Black men with no signs of heart disease experience significantly higher blood pressure during moderate exercise than do white men, a finding that may help researchers understand why black men develop hypertension, according to a small study by the University of North Carolina School of Medicine.

The finding, based on data from a survey sponsored by the National Heart, Lung and Blood Institute, suggests a need for additional study to understand the disparity, according to Lars G. Ekelund, an associate professor of medicine at UNC and the study's principal investigator.

None of the participants showed signs of heart disease before the test. All had normal resting blood presssure and were monitored while walking for six minutes on a treadmill. Black men averaged eight heartbeats per minute faster than white men; systolic blood pressure was seven points higher.

Ekelund said the results suggest that black men may inherit an increased response to stress and a higher resistance to blood flow, leading to the greater risk of hypertension.

Similar reviews of data from 1,159 white women and 113 black women found no differences in blood pressure during exercise.

Ekelund said the findings, published in the May issue of the scientific journal Circulation, require confirmation by a larger study that includes more black men. The original study included more than 2,500 participants but did not specifically seek out black men and included only 83 black males ages 20 to 69.