title: Resting energy expenditure can be assessed by dual-energy X-ray absorptiometry in women regardless of age and fitness.
abstract: OBJECTIVE
  To evaluate the possibility that measurement of the magnitude and distribution of fundamental somatic heat-producing units using dual-energy X-ray absorptiometry (DXA) can be used to estimate resting energy expenditure (REE) in both young and elderly women with different aerobic fitness levels.
  
  
  METHODS
  Peak oxygen uptake (VO(2) peak) and REE(m) were directly measured in 116 young (age: 22.3+/-2.1 years) and 72 elderly (63.3+/-6.4 years) women. The subjects were divided into four groups according to categories of age and VO(2) peak; young: high fitness (YH, n=58); low fitness (YL, n=58); elderly: high fitness (EH, n=37) and low fitness (EL, n=35). Using DXA, systemic and regional body compositions were measured, and REE(e) was estimated from the sum of tissue organ weights multiplied by corresponding metabolic rate.
  
  
  RESULTS
  Although there were remarkable differences in systemic and regional body compositions, no significant differences were observed between REE(m) and REE(e) in the four groups. REE(e) significantly correlated with REE(m) in elderly as well as young women; the slopes and intercepts of the two regression lines were statistically not different between the elderly and young groups (elderly: y=0.60x + 472, r=0.667; young: y=0.78x + 250, r=0.798; P<0.001, respectively). A Bland-Altman analysis did not indicate bias in calculation of REE for all the subjects.
  
  
  CONCLUSIONS
  These results suggest that REE can be estimated from tissue organ components in women regardless of age and aerobic fitness.
authors.affiliation: Department of Sport Sciences, Graduate School of Human Sciences, Waseda University, Saitama, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Usui
authors.forename: E
authors.initials: E
authors.lastname: Takahashi
authors.forename: Y
authors.initials: Y
authors.lastname: Gando
authors.forename: K
authors.initials: K
authors.lastname: Sanada
authors.forename: J
authors.initials: J
authors.lastname: Oka
authors.forename: M
authors.initials: M
authors.lastname: Miyachi
authors.forename: I
authors.initials: I
authors.lastname: Tabata
authors.forename: M
authors.initials: M
authors.lastname: Higuchi
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D001481:Basal Metabolism; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D015519:Bone Density; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D015203:Reproducibility of Results; D055815:Young Adult