Exaggerated Systolic Blood Pressure Response after Unaccustomed High‐intensity Interval Exercise is independently related to Decreased Small Arterial Elasticity in Normotensive African American Women
Authors: Carter Stephen J. , Goldsby TaShauna U. , Fisher Gordon , Plaisance Eric P. , Gower Barbara A. , Glasser Stephen P. , Hunter Gary R. 
Published: November 2023

PurposeAerobic exercise is known to transiently lower blood pressure and improve arterial function. However, limited research has evaluated blood pressure and small arterial elasticity (SAE), an index of endothelial function, among African American (AA) and European American (EA) women the morning after (≈22 hours later) acute bouts of moderate‐intensity continuous (MIC) and high‐intensity interval (HII) exercise matched for total work. Since hypertension is more prevalent among AAs compared to EAs, it is of clinical relevance to determine optimal exercise strategies for cardiovascular health. Due to potential greater gradients of shear stress, it was hypothesized that HII exercise would elicit a greater reduction in resting systolic blood pressure (SBP) compared to MIC exercise independent of race.MethodsTwenty‐two, premenopausal AA (n = 11) and EA (n = 11) women had their resting blood pressure and SAE measured by local pulse contour analysis at 4 time points following overnight stays in a room calorimeter: 1) at baseline, 2) after 16 weeks of aerobic training [3x/wk for 40 min at 70% peak VO2], as well as, 3) ≈22 hours after MIC exercise at 50% peak VO2, and 4) ≈22 hours following HII exercise at 84% peak VO2. During the room calorimeter stay, energy intake was adjusted to insure energy balance and to isolate the exercise‐mediated effects on cardiovascular variables. The acute exercise bouts (MIC and HII) were performed on a cycle ergometer at random to reduce an ordering effect. Bivariate correlation analyses were performed to examine relationships in the trained state and the changes (Δ) following acute MIC and HII exercise. Multiple linear regression was used to evaluate the independent effects of race and ΔSAE on ΔSBP.ResultsAfter 16 weeks of aerobic training (TR), resting mean arterial pressure and SAE were not different among races (p > 0.05). However, ≈22 hours after HII exercise a significant increase in SBP (mm Hg) (TR, 121 ± 14 vs. HII, 128 ± 14; p = 0.01) emerged among AAs whereas responses (TR, 116 ± 12 vs. HII, 113 ± 9; p = 0.34) did not differ in EAs. After adjusting for race, ΔSBP after HII exercise was negatively associated (partial r = −0.533; p < 0.01) with ΔSAE. Conversely, among AAs but not EAs, SAE (mL/mmHg ×100) was increased (TR, 7.0 ± 2.3 vs. MIC, 8.3 ± 3.0; p = 0.04) ≈22 hours after an acute bout of MIC exercise.ConclusionsTo our knowledge this is the first study to show that unaccustomed HII exercise results in a prolonged (≈22 hours) elevation in resting SBP among trained AA women. Since participants were not naïve to exercise (having trained for 16 weeks), a possible interpretation is that the AAs may have been overstressed during the HII exercise as the elevated SBP may be indicative of delayed recovery. On the other hand, acute MIC exercise appears to have a favorable effect on SAE among AA women. Future work should consider the mechanistic‐link of the observed outcomes including measures of sympathetic activity.Support or Funding InformationNIH support from the following grants: R01DK049779, P30DK056336, P60DK079626, and UL1RR025777.