Sex Differences In Post-exercise Wasted Pressure Effort In Healthy Young, But Not Older, Adults

We have previously shown that wasted pressure effort (WPE), the pressure needed to overcome the effect of wave reflections during systole, is reduced following an acute bout of aerobic exercise in young adults. Research has shown that young women have a more favorable hemodynamic response after an acute bout of aerobic exercise compared to young men. These differences may be due to the cardioprotective effects of female sex hormones in premenopausal women that are lost following menopause. It is not known if WPE is differentially affected by acute exercise in men and women and whether age influences WPE in response to acute exercise. PURPOSE: This retrospective analysis tested the hypothesis that young women experience a greater reduction in WPE compared to young men following an acute bout of aerobic exercise, whereas any reduction in WPE does not differ between older women and men. METHODS: In 19 young adults (10 women, 9 men, 18 - 40 years) and 16 older adults (8 women, 8 men, 60 - 75 years) aortic pressure waveforms were derived from radial pulse waves acquired via high-fidelity applanation tonometry at baseline and 30 min after a 15-min bout of aerobic exercise on a supine cycle ergometer. Concurrently, left ventricular outflow tract flow velocities were acquired via Doppler echocardiography. Pressure-flow analyses were performed and indices of wave reflection as well as pressure time integrals (WPE) were computed. RESULTS: Baseline WPE trended to be different between young women and men (1908 ± 814 vs. 1348 ± 478 mmHg•ms, p = 0.09) and was not different between older women and men (5780 ± 2268 vs. 5457 ± 2293 mmHg•ms, p = 0.78). The reduction in WPE was greater in young women compared to young men at 30 min post-exercise (Δ-827 ± 678 vs. Δ-212 ± 566 mmHg•ms, p = 0.048). In contrast, the reduction in WPE did not differ between older women and older men at 30 min post-exercise (Δ-2378 ± 1636 vs. Δ-2178 ± 1336 mmHg•ms, p = 0.79). CONCLUSION: There were sex differences in the reduction of WPE after an acute bout of submaximal aerobic exercise in young adults, but not in older adults. These preliminary results suggest the loss of cardioprotective sex hormones with menopause may have contributed to the loss of sex differences in post-exercise WPE responses with aging.