Older women exhibited attenuated hyperemic (40 vs 52 ml/min/W; P=0.02) and vasodilatory responses to single-leg exercise compared with young women, whereas older men had preserved responses.
Cross-Sectional (n=62)
Does aging have a sex-specific effect on exercising leg hemodynamics during small muscle mass exercise in healthy adults?
Healthy aging is associated with attenuated exercising leg hyperemic and vasodilatory responses in women but not in men, suggesting local factors contribute to sex-specific hemodynamic aging.
Absolute Event Rate: 40% vs 52%
p-value: p=0.02
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 x 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 leg hemodynamic responses. Older women, by contrast, exhibited attenuated hyperemic (young: 52 +/- 3 ml.min(-1).W(-1); vs. older: 40 +/- 4 ml.min(-1).W(-1); P = 0.02) and vasodilatory responses (young: 0.56 +/- 0.06 ml.min(-1).mmHg(-1).W(-1) vs. older: 0.37 +/- 0.04 ml.min(-1).mmHg(-1) W(-1); P < 0.01) to exercise compared with young women. Relative (percentage of maximal) work rate comparisons of all groups combined also revealed attenuated vasodilator responses in older women (P < 0.01 for age x sex x work rate interaction). These sex-specific age differences were not abolished by consideration of hemoglobin, quadriceps muscle, muscle recruitment, and mechanical influences on muscle perfusion. Collectively, these findings suggest that local factors contribute to the sex-specific effects of aging on exercising leg hemodynamics in healthy adults.
Parker et al. (Thu,) conducted a cross-sectional in Healthy, normally active adults (n=62). Older age (60-79 yr) vs. Young age (20-30 yr) was evaluated on Hyperemic response to exercise in women (ml.min(-1).W(-1)) (p=0.02). Older women exhibited attenuated hyperemic (40 vs 52 ml/min/W; P=0.02) and vasodilatory responses to single-leg exercise compared with young women, whereas older men had preserved responses.