Metabolic Chambers Core


  • Eric Ravussin, Ph.D.


The main goal of the metabolic chambers core is to perform and provide reliable and reproducible assessments of energy expenditure and substrate oxidation in humans. The technique used for these measurements is indirect calorimetry.

Two types of equipment for these measurements are available at the Pennington Center. Metabolic carts (Deltatrac II metabolic monitors) are used for measurements under resting conditions. The Center has eight of those devices, which are used for the assessment of energy metabolism under resting conditions such as resting metabolic rate (RMR) and the acute effects of possible thermogenic stimuli such as a meal or pharmaceutical and herbal compounds. In addition, the metabolic carts are used during insulin clamp studies to calculate glucose oxidation. The carts use the ventilated hood technique which makes measurements over several hours possible. During 2004 and 2005, we performed approximately 1700 measurements for a variety of studies.

For the measurements of energy expenditure and substrate oxidation on a 24-hour basis whole room indirect calorimeters are used. The Center has two metabolic chambers, (10 feet x 12 feet x 8 feet). Because studies include periods of 24 hours up to 7 consecutive days in the chambers, they are designed to provide a pleasant environment to our study participants. During the last few years, the programming of our chambers was updated to allow for minute to minute data output, making the chambers not only useful for the measurements of 24-hour energy metabolism but also for the assessments of acute changes. During 2004 and 2005 we performed close to 450 measurements of 24H energy expenditure for several studies.