Abstract
Blood pressure (BP) is a highly variable physiologic trait with short-term and long-term fluctuations within the same individual at different time points. The burden of BP on the cardiovascular (CV) system has been studied in terms of multiple cross-sectional BP measurements at rest, response of BP to stresses, and long-term longitudinal variability of BP. Observations from childhood are available extending into early middle age in the biracial (black-white) population of Bogalusa, Louisiana. Left ventricular mass index was used to illustrate damaging effects on the CV system by both resting BP levels and fluctuations. Long-term BP variability reflecting intermittent and repeated variability was shown to have a greater effect in blacks. The childhood BP response to several stressors was found to be greater in blacks. These observations suggest that, although at rest a greater vagal effect occurs in blacks, they show a greater response when reacting to a stimulus. This, along with aspects such as carbohydrate-insulin metabolism or other biochemical/physiological differences, may account for the greater acceleration of CV atherosclerosis in blacks. The racial contrasts suggest, in part, that effects of lipoproteins may be greater in whites, whereas the effects of excess BP levels and variability of BP and Na(+)-K(+) intake and diet as well as other environmental effects result in more CV damage in blacks. The strong association of hemodynamic measures with anatomic, metabolic, and environmental factors emphasizes the need to begin prevention of risk factors at an early age. Taken together, understanding racial (black-white) contrasts to stress contribute to both prevention and treatment of hypertension, especially for black males.