C‐Reactive Protein Levels and Blood Pressure Loads with Training

Abstract

Blood pressure (BP) load is the percentage of BP readings above a particular threshold within a given period. Elevated BP loads translate to organ exposures to high pressures for greater amounts of time. Because of this, BP load was heralded as a strong predictor of target organ damage (TOD). However, recent evidence has not confirmed its prognostic value above 24 hr ambulatory blood pressure monitoring (ABPM). Although questioned, it is incorporated in AHA ABPM guidelines for children and adolescents. Newer evidence in chronic kidney disease and untreated hypertensives has shown an independent association of BP load with various measures of TOD. Additionally, a marker of systemic inflammation (neutrophil‐to‐lymphocyte ratio) has been shown to correlate with BP load.ObjectiveThis analysis investigated the relationship between classic inflammatory biomarker C‐Reactive Protein (CRP) and debated measure BP Load in a high‐risk population for cardiovascular diseases (CVD).MethodsSedentary, middle‐to‐older age African Americans free of disease underwent aerobic exercise training (AEXT) 3x/week for 24 weeks. Intensity targets progressed to sustain 60% VO2 max. Because of the strong relationship between BMI and BP, participants were required to maintain a constant weight. ABPM was conducted before and after training, and BP loads determined. Fasted blood draws were utilized at these times to measure circulating CRP and categorize future CVD risks based on baseline CRP levels. Slightly less conservative thresholds for BP readings were used because of this known high‐risk population.ResultsWith training, daytime SBP and DBP loads decreased for those only in the low risk CRP group (p=.047 and p=.036, respectively). Nighttime values, however, did not change for either CRP group with training. For daytime values at baseline and final, there was no difference in SBP load (>124 mmHg) for those classified as at low (<1mg/L), average (1–3mg/L) or high (>3mg/L) risk for CVD based on CRP levels. When a more conservative threshold was utilized (SBP >139 mmHg) there was a difference between CRP groups after training (p<.05). There was a similar trend for DBP load (DBP>74 mmHg), with a difference appearing after training (p<.05). Nighttime DBP load did not differ between groups either before or after training. SBP load, however, differed between CRP groups at baseline when a more (>119 mmHg, p<.05), but not less (>104 mmHg) conservative threshold was used. Groups after training showed no SBP load difference.ConclusionsCRP levels may contribute to BP loads and resultant TOD. These may be a specific indicator of the response to AEXT, especially in those considered low‐risk. Because nighttime BP load did not change with training in either category, but daytime values did decrease, the reasons for this need to be further examined. It is possible that a different stimulus may be necessary to cause changes in nighttime values. This is especially important since recent evidence has shown nighttime values to be a greater indicator of clinical events and cardiovascular outcomes than daytime BP values. Additionally, BP load thresholds may need to be adjusted for various populations. Future studies are needed to confirm the independent effect of BP load in this high‐risk population, and its relationship to inflammation.Support or Funding InformationNIH Grant #R01 HL085497‐01A1 Systolic (>139 mmHg) and Diastolic (>74 mmHg) Blood Pressure load decreased after training in low‐risk subjects. SBP Load showed between group differences only after, but not before training.* p<.05 within groups. # p<.05 between groupsimageSystolic (>139 mmHg) and Diastolic (>74 mmHg) Blood Pressure load decreased after training in low‐risk subjects. SBP Load showed between group differences only after, but not before training.* p<.05 within groups. # p<.05 between groups Neither Systolic (>104 mmHg) nor Diastolic (>64 mmHg) Blood Pressure load decreased after training for subjects. SBP (>119) Load showed between group differences before, but not after training. # p<.05 between groupsimageNeither Systolic (>104 mmHg) nor Diastolic (>64 mmHg) Blood Pressure load decreased after training for subjects. SBP (>119) Load showed between group differences before, but not after training. # p<.05 between groupsThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.