title: Relationship between physical activity related energy expenditure and body composition: a gender difference.
abstract: OBJECTIVE
  The doubly labeled water method for the measurement of average daily metabolic rate (ADMR), combined with a measurement of basal metabolic rate (BMR), permits the calculation of energy expenditure for physical activity. Thus, the relation between physical activity and body composition (%body fat) can be determined.
  
  
  METHODS
  We analyzed existing data sets with observations on ADMR, BMR, and %body fat including 290 healthy subjects, age 18-49 y, 146 females and 144 males, from 22 different studies.
  
  
  RESULTS
  In a regression analysis, age explained 3-7% and 5-20% of the variation in %body fat in females and males, respectively. Adding physical activity to the model raised the explained variation in %body fat in males (partial r = -0.35, P < 0.01). A higher level of physical activity was related to a lower %body fat. In females, there was no relationship between physical activity and body composition (partial r = 0.00, n.s.).
  
  
  CONCLUSIONS
  In males, there is a significant inverse cross-sectional relationship between activity energy expenditure and percent body fat, whereas no such relationship was apparent in females.
authors.affiliation: Department of Human Biology, Maastricht University, The Netherlands.
authors.forename: K R
authors.initials: KR
authors.lastname: Westerterp
authors.forename: M I
authors.initials: MI
authors.lastname: Goran
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012727:Sex Characteristics