantly change their PA or their total SB. On days when participants exercised, each 10-minute bout of MVPA was associated with a 6-minute decrease in SB on the same day (p < .001).
  
  
  CONCLUSIONS
  In an intervention study designed to increase MVPA, participants who increase their time spent exercising will obtain much of this time by reducing their SB.
authors.affiliation: 1 Department of Preventive Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Juned
authors.initials: J
authors.lastname: Siddique
authors.affiliation: 1 Department of Preventive Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Peter John
authors.initials: PJ
authors.lastname: de Chavez
authors.affiliation: 1 Department of Preventive Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Lynette L
authors.initials: LL
authors.lastname: Craft
authors.affiliation: 2 Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts.
authors.forename: Patty
authors.initials: P
authors.lastname: Freedson
authors.affiliation: 1 Department of Preventive Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Spring
mesh_terms: D061725:Accelerometry; D000328:Adult; D002641:Chicago; D004032:Diet; D015444:Exercise; D015438:Health Behavior; D006293:Health Promotion / Q000379:methods*; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D057185:Sedentary Behavior; D012959:Socioeconomic Factors
keywords: Accelerometry, Compensation, Exercise, MVPA, Prevention Research. Manuscript format: research; Health focus: fitness/physical activity; Outcome measure: behavioral; Research purpose: modeling/relationship testing; Setting: local community; Strategy: skill building/behavior change; Study design: randomized trial; Target population age: adults; Target population circumstances: geographic location