Hemodynamic responses to exercise in white coat hypertension

White coat hypertension, defined as elevated clinic blood pressure readings recorded in the presence of normal ambulatory pressures, is a common finding in the mildly hypertensive population. The diagnosis is usually made using 24-hour ambulatory blood pressure monitoring during a period of irregularly occurring stress and activity (i.e. regular business day). The hemodynamic responses to exercise, a controlled physiologic stressor, measured in individuals with white coat hypertension are not well known and whether any of their responses differ from normotensive or sustained hypertensive individuals has not been determined.

This study compared the hemodynamic responses (i.e blood pressure, forearm blood flow and vascular resistance) to a submaximal exercise test on a dual arm-leg ergometer and biochemical markers of hypertension (i.e. Ca^2+-ATPase and erythrocyte intracellular Ca^2+-)in groups of normotensive (n=11) and white coat hypertensive (n=6) subjects. Forearm blood flow and vascular resistance was measured using bioelectric impedance. The white coat hypertensive group differed significantly only in their absolute rise in systolic and mean arterial blood pressure during the exercise test.

Therefore, the subjects with white coat hypertension differed in only several blood pressure responses to exercise and were similar to normotensives in several other hemodynamic measurements and biochemical markers for hypertension. Whether these findings indicate that these individuals are pre-hypertensive, have underlying hypertension not detected by monitoring or laboratory evaluation, are on a continuum of responses between normotensive and hypertensive, or are just normotensive with an exaggerated response to specific settings or stressors requires further investigation. Additional differences in the hemodynamic responses to exercise in sustained hypertensive individuals would form the basis for a simple, office-based exercise stress which could be used to discriminate between the various groups of hypertensive patients.