EFFECTS OF AGE AND AEROBIC CAPACITY ON ARTERIAL STIFFNESS IN HEALTHY-ADULTS

Background. It has been well established that arterial stiffness, mani fest as an increase in arterial pulse wave velocity or late systolic a mplification of the carotid artery pressure pulse, increases with age. However, the populations studied in prior investigations were not rig orously screened to exclude clinical hypertension, occult coronary dis ease, or diabetes. Furthermore, it is unknown whether exercise capacit y or chronic physical endurance training affects the age-associated in crease in arterial stiffness. Methods and Results. Carotid arterial pr essure pulse augmentation index (AGI), using applanation tonometry, an d aortic pulse wave velocity (APWV) were measured in 146 male and fema le volunteers 21 to % years old from the Baltimore Longitudinal Study of Aging, who were rigorously screened to exclude clinical and occult cardiovascular disease. Aerobic capacity was determined in all individ uals by measurement of maximal oxygen consumption (VO2max) during trea dmill exercise. In this healthy, largely sedentary cohort, the arteria l stiffness indexes AGI and APWV increased approximately fivefold and twofold, respectively, across the age span in both men and women, desp ite only a 14% increase in systolic blood pressure (SBP). These age-as sociated increases in AGI and APWV were of a similar magnitude to thos e in prior studies of less rigorously screened populations. Both AGI a nd APWV varied inversely with VO2max, and this relationship, at least for AGI, was independent of age. In endurance trained male athletes, 5 4 to 75 years old (VO2max=44+/-3 mL . kg-1 . min-1), the arterial stif fness indexes were significantly reduced relative to their sedentary a ge peers (AGI, 36% lower, APWV, 26% lower) despite similar blood press ures. Conclusions. Even in normotensive, rigorously screened volunteer s in whom SBP increased an average of only 14% between ages 20 and 90 years, major age-associated increases of arterial stiffness occur. Hig her physical conditioning status, indexed by VO2max, was associated wi th reduced arterial stiffness, both within this predominantly sedentar y population and in endurance trained older men relative to their less active age peers. These findings suggest that interventions to improv e aerobic capacity may mitigate the stiffening of the arterial tree th at accompanies normative aging.