Gender differences in the decline in aerobic capacity and its physiological determinants during the later decades of life

1 Section of Applied Physiology, Division of Geriatrics and Nutritional Sciences, and 2 Cardiovascular Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri Submitted 4 November 2005 ; accepted in final form 15 February 2006 We investigated the hemodynamic determinants of the age-associated decline in maximal oxygen uptake ( O 2 max ) and the influence of gender on the decline in O 2 max and its determinants in old and very old men and women. Sedentary, 60- to 92-yr-old women ( n = 71) and men ( n = 29), with no evidence of cardiovascular disease, underwent maximal treadmill exercise tests during which O 2 max and maximal cardiac output ( max ) were determined. O 2 max and age were inversely related in both women (–23 ± 2 ml·min –1 ·yr –1 ; P < 0.0001) and men (–57 ± 5 ml·min –1 ·yr –1 ; P < 0.0001). The absolute slope of the O 2 max vs. age relationship was twofold steeper in men than in women ( P < 0.0001). max was also inversely related to age in a gender-specific manner (women = –87 ± 25 ml·min –1 ·yr –1 , P = 0.0009; men = –215 ± 50 ml·min –1 ·yr –1 , P = 0.0002; P = 0.01 women vs. men). Age-related changes in maximal exercise arteriovenous oxygen content difference (a-vD O 2 ) were marginally different ( P = 0.08) between women (–0.12 ± 0.03 ml·dl –1 ·yr –1 , P = 0.0003) and men (–0.22 ± 0.04 ml·dl –1 ·yr –1 , P < 0.0001). Age-associated decreases in max and a-vD O 2 contributed equally to the declines in O 2 max in both men and women. In the later stages of life, O 2 max , max , and a-vD O 2 decrease with age more rapidly in older men than they do in older women. As a result, the gender differences dissipate in the later decades of life. Declines in max and a-vD O 2 contribute equally to the age-related decrease in O 2 max in men and women. exercise; cardiac output; hemodynamics; maximal oxygen uptake; aging Address for reprint requests and other correspondence: A. A. Ehsani, Campus Box 8113, 4566 Scott Ave., St. Louis, MO 63110 (e-mail: aehsani{at}im.wustl.edu )