Sex-specific influence of aging on exercising leg blood flow

Our previous work suggests that healthy human aging is associated with sex-specific differences in leg vascular responses during large muscle mass exercise (2-legged cycling) (Proctor DN, Parker BA. Microcirculation 13: 315–327, 2006). The present study determined whether age × sex interactions in exercising leg hemodynamics persist during small muscle mass exercise that is not limited by cardiac output. Thirty-one young (20–30 yr; 15 men/16 women) and 31 older (60–79 yr; 13 men/18 women) healthy, normally active adults performed graded single-leg knee extensions to maximal exertion. Femoral artery blood velocity and diameter (Doppler ultrasound), heart rate (ECG), and beat-to-beat arterial blood pressure (mean arterial pressure, radial artery tonometry) were measured during each 3-min work rate (4.8 and 8 W/stage for women and men, respectively). The results (means ± SE) were as follows. Despite reduced resting leg blood flow and vascular conductance, older men exhibited relatively preserved exercising l...