Racial differences in arterial stiffness after exercise in young men.

BACKGROUND: African-American men have stiffer arteries than white men at rest. We sought to test the hypothesis that reductions in stiffness after aerobic exercise may be attenuated in African-American (AA) men compared with white (W) men.
METHODS: Twenty-four young men (age 22+/-1.0 years; 12 AA and 12 W) underwent measures of central (carotid-femoral) and peripheral (femoral-dorsalis pedis) pulse-wave velocity (PWV) before, 15 min after, and 30 min after a graded maximal aerobic exercise test (EX).
RESULTS: A group effect was detected for central PWV, because AA men had significantly higher resting aortic stiffness compared with W men (P<.05). There was no change in central PWV after EX in either group. A group-by-time interaction was detected for peripheral PWV, because there were significant reductions in W men at 15 min and 30 min after EX, but no change at either time point in AA men (P<.05).
CONCLUSIONS: Our data support previous findings of greater resting central aortic stiffness in young AA versus W men. This difference was not affected by acute EX. This is the first study to note large racial differences in the peripheral arterial response to exercise, consistent with the notion of blunted vasodilatation in response to adrenergic stimulation in AA men.