title: Accelerometer-Measured Versus Self-Reported Physical Activity Levels and Sedentary Behavior in Women Before and 9 Months After Roux-en-Y Gastric Bypass.
abstract: Roux-en-Y gastric bypass (RYGB) patients report significant pre- to post-surgery increases in physical activity (PA). Conversely, objectively assessed PA does not increase after RYGB. The aim of the study was to compare self-reported and accelerometer-measured changes in moderate-to-vigorous PA (MVPA) and exercise from pre- to post-surgery, in women undergoing RYGB.
  
  
  
  Forty-three women with an average pre-surgery body mass index of 39.2 kg/m2 (SD 3.1) were recruited at Swedish hospitals. PA was measured by the Actigraph GT3X+ and by a previously validated short PA questionnaire, at home visits 3 months before and 9 months after surgery, thus limiting seasonal effects.
  
  
  
  Self-reported time spent in exercise increased with 75 % and time spent in MVPA increased with 51 %, whereas accelerometer-assessed time spent in exercise increased with 0.9 % and time spent in MVPA increased with 2.1 %, from before to after surgery. Correlations comparing accelerometers with the questionnaire were 0.35 (P = 0.02) for MVPA and 0.13 (P = 0.4) for exercise before RYGB and 0.52 (P ≤ 0.001) for MVPA and 0.12 (P = 0.4) for exercise after RYGB.
  
  
  
  Pre- to post-RYGB surgery increases in self-reported PA were not confirmed by accelerometer-measured PA. Thus, health care workers should use objective measures of PA in patients undergoing RYGB, in order to assess whether patients achieve sufficient levels of PA.
authors.affiliation: Child and Adolescent Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, plan 8, 171 77, Stockholm, Sweden. daniel.berglind@ki.se.
authors.forename: Daniel
authors.initials: D
authors.lastname: Berglind
authors.affiliation: Child and Adolescent Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, plan 8, 171 77, Stockholm, Sweden.
authors.forename: Mikaela
authors.initials: M
authors.lastname: Willmer
authors.affiliation: Child and Adolescent Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, plan 8, 171 77, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Tynelius
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ata
authors.initials: A
authors.lastname: Ghaderi
authors.affiliation: Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Näslund
authors.affiliation: Child and Adolescent Public Health Epidemiology, Department of Public Health Sciences, Karolinska Institutet, Tomtebodavägen 18A, Widerströmska huset, plan 8, 171 77, Stockholm, Sweden.
authors.forename: Finn
authors.initials: F
authors.lastname: Rasmussen
mesh_terms: D061725:Accelerometry; D000328:Adult; D015444:Exercise; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000601:surgery / Q000628:therapy*; D057185:Sedentary Behavior; D057566:Self Report; D011795:Surveys and Questionnaires
keywords: Accelerometer; Physical activity; Roux-en-Y gastric bypass; Sedentary behavior; Self-report