title: Reference Values for Peak Exercise Cardiac Output in Healthy Individuals.
abstract: Cardiac output (Q˙) is a key parameter in the assessment of cardiac function, its measurement being crucial for the diagnosis, treatment, and prognostic evaluation of all heart diseases. Until recently, Q˙ determination at peak exercise has been possible through invasive methods, so that normal values were obtained in studies based on small populations.
  
  
  
  Nowadays, peak Q˙ can be measured noninvasively by means of the inert gas rebreathing (IGR) technique. The present study was undertaken to provide reference values for peak Q˙ in the normal general population and to obtain a formula able to estimate peak exercise Q˙ from measured peak oxygen uptake (V˙o2).
  
  
  
  We studied 500 normal subjects (age, 44.9 ± 1.5 years; range, 18-77 years; 260 men, 240 women) who underwent a maximal cardiopulmonary exercise test with peak Q˙ measurement by IGR. In the overall study sample, peak Q˙ was 13.2 ± 3.5 L/min (men, 15.3 ± 3.3 L/min; women, 11.0 ± 2.0 L/min; P < .001) and peak V˙o2was 95% ± 18% of the maximum predicted value (men, 95% ± 19%; women, 95% ± 18%). Peak V˙o2and peak Q˙ progressively decreased with age (R2, 0.082; P < .001; and R2, 0.144; P < .001, respectively). The V˙o2-derived formula to measure Q˙ at peak exercise was (4.4 × peak V˙o2) + 4.3 in the overall study cohort, (4.3 × peak V˙o2) + 4.5 in men, and (4.9 × peak V˙o2) + 3.6 in women.
  
  
  
  The simultaneous measurement of Q˙ and V˙o2at peak exercise in a large sample of healthy subjects provided an equation to predict peak Q˙ from peak V˙o2values.
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy; Cardiovascular Section, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy. Electronic address: piergiuseppe.agostoni@unimi.it.
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Agostoni
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Vignati
authors.affiliation: Division of Cardiology, Cardiovascular Department, Azienda Sanitaria Universitaria Integrata and University of Trieste, Trieste, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Gentile
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Costanza
authors.initials: C
authors.lastname: Boiti
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Farina
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Salvioni
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Mapelli
authors.affiliation: Department of Clinical and Molecular Medicine, "Sapienza" Università degli Studi di Roma, Rome, Italy.
authors.forename: Damiano
authors.initials: D
authors.lastname: Magrì
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy; IRCCS SDN Istituto di Ricerca, Naples, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Paolillo
authors.affiliation: Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Corrieri
authors.affiliation: Division of Cardiology, Cardiovascular Department, Azienda Sanitaria Universitaria Integrata and University of Trieste, Trieste, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Sinagra
authors.affiliation: Unità Operativa Cardiologia Riabilitativa, MultiMedica IRCCS, Milan, Italy.
authors.forename: Gaia
authors.initials: G
authors.lastname: Cattadori
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002302:Cardiac Output / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D012016:Reference Values; D055815:Young Adult
keywords: cardiac output; exercise; oxygen consumption