The Q˙-V˙O2 diagram: an analytical interpretation of oxygen transport in arterial blood during exercise in humans.
A new analysis of the relationship between cardiac output (Q˙) and oxygen consumption V˙O2 is presented (Q˙-V˙O2 diagram). Data from different sources in the literature have been used for validation in three conditions: exercise and rest in normoxia, and exercise in hypoxia. The effects of changes in arterial oxygen concentration CaO2 on Q˙ are discussed, as well as the effects of predominant sympathetic or vagal stimulation. Differences appear depending on whether CaO2 is varied by means of changes in blood haemoglobin concentration or changes in arterial oxygen saturation. The present Q˙-V˙O2 diagram allows comprehensive description of oxygen transport in exercising humans; it expands applicability of the historical Q˙-V˙O2 relationship to include CaO2 variations; it opens new pathways for understanding underlying mechanisms; it allows computation of Q˙ from CaO2 and V˙O2 measurements, when Q˙ cannot be measured.
Département de Neurosciences Fondamentales, Université de Genève, 1 Rue Michel Servet, CH-1211 Genève 4, Switzerland.
Alessandra
A
Adami
Dipartimento di Scienze Cliniche e Sperimentali, Università di Brescia, Viale Europa 11, I-25123 Brescia, Italy.
Nazzareno
N
Fagoni
Département de Neurosciences Fondamentales, Université de Genève, 1 Rue Michel Servet, CH-1211 Genève 4, Switzerland; Dipartimento di Scienze Cliniche e Sperimentali, Università di Brescia, Viale Europa 11, I-25123 Brescia, Italy. Electronic address: guido.ferretti@unige.ch.
Guido
G
Ferretti
D000465:Algorithms; D001158:Arteries / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D008955:Models, Cardiovascular; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D012146:Rest
D010100:Oxygen
Arterial oxygen concentration; Cardiac output; Hypoxia; Oxygen uptake