Effects Of "Life-long" Exercise Training On Arterial Stiffness In The Elderly

Abstract

BACKGROUND: It is well known that human arteries become stiffer with sedentary aging. Conversely, studies by us and others have revealed that Masters athletes (Age>65) who have been training 6-7 sessions/wk throughout their adults lives maintain youthful aortic compliance. Although previous findings support the beneficial effects of exercise training on arterial compliance in the elderly, it is still unknown how lower doses of "life-long" exercise training ameliorate arterial compliance. METHODS: We recruited senior adults (Age>65) with different life-long exercise doses from the Aerobic Center Longitudinal Study, in which patterns of physical activity have been measured for >25 yrs; 1) sedentary seniors (Q1: no regular exercise, N=7), 2) mild-active seniors (Q2: Exercise; 2-3 times/wk, N=3), 3) moderate-active seniors (Q3: Exercise; 4-5 times/wk, N=7), and 4) Masters athletes (Q4: Exercise; 6-7 times/wk, N=13). Central aortic and peripheral arterial compliance were estimated by central (carotid-femoral) and peripheral (carotid-radial) pulse wave velocity (PWV), respectively. Common carotid arterial compliance was estimated by cross-sectional area changes of systolic and diastolic phases (Sono-CT), and corresponding systolic and diastolic blood pressures with beta-stiffness index. RESULTS: Central PWV was significantly slower in seniors who trained 2-3, 4-5 or 6-7 times per week (Q2, Q3, and Q4) than in sedentary seniors (Q1), indicating that even 2-3 times per week exercise training has beneficial effects on aortic compliance. Interestingly, central PWV was not significantly different among Q2, Q3 and Q4, suggesting that this beneficial effect could plateau at small doses of exercise training. Similarly, the beta stiffness index of the common carotid artery was lower (more compliant) in Q2, Q3, and Q4 than in Q1, and was not different among Q2, Q3 and Q4. Peripheral PWV was not significantly different among all groups, suggesting limited effects of exercise training on upper limb peripheral arterial compliance. CONCLUSIONS: It appears that 2-3 times per week of "life-long" regular exercise training provides similar beneficial effects on arterial compliance as more vigorous exercise regimens. Supported by the NIH grant AG17479-05 and the NSBRI Postdoctoral Fellowship grant PR01101.