Abstract 1536: Sex Specific Effects of Habitual Aerobic Exercise on Brachial Artery Flow-Mediated Dilation in Middle-Aged and Older Adults
Background: Brachial artery endothelium-dependent dilation (flow-mediated dilation, FMD) is impaired with aging and is associated with increased risk for cardiovascular disease (CVD). Interventions that improve brachial artery FMD may help prevent age-related CVD. The purpose of this study was to determine if regular aerobic exercise increases brachial artery FMD in healthy middle-aged/older (ma/o) men and postmenopausal women.
Methods: In a randomized controlled prospective study, non-obese (body mass index <30 kg/m2) ma/o previously sedentary adults (n=36, age 55–79 years) without CVD were studied before and after 8-weeks of vigorous daily walking (n=26, age 63±1 yrs) or non-exercise control (n=10, age 60±1 yrs). In a cross-sectional analysis, healthy ma/o sedentary (n=102, age 62±1 yrs) and endurance exercise-trained (n=65, age 62±1 yrs) men and postmenopausal women were studied.
Results: Daily vigorous walking (~6 days/week, ~50 min/day, ~70% maximal heart rate) increased treadmill exercise time by ~20% in both ma/o men (n=11) and postmenopausal women (n=15) without changing body composition or circulating lipid, metabolic, inflammatory, and vasoactive factors. Brachial FMD increased > 50% in the ma/o men (4.6±0.6 vs. 7.1±0.6%, P<0.01), but did not change in the postmenopausal women (5.1±0.8 vs. 5.4±0.7%, P=0.50). No changes occurred in the non-exercising controls. In the cross-sectional analysis, brachial artery FMD was ~ 50% greater in endurance exercise-trained (n=45) than sedentary (n=60) ma/o men (6.4±0.4 vs. 4.3±0.3 %, P<0.001), whereas there were no differences in exercise-trained (n=20) compared with sedentary (n=42) postmenopausal women (5.3±0.7 vs. 5.6±0.5 %, P=0.70). Brachial artery diameter and endothelium-independent dilation were unaffected by the exercise intervention and did not differ in endurance exercise-trained and sedentary groups.
Conclusions: Regular aerobic exercise is consistently associated with enhanced brachial artery FMD in ma/o men, but not in postmenopausal women. Postmenopausal women without CVD may be less responsive to habitual aerobic exercise than ma/o men.
Supported by NIH awards AG013038, AG006537, AG022241, AG015897, AG031141, AG000279, RR00051, AG031617 and AHA award 0715735Z.
This research has received full or partial funding support from the American Heart Association, Pacific/Mountain Affiliate (Alaska, Arizona, Colorado, Hawaii, Idaho, Montana, Oregon, Washington & Wyoming).