title: Peak fat oxidation during self-paced activities of daily life: influence of sex and body composition.
abstract: BACKGROUND
  Increasing physical activity is a cornerstone in the treatment of overweight individuals and self-selected exercise intensity leads to higher adherence to physical activity. However, information on differences in energy expenditure and fat oxidation between sexes regarding common self-paced activities of daily living are rare.
  
  
  METHODS
  We divided 33 subjects into normal weight (NW, N.=21) and overweight (OW, N.=12). Energy expenditure and substrate oxidation was measured during six self-paced physical activities of daily living using a portable spirometric system. We also determined maximum aerobic capacity (VO2max) and estimated free-living physical activity with a multi-sensor device.
  
  
  RESULTS
  For all six activities, total energy expenditure was not different between NW and OW subjects in both sexes. The peak fat oxidation during physical activities was reached at higher intensities for women (NW 57±15%; OW 53±8% of VO2max) compared to men (NW 41±8%; OW 42±9% of VO2max) with no differences between NW and OW subjects. The majority of OW (92%) but not NW (42%) subjects reached their highest fat oxidation during walking. The self-selected walking speed was not significantly different between NW and OW men (NW 5.25±0.48 km/h, OW 5.52±0.42 km/h) and NW and OW women (NW 5.16±0.89 km/h, OW 5.01±0.42 km/h).
  
  
  CONCLUSIONS
  When physical activity aims to maximizing fat oxidation, women should exercise at higher relative intensities than men, regardless of being normal weight or overweight. Self-paced walking is a suitable activity for overweight subjects to achieve high rates of both total energy expenditure and fat oxidation.
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany - grams.lena@mh-hannover.de.
authors.forename: Lena
authors.initials: L
authors.lastname: Grams
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany.
authors.forename: Momme
authors.initials: M
authors.lastname: Kück
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Haufe
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Tegtbur
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany.
authors.forename: Anne-Katrin
authors.initials: AK
authors.lastname: Nelius
authors.affiliation: Hannover Medical School, Institute of Sports Medicine, Hannover, Germany.
authors.forename: Arno
authors.initials: A
authors.lastname: Kerling
mesh_terms: D000203:Activities of Daily Living; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D001823:Body Composition; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D050177:Overweight; D012737:Sex Factors; D016138:Walking