title: Leisure-time physical activity does not fully explain the higher body mass index in irregular-shift workers.
abstract: OBJECTIVE
  To elucidate the influence of leisure-time physical activity on body mass index (BMI), appetite-related hormones, and sleep when working irregular shifts.
  
  
  METHODS
  A cross-sectional study was undertaken of 57 male truck drivers, 31 irregular-shift workers and 26 day-shift workers. Participants completed the International Physical Activity Questionnaire and were assessed for BMI. Subjects also provided a fasting blood sample for analysis of appetite-related hormones and wore an actigraphy device for seven consecutive days.
  
  
  RESULTS
  Although leisure-time physical activity (LTPA) was generally low (<150 min/week) in both groups, the irregular-shift workers were more physically active than day-shift workers (99 ± 166 vs. 23 ± 76 min/week, p < 0.01). In spite of this, mean BMI of irregular-shift workers was 2 kg/m² greater than day-shift workers (28.4 ± 3.8 vs. 26.4 ± 3.6 kg/m², p = 0.04). Mean leptin concentration was 61 % higher in irregular-shift workers (5,205 ± 4,181 vs. 3,179 ± 2,413 pg/ml, p = 0.04). Among obese individuals, irregular-shift workers had higher leptin concentration (p < 0.01) and shorter sleep duration (p = 0.01) than obese day-shift workers.
  
  
  CONCLUSIONS
  Elevated BMI was associated with high leptin and low ghrelin levels in this population of irregular-shift workers. No influence of LTPA on appetite-related hormones or sleep duration was found. We conclude that moderate LTPA is insufficient to attenuate the higher BMI associated with this type of irregular-shift work in truck drivers.
authors: School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, Cerqueira César, São Paulo, SP, 01246-904, Brazil, ecmarqueze@usp.br.
authors: Elaine Cristina
authors: EC
authors: Marqueze
authors: Melissa Araújo
authors: MA
authors: Ulhôa
authors: Claudia Roberta
authors: CR
authors: Castro Moreno
mesh_terms: D000328:Adult; D001066:Appetite / Q000502:physiology*; D001334:Automobile Driving; D015992:Body Mass Index; D001938:Brazil; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D054439:Ghrelin / Q000097:blood; D006801:Humans; D007899:Leisure Activities; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood; D012890:Sleep / Q000502:physiology*; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D054439:Ghrelin; D020738:Leptin