Peripheral and Central Hemodynamic Responses to Rhythmic Handgrip Exercise in Young, Healthy Black Women.

Abstract

Purpose: Non-Hispanic Black (NHB) women in the United States exhibit higher prevalence and mortality rates from cardiovascular diseases compared to non-Hispanic White (NHW) women. Previous studies in NHB men have demonstrated impaired vascular function at rest and during exercise; however, to date, no studies have investigated the hyperemic responses during exercise in NHB women. Therefore, we tested the hypothesis that, compared with NHW women, NHB women would present an attenuated increase in forearm blood flow (FBF) and forearm vascular conductance (FVC) during steady-state rhythmic handgrip exercise.

Methods: FBF (duplex Doppler ultrasound) and central hemodynamics including mean arterial pressure (MAP; finger photoplethysmography) were measured in healthy young NHW (n = 16) and NHB (n = 14) women during rhythmic handgrip exercise performed at 15%, 30% and 45% of maximal voluntary contraction (MVC).

Results: FVC (calculated as FBF/MAP), FBF, and MAP were not different between groups at rest (FVC: 52 ± 13 ml/min/100 mmHg in NHW women vs. 56 ± 14 ml/min/100 mmHg in NHB women; P = 0.43). There was an intensity-dependent increase in FBF and FVC during exercise in both groups, but there was no difference between the groups (e.g., FVC at 45% MVC; NHW: 304 ± 55 ml/min/100 mmHg, NHB: 351 ± 121 ml/min/100 mmHg, interaction P = 0.257). MAP responses during exercise were also not different between groups (e.g., ΔMAP at 45% MVC; NHW: 7 ± 6 mmHg, NHB:8 ± 6 mmHg, P = 0.553). Additionally, all central hemodynamics during exercise, and flow-mediated dilation were comparable between the groups.

Conclusions: Collectively, these findings indicate that the hyperemic responses to rhythmic handgrip exercise are not different between young, healthy NHB and NHW women.