Development and evaluation of a simple calorimeter for the measurement of resting metabolism.

1. A simple calorimeter based on the measurement of oxygen uptake has been developed. 2. A respiratory simulator was used to evaluate oxygen uptake at different flow rates. A known concentration of mixed gases flows into the calorimeter via the respiratory simulator. Oxygen concentration and flow rate were measured and stored to memory for further analysis. 3. Results indicate that large errors occur at low flow rates, but that the error is less than 5% under normal conditions. 4. This device can be used to measure oxygen uptake under resting conditions.