Factors limiting maximal O2 consumption: effects of acute changes in ventilation.

摘要: The response of the O2 transport system to acute changes in alveolar ventilation (VA) was analysed. fractional limitations maximal consumption (VO2max) imposed by lungs (ventilation, FV, and lung-blood transfer, FL), cardiovascular (FQ), peripheral diffusion (Fp) were calculated according a multifactorial model. A reference set data, describing status at exercise normoxia used. effects VA on VO2max assessed assumption constant flow mixed venous blood (QVO2). data after given independent an iterative procedure, until value compatible with QVO2 found, PIO2 values 150 (normoxia), 130, 110 90 Torr. less than expected assuming linear system, because flatness dissociation curve around normoxic PO2. This affected resistance flow, its counterbalanced induced VA. phenomenon reversed hypoxia, as steep part approached. resulted follows: FV FL provided between 5 12%, FQ 59 78%, Fp 13 19% overall limitation. In increased decreased. At = Torr, when halved, FL, amounted 0.35, 0.31, 0.20 0.14, respectively.