Ventilatory Thresholds during a Graded Exercise Test

Publisher Website
Google Scholar
Abstract
Selected respiratory gas exchange variables were monitored. When 38 healthy male volunteers were administered, a graded exercise test. In each case, 2 distinct ventilatory thresholds were observed. The 1st threshold was detected by the power output at which the .ovrhdot.VE/.ovrhdot.VO2 [volume of O2 produced] ratio and FEO2 [O2 in expired air] reached a minimum. The mathematical relationship between these 2 variables was such that at power outputs above this threshold, hyperventilation with respect to O2 consumption had to occur. The 2nd threshold was detected by the power output at which the .ovrhdot.VE/.ovrhdot.VCO2 volume of CO2 produced ratio reached a minimum and the FECO2 [CO2 in expired air] reached a maximum. These 2 variables were related in a manner such that at power outputs above this threshold, hyperventilation with respect to CO2 production had to occur.