End Systolic Pressure Changes Following An Acute Bout Of Exercise In African Americans And Caucasians

INTRODUCTION: End systolic pressure (ESP) is related to myocardial effort and affects passive filling during diastole, thus also affecting stroke volume. ESP is usually derived from the prediction equation 0.9 x systolic blood pressure. However, it is unknown whether this equation is accurate following perturbations such as exercise. African Americans (AA) have a greater prevalence and are predisposed to hypertension at an early age as compared to Caucasians (C). Hence, ESP could also be affected by ethnicity. PURPOSE: The purpose of this study was to compare measured ESP between African Americans and Caucasians at rest, 15 minutes post and 30 minutes post maximal aerobic exercise bout. The secondary purpose was to compare the values from the prediction equation to the measured values. METHODS: 56 subjects (24 AA and 32 C) underwent an acute progressive maximal bout of exercise on a cycle ergometer. ESP was obtained by applanation tonometry (Sphygmacor) at rest, 15 minutes post and 30 minutes post exercise. Bland-Altman was plotted individually for the prediction equation with the measured ESP. RESULTS: ESP was not different at rest between groups (AA=93 ± 10 mmHg, C= 92 ± 10 mmHg). There was a significant (p<0.05) interaction in the ESP response between Caucasians (92 to 84 to 84 mmHg) and African Americans (93 to 91 to 90 mmHg). Significantly decreased ESP was only observed in Caucasians following exercise, compared to rest. Interestingly, the prediction equation overpredicted resting ESP values (110 ± 10 mmHg vs 92 ±10 mmHg) and none of the predicted values changed significantly from rest following exercise (110 to 109 to 107 mmHg), without any interaction with ethnicity. CONCLUSIONS: The data indicates that Caucasians exhibited a greater decrease in ESP compared to African Americans following exercise. The prediction equation did not accurately predict resting or post exercise ESP, in fact the prediction became less accurate following exercise. Our data suggest that predicted ESP is inaccurate in this young healthy population. Furthermore, African Americans did not decrease ESP following exercise, suggesting that myocardial afterload is greater in this population during exercise recovery. Supported by: NHLBI 1R01HL093249-01A1