title: Predictors of Physical Activity After Gastric Bypass-a Prospective Study.
abstract: Most patients do not meet the recommended level of physical activity after bariatric surgery, and psychological factors underlying postoperative physical activity remain poorly understood. This study aimed at identifying self-regulatory predictors of physical activity after bariatric surgery.
  
  
  
  Questionnaire data including self-regulation variables and the short-version of the International Physical Activity Questionnaire were obtained in a prospective cohort of 230 patients 1 year after Roux-en-Y gastric bypass. The study sample consisted of participants consenting to wear an ActiGraph GT3X+ accelerometer for seven consecutive days, 18-24 months after surgery (n = 120).
  
  
  
  A total of 112 participants with complete self-report data provided valid accelerometer data. Mean age was 46.8 years (SD = 9.3), and 81.3% was women. Preoperative and postoperative BMI was 44.8 ± 5.5 and 30.6 ± 5.0 kg/m2, respectively. Total weight loss was 28.9% (SD = 7.5). By objective measures, 17.9% of the participants met the recommended level of moderate-to-vigorous-intensity of physical activity of ≥150 min/week, whereas 80.2% met the recommended level according to self-reported measures. Being single, higher education level, and greater self-regulation predicted objective physical activity in multivariate regression analysis. Greater self-regulation also predicted self-reported physical activity. Weight loss 1 year after surgery was not associated with self-reported or objectively measured physical activity.
  
  
  
  Despite large differences between accelerometer-based and subjective estimates of physical activity, the associations of self-regulatory factors and weight loss with postoperative physical activity did not vary depending on mode of measurement. Self-regulation predicted both objective and self-reported physical activity. Targeting patients' self-regulatory ability may enhance physical activity after gastric bypass.
authors.affiliation: Department of Psychology, University of Oslo, PB 1094, Blindern, 0317, Oslo, Norway. irmelin.bergh@psykologi.uio.no.
authors.forename: Irmelin
authors.initials: I
authors.lastname: Bergh
authors.affiliation: Department of Psychology, University of Oslo, PB 1094, Blindern, 0317, Oslo, Norway.
authors.forename: Ingela Lundin
authors.initials: IL
authors.lastname: Kvalem
authors.affiliation: Center for Morbid Obesity and Bariatric Surgery, Oslo University Hospital, Postboks 4950, Nydalen, 0424, Oslo, Norway.
authors.forename: Tom
authors.initials: T
authors.lastname: Mala
authors.affiliation: Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors.forename: Bjørge Herman
authors.initials: BH
authors.lastname: Hansen
authors.affiliation: Institute of Health & Society, Fuse-The Centre for Translational Research in Public Health Institute of Health & Society Faculty of Medical Sciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle, NE2 4AX, UK.
authors.forename: Falko F
authors.initials: FF
authors.lastname: Sniehotta
mesh_terms: D056044:Actigraphy; D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology*; D005260:Female; D015390:Gastric Bypass / Q000534:rehabilitation* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000175:diagnosis / Q000453:epidemiology / Q000534:rehabilitation / Q000601:surgery*; D011184:Postoperative Period; D011379:Prognosis; D011446:Prospective Studies; D057566:Self Report; D011795:Surveys and Questionnaires; D015431:Weight Loss / Q000502:physiology
keywords: Accelerometer; Bariatric surgery; Behavior change; Gastric bypass; Physical activity; Self-regulation