Sex differences in forearm blood flow and vascular conductance responses to rhythmic handgrip exercise in young, healthy Hispanic/Latino adults
Authors: Perez Justo , Liu Randy , Dalve Ashlesha , Nyarko Ruby , Joergensen Ethan , Dombroski Lindsay , Fatahimeiabadi Zahra 
Published: May 2024

Hispanic individuals represent the largest ethnic minority in the United States and are projected to make up one-third of the U.S. population by 2060. Compared to non-Hispanic White (NHW) individuals, Hispanic adults exhibit a significantly higher prevalence of type 2 diabetes (17.9% in Hispanic men vs. 11.5% in NHW men and 14.6% in Hispanic women compared to 7.7% in NHW women). Consequently, Hispanic adults also experience a higher prevalence of other microvascular complications such as neuropathy, retinopathy, and nephropathy leading to end stage renal disease. The underlying mechanisms for this disproportionately high incidence of cardiovascular complications in Hispanic population remains largely unexamined. Previous studies indicate that vascular alterations may manifest early on in life in populations with high cardiovascular disease risk. To date, no study has investigated the differences in vascular function between healthy Hispanic men and women during exercise. Therefore, we tested the hypothesis that Hispanic women (HW) would exhibit greater relative increases in forearm blood flow (FBF) and vascular conductance (FVC) during rhythmic handgrip exercise compared to age-matched Hispanic men (HM). FBF (duplex Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured in 20 young, healthy Hispanic individuals (9 men, 11 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 MAP (HM: 84 ± 5, HW: 85 ± 6 mmHg; p = 0.68) were similar between groups while baseline FBF (HM: 79.23 ± 21.43 and HW: 50.17 ± 28.33 ml/min; mean ± SD, p =0.02); FVC (HM: 0.95 ± 0.27 and HW: 0.60 ± 0.36 ml/min/mmHg; p =0.03); and MVCs (HM: 73.63 ± 18.14 and HW: 52.20 ± 10.73 kg; p < 0.001) were different between Hispanic men and women. Both groups exhibited intensity-dependent increases in FBF and FVC, [(mixed-model two-way ANOVA; %Δ FBF: sex effect p = 0.094, intensity effect p < 0.001, interaction p = 0.247) and (%Δ FVC: sex effect p = 0.032, intensity effect p < 0.001, interaction p = 0.14)]. For example, in response to 45% rhythmic hand grip intensity, there were no differences between Hispanic men and women, %Δ FBF (HM: 465.57 ± 98, HW: 527.27 ± 153.20; p = 0.32) and %Δ FVC (HM: 385.22 ± 65.32, HW: 455.90 ± 132.98; p = 0.17). Change in MAP from baseline to 45% rhythmic handgrip was similar between both groups ( p = 0.67). These preliminary data suggest that Hispanic men and women have similar hyperemic responses to rhythmic handgrip exercise at increasing intensities. Supported by Kinesiology and Health Education UT Austin Start-up Account 19-2635-91. This is the full abstract presented at the American Physiology Summit 2024 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.