title: Energy expenditure of elite female runners measured by respiratory chamber and doubly labeled water.
abstract: To determine whether female athletes have unusually low energy requirements as suggested by many food intake studies, energy expenditure (EE) and intake were assessed in nine elite distance runners [26 +/- 3 (SD) yr, 53 +/- 4 kg, 12 +/- 3% body fat, and 66 +/- 4 ml.kg-1.min-1 maximal O2 uptake]. Subjects were admitted to a metabolic ward for 40 h during which 24-h sedentary EE was measured in a respiratory chamber. Free-living EE was then assessed by the doubly labeled water method for the next 6 days while the women recorded all food intake, daily body weight, and training mileage (10 +/- 3 miles/day). Energy intakes estimated from free-living EE (2,826 +/- 312 kcal/day) and body weight changes (-84 +/- 71 g/day) averaged 221 +/- 550 kcal/day in excess of those calculated from food records (2,193 +/- 466 kcal/day). The energy cost of training (1,087 +/- 244 kcal/day) was calculated as the difference between free-living EE and 24-h EE in the respiratory chamber (1,681 +/- 84 kcal/day) corrected for the thermic effect of food of the extra energy intake. These data do not support the hypothesis that training as a distance runner results in metabolic adaptations that lower energy requirements in women.
authors.affiliation: Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85016.
authors.forename: L O
authors.initials: LO
authors.lastname: Schulz
authors.forename: S
authors.initials: S
authors.lastname: Alger
authors.forename: I
authors.initials: I
authors.lastname: Harper
authors.forename: J H
authors.initials: JH
authors.lastname: Wilmore
authors.forename: E
authors.initials: E
authors.lastname: Ravussin
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001835:Body Weight; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D010101:Oxygen Consumption / Q000502:physiology; D012420:Running; D014867:Water
chemical_list: D014867:Water