Objective: The effects of exercise training on nocturnal blood pressure (BP) dipping status remain unclear. African Americans have the highest prevalence of nondippers compared with other racial/ethnic populations. In this 6-month study we tested the hypothesis that long-term aerobic exercise training would increase the levels of nocturnal BP dipping in African American nondippers.
Methods and results: We recruited African Americans who were nondiabetic, nonsmoking, and free from cardiovascular and renal disease. For this analysis, only African Americans with a nondipping profile, defined as those with the absence of a nocturnal decline in systolic or diastolic BP (<10% of daytime values), which was determined by ambulatory BP monitoring, were chosen. A pre-post design was used, with baseline and final evaluation including office blood pressure measurement, 24-h ambulatory blood pressure monitoring, fasted blood sampling, and graded exercise testing. Participants engaged in 6 months of supervised aerobic exercise training (AEXT). Following the AEXT intervention, there were significant increases in systolic BP dipping (baseline: 5.8±3.9% vs. final: 9.4±6.1%, P=0.0055) and pulse pressure dipping (baseline: -3.1±6.6% vs. final: 5.0±12.8%, P=0.0109). Of the 18 participants with a nondipping profile at baseline, eight were nonclassified as nondippers after the AEXT intervention. There were no significant changes in office systolic BP/diastolic BP values following the AEXT intervention.
Conclusion: This study suggests that the nondipping pattern of ambulatory BP can be improved by chronic AEXT in African American nondippers, regardless of a change in the 24-h average BP. This finding may be clinically important because of the target organ implication of nondipping nocturnal BP.