Forearm vascular conductance responses to rhythmic handgrip in young African American compared with Caucasian American women

Abstract

Non-Hispanic African American (AA) individuals have a disproportionately high prevalence, and mortality rate of cardiovascular disease (CVD) compared to other populations. Previous studies have demonstrated that even young, healthy AA individuals have blunted flow-mediated dilation, attenuated vasodilatory responses to pharmacological infusions and rhythmic handgrip exercise (RHG), as well as higher arterial stiffness and exaggerated peripheral vasoconstriction to isometric handgrip exercise and other non-exercise-stimuli compared to Caucasian-American (CA) individuals. These studies indicate that vascular alterations occur early on in life of AA individuals, potentially contributing to elevated risk of CVD in this racial group. However, these racial disparities in vascular function have almost exclusively been studied in men. Herein, we tested the hypothesis that, similar to young AA men, young AA women will exhibit an attenuated increase in forearm blood flow (FBF) and forearm vascular conductance (FVC) during rhythmic handgrip exercise (RHG) compared to age-matched CA women. Forearm blood flow (FBF; duplex Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured in young CA (n = 5) and AA (n = 5) women during rhythmic handgrip exercise performed at three workloads (15%, 30%, and 45% of maximal voluntary contraction (MVC)). FVC was calculated as FBF/MAP. Baseline FBF (CA: 66.0 ± 12.8 and AA: 61.6 ± 12.2 ml/min; mean ± SD, p = 0.30); FVC (CA: 0.8 ± 0.2 and AA: 0.7 ± 0.2 ml/min/mmHg; p = 0.16), MAP (CA: 82 ± 11 and AA: 88 ± 4 mmHg; p = 0.28), and MVCs (CA: 50 ± 4 and AA: 52 ± 5 kg; p = 0.35) were similar between the groups. Both groups exhibited intensity-dependent increases in FBF and FVC; however, contrary to our hypothesis, there were no race difference (mixed-model two-way ANOVA; FVC: race effect p = 0.18, intensity effect p < 0.0001, interaction p = 0.48). For instance, in response to RHG at 45%, CA had 384 ± 112% increase in FBF from baseline and AA had 499 ± 153% increase. Increase in FVC from baseline was 198 ± 76% for CA women and 314 ± 151% for AA women. MAP did not differ between the groups (e.g., ΔMAP at 45%; CA: 13 ± 11 vs AA: 9 ± 5, p = 0.41). These preliminary data suggest that the hyperemic response to rhythmic handgrip exercise in young African American women are similar to age-matched Caucasian-American women. Supported byKinesiology and Health Education UT Austin Start-up Account 19-2635-91. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.