A dual-respiration chamber system with automated calibration

Paul F. M. Schoffelen, Klaas R. Westerterp, Wim H. M. Saris, and Foppe Ten Hoor Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands Received 12 March 1997; accepted in final form 23 July 1997. Schoffelen, Paul F. M., Klaas R. Westerterp, Wim H. M. Saris, and Foppe Ten Hoor. A dual-respiration chamber system with automated calibration. J. Appl. Physiol. 83(6): 2064-2072, 1997. This study characterizes respiration chambers with fully automated calibration. The system consists of two 14-m 3 pull-type chambers. Care was taken to provide a friendly environment for the subjects, with the possibility of social contact during the experiment. Gas analysis was automated to correct for analyzer drift and barometric pressure variations and to provide ease of use. Methods used for checking the system's performance are described. The gas-analysis repeatability was within 0.002%. Results of alcohol combustion (50-350 ml/min CO 2 ) show an accuracy of 0.5 ± 2.0 (SD) % for O 2 consumption and 0.3 ± 1.6% for CO 2 production for 2- to 24-h experiments. It is concluded that response time is not the main factor with respect to the smallest practical measurement interval (duration); volume, mixing, gas-analysis accuracy, and levels of O 2 consumption and CO 2 production are at least equally important. The smallest practical interval was 15-25 min, as also found with most chamber systems described in the literature. We chose to standardize 0.5 h as the minimum measurement interval. indirect calorimetry; energy expenditure; oxygen consumption and carbon dioxide production; measurement interval 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society