IMPAIRED ENDOTHELIAL VASODILATOR FUNCTION BUT NOT ARTERIAL STIFFNESS IS ASSOCIATED WITH MAXIMAL EXERCISE BLOOD PRESSURE:

Persons with normal or mildly elevated blood pressure (BP) at rest who have an exaggerated exercise BP are at increased risk to develop worsening hypertension. The mechanisms for this exaggerated rise in exercise BP are largely unknown. We examined the relationship of endothelial vasodilator function and arterial stiffness with exercise BP responses to maximal treadmill exercise in men (n = 47) and women (n = 53) aged 64 ± 6 years with milder forms of hypertension, but who were otherwise healthy. Endothelial vasodilator function was assessed as brachial artery flow-mediated vasodilation (FMD) during reactive hyperemia. Arterial stiffness was assessed as the pulse wave velocity (PWV) using simultaneous tracings of the arterial pulse detected in the carotid and femoral arteries. In men, resting systolic BP (SBP) explained 29\% of the variance (p < 0.0001) in maximal SBP and FMD explained an additional 7\% (p < 0.05). In women, resting SBP was the only independent correlate of maximal SBP, R2 = 0.31 (p < 0.02). FMD was the only independent correlate of the SBP change from rest to maximal in men, R 2 = 0.13, (p < 0.01). FMD was the only independent correlate of pulse pressure (PP) change from rest to maximal in men R 2 = 0.11, (p < 0.03) and in women, R 2 = 0.08, (p < 0.04). Maximal oxygen uptake and PWV did not correlate with exercise BP or PP or the change from rest. No relationship was observed between arterial stiffness and the BP response to maximal exercise, whereas impaired endothelial vasodilator function was identified as a mechanism associated with exercise hypertension. Because an exaggerated exercise BP is a predictor of future resting hypertension, the results raise the possibility that impaired endothelial function may be a risk factor for hypertension.