USDA/ARS Children's Nutrition Research Center

Energy Metabolism Unit


The whole room indirect calorimeters allow minute to minute measures of oxygen uptake (VO2) and carbon dioxide production (VCO2) to provide measurements of the following:

  • Sleeping and Basal metabolic rates
  • 24 hour total energy expenditure
  • Substrate oxidation
  • Exercise energy expenditure (e.g. biking, walking, running, aerobics, or video game play).

In addition to the whole room calorimeters the unit is equipped with the following

  • Metabolic carts which utilize the ventilated hood technique are also available for the measurement of energy expenditure under resting conditions and during clamp studies.
  • The Exercise Laboratory assesses sub-maximum and maximum VO2 measurements in children and adults using the metabolic carts.

Other Core Services

  • Use of the doubly labeled water method to evaluate free-living energy metabolism.
  • Use and calibration of activity and sleep monitors.

Adjacent CNRC Resources:

  • Body Composition Laboratory.
  • Metabolic Research Unit (MRU) for inpatient and outpatient research studies.
  • Metabolic kitchen for preparation of study meals.
  • Mass Spectrometry.

Uses for Calorimetry


Applications for the calorimeters include studies of obesity, diet, exercise, brown adipose tissue, diabetes, growth hormone deficiency, pregnancy; preschool, childhood, and adolescent growth, energy needs of disorders such as muscular dystrophy, cystic fibrosis, sickle cell anemia, etc. ; validation of field methods of activity monitors, steppers, and body dashboards.

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