A simplified technique for measurements of energy expenditure and substrate oxidation in man.

A technique is described for simultaneous measurements of energy expenditure and oxidation of exogenous substrates in man. The equipment comprised a semi-opened respiratory hood operated by a negative-flow pressure of the gas flow through the system. The system was constructed by assembling commercially available components with high analytical precision into an integrated constellation. We present results of instrument accuracy, assessed by calibration, and the coefficient of variation (CV) for calibration procedures of the total system, as well as findings with regard to the degree of reproducibility of applied investigations on both healthy volunteers and hospitalized patients. The overall coefficient of variation was 3-4% of the mean values for RQ and energy expenditure. This includes both biological and methodological variation. The cost of this system is less than that for a commercially available system with a similar performance.