The New York Obesity Nutrition Research Center

Whole Room Indirect Calorimetry Core


           The Whole Room Indirect Calorimetry (WRIC) Core Lab was renovated and updated in 2011. It now features three new whole room indirect calorimeters, and related instrumentation, that are described below:

Description of the MAIN whole room indirect calorimeter

Figure 1The MAIN whole room indirect calorimeter chamber (Figure 1) is used for 23-hour studies of energy expenditure and nutrient utilization. The chamber was completely resealed and included installation of new air conditioning and mixing system as well as Internet and cable TV service. This chamber measures 3.30 x 2.79 x 2.41 meters with an internal corrected volume of 21,399 liters. It is equipped with a futon bed as well as restroom facilities. Moreover, subject’s diets are provided through the airlock linking the calorimeter main lab to the chamber. New hand access sampling ports are being installed to allow for blood sampling from the subject during testing. Finally, safety upgrades included installation of new nurse call and intercom systems.




Description of the RMR whole room indirect calorimeter

Figure 2This new whole room indirect calorimeter chamber (Figure 2) is designed specifically for measuring resting metabolic rate (RMR) without the need for a ventilated hood. This chamber eliminates the anxiety that frequently occurs when placing a ventilated hood over the subject’s head. This is especially true in those subjects that have to be measured for several hours for the determination of the thermic effect of various diets. Subject anxiety from the use of ventilated hoods can lead to large errors in RMR. This new chamber also included installation of a new air conditioning and air mixing system. The RMR chamber measures 1.82 x 1.1.0 x 2.53 meters respectively for length, width and ceiling height with an interior volume of 4,950 liters. Moreover, there are two windows in the room that let in natural light and allow the subject to see out during metabolic measurements. The bed mattress rests on top of three phantoms that can be removed, along with the mattress, to accommodate those subjects whom are wheelchair bound or need the use of a medical assistance device. Finally, new hand access sampling ports are being installed to allow for blood sampling from the subject during testing.

Description of the EXERCISE studies whole room indirect calorimeter
 

Figure 3The Exercise Studies (EX) chamber is a 10,300 liter climate controlled empty room (Figure 3). This chamber also underwent extensive renovations that included installation of a new air conditioning and mixing system. It is designed to measure the energy expended and nutrients utilized for just about any exercise activity that can be conducted within this size (2.40 x 2.40 x 2.50 meter) chamber. Moreover, there is a small window and an intercom system to enable monitoring of the subject during the exercise bout. The area is large enough to accommodate just about any type of exercise equipment such as the aerobic step and trampoline pictured in Figure 3. Finally, no head gear is required for metabolic measurements thus eliminating the inherent accuracies that might be caused by such apparatus. Finally, new hand access sampling ports are being installed to allow for blood sampling from the subject during testing.







Instrumentation for all whole room indirect calorimeters
 

Figure 4New research grade instrumentation (Sable Systems International, Las Vegas, NV) for measuring oxygen and carbon dioxide concentrations (model GA-6), as well as flow rate (model FG-1), for each of the new chambers was installed. Rates of oxygen consumption and carbon dioxide production are analyzed utilizing new fuel cell oxygen and infra-red carbon dioxide detectors, respectively. Air flow through the MAIN chamber is maintained at 80, while that for both the EX and RMR chambers, it is maintained at 100 liters/minute. All data are recorded and processed on-line by a computer program that records variables such as oxygen and carbon dioxide gas concentrations, flow, temperature and barometric pressure and computes energy expenditure in real time every minute. This new state of the art instrumentation does not require removal of moisture from the sample gas stream thus eliminating the errors associated with the use of desiccants or chemical scrubbers on oxygen and carbon dioxide gas concentrations caused by un-removed moisture. This is accomplished by utilizing new mathematical algorithms to model out the effects of moisture on both the oxygen and carbon dioxide sensors.

The WRIC Core provides measurements of the following metabolic components:

1) Twenty-four hour energy expenditure

2) Sleeping metabolic rate

3) Resting metabolic rate

4) The thermic effect of food

5) Energetic costs of various exercise activities

            Nutrient utilization, as determined by the respiratory quotient, is determined for each of the above metabolic components.

           The services offered by the WRIC Core will support all existing NIH funded research; the services are likely to lead to the acquisition of data needed to apply for independent research funding. Furthermore, these services will advance knowledge in the field of obesity research and/or provide an educational venue for students. Services and training are rendered on the first come first serve basis with the NYONRC members having the priority over non-members in scheduling and pricing. If you would like to use the WRIC Core services, please complete the online Service Request Form and email the completed form to the Core Director.

            Whole Room Indirect Calorimeter Core Lab services request form

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