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Eur J Appl Physiol (2012) 112:345355 DOI 10.1007/s00421-011-1985-1
ORIGINAL ARTICLE
Validity of the Oxycon Mobile metabolic system under eld measuring conditions
Jane Salier Eriksson Hans Rosdahl
Peter Schantz
Received: 3 December 2010 / Accepted: 27 April 2011 / Published online: 11 May 2011 Springer-Verlag 2011
Abstract This study aimed to validate a portable metabolic system in eld measuring conditions, such as prolonged moderate exercise at low temperatures, high humidity and with external wind. VO2, VCO2, RER and VE were measured using the Oxycon Mobile (OM), with a windshield, during cycle ergometer exercise: (1) indoors at three submaximal workloads with no wind or with external wind (1320 m s-1) from front, side and back; (2) at two submaximal workloads outdoors (12 2C; 86 7%
relative humidity (RH)), with and without a system for drying the ambient air around the air sampling tube; and (3) at one workload outdoors for 45 min (5 4C;
69 16.5% RH). Any physiological drift was checked for with pre- and postmeasurements by the Douglas bag method (DBM). A minor effect of external wind from behind was noted in RER and VE (-2 and -3%). The system for drying the ambient air around the gas sampling tube had no effect on the measured levels. A small difference in VCO2 drift between the OM and DBM(1.5 mL min-2) was noted in the stability test. The results indicated that heavy external wind applied from different
directions generally does not affect the measurements of the OM and further that, when using a unit for drying the ambient air around the gas sampling tube, the OM can accurately measure VO2, RER and VE at submaximal workloads for at least 45 min under challenging conditions with regard to humidity and temperature.
Keywords Oxycon Mobile Douglas bag method
External wind Humidity Temperature Stability
Introduction
Measuring oxygen uptake (VO2), carbon dioxide production (VCO2) and ventilation (VE) within a wide spectrum of physical activities and conditions in humans has intrigued scientists for more than two centuries (Mitchell and Saltin 2003). The German physiologist Nathan Zuntz was a pioneer in the search for mobile possibilities in this respect, and in the late 1800s he developed a device for that purpose (Tipton 2006). However, it was with the Douglas bag method (DBM)...