A Methodology to Assess the Accuracy of a Portable Metabolic System (VmaxSTTM)

Publisher Website
Google Scholar
Abstract
A mechanical system (GESS) and during human exercise. Methods: Three tests were conducted while gas exchanges were measured continuously by VmaxSTTM. Test 1 was composed of six simulations of gas exchanges during steady-state exercise (20 min at [latin capital V with dot above]E = 80 L·min-1). Test 2 was composed of seven simulations of gas exchanges during incremental exercise ([latin capital V with dot above]O2 from 300 to 5600 mL·min-1). In the human trial, 11 subjects performed an incremental running exercise on a treadmill while gas exchanges were measured at the end of each stage with the Douglas bag method (DBM). Results: Test 1 showed that the VmaxSTTM measurements were stable, despite inaccurate measurements of gas concentrations at the start of the test. During test 2, the mean error (difference between measured and predicted value) and the upper and lower limits of agreement were -8.0%, -12.6%, and -3.4% for [latin capital V with dot above]O2; -4.6%, -12.0%, and +2.8% for [latin capital V with dot above]CO2; and -0.7%, -4.7%, and +3.3% for [latin capital V with dot above]E. During the human trial, no significant difference was shown between [latin capital V with dot above]O2 measured by VmaxSTTM and by DBM at any stage of exercise. The mean difference and the upper and lower limits of agreement between the VmaxSTTM and the DBM measurements were -0.5%, -14.3%, and +13.3% for [latin capital V with dot above]O2; -6.3%, -20.9%, and +8.3% for [latin capital V with dot above]CO2; and -9.9%, -25.5%, and +5.7% for [latin capital V with dot above]E....