Gender Differences in the Oxygen Transport System During Maximal Exercise in Hypertensive Subjects

• Published in: Chest Vol. 115; no. 3; pp. 788 - 792
• Main Authors: Reybrouck, Tony, Fagard, Robert
• Format: Journal Article
• Language: English
• Published: Northbrook, IL Elsevier Inc 01.03.1999; American College of Chest Physicians
• Subjects: Adult; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Cardiac Output; Cardiology. Vascular system; Catheters; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Exercise; Exercise - physiology; Exercise Test; exercise testing; Female; gas exchange; gender; Gender differences; Heart rate; Hemodynamics; Hemoglobin; Hemoglobins - analysis; Humans; Hypertension; Hypertension - blood; Male; Maximum oxygen consumption; Medical sciences; Middle Aged; Oxygen - blood; Oxygen saturation; Patients; Pulmonary arteries; Sex Characteristics; Statistical analysis; Veins & arteries; Women; cardiac output; (av)o2; exercise testing; R; gender; NS; V˙o2; V˙co2; gas exchange; hypertension; hemodynamics; Physical exercise; Human; Hypertension; Blood gas; Oxygen; Venous blood; Saturation; Sex; Cardiovascular disease; Exploration; Male; Arterial blood; Exercise tolerance test; Female; Transport; Comparative study
• DOI: 10.1378/chest.115.3.788
• ISSN: 0012-3692

To analyze gender differences in the oxygen transport system at peak exercise with particular emphasis on the difference in systemic arteriovenous oxygen extraction and in mixed venous oxygen saturation. Cardiopulmonary graded exercise testing and hemodynamic assessment were performed on a cycle ergometer in 64 hypertensive patients (32 female and 32 male) varying in age from 23 to 64 years. Female and male patients were matched for age and BP. Peak oxygen uptake was significantly lower in women than in men, and when expressed in absolute units (L/min: −39%) and when normalized for body mass (mL/min/kg: −33%) or statistically adjusted for height and weight (−29%). This resulted essentially from a significantly lower cardiac output in women, both when expressed in absolute units and when adjusted for body size. At the peripheral level, female patients had a lower arteriovenous oxygen content difference at peak exercise, which resulted from a lower hemoglobin concentration and the inability to decrease mixed venous oxygen saturation to the same level as in men. The lower peak oxygen uptake of women results from both central and peripheral factors. The significantly higher value for mixed venous oxygen saturation, which contributes to the lower arteriovenous oxygen difference of women, could result from their smaller muscle mass, lower capillary density, and lower oxidative potential.