Exercise Pressor Response in Hispanic Adults with Family History of Hypertension

Family history of hypertension (FHH), being an unmodifiable risk factor, increases probability of developing hypertension and other cardiovascular diseases. The prevalence of hypertension in Hispanic/Latino (H/La) males is 50.3%, while it is 48.9% in non-Hispanic white (NHW) males and 57.5% in non-Hispanic black (NHB) males. Among adolescents aged 8 to 17, H/La youth has the highest incidence of hypertension as compared to all other races. It is evident that young normotensive adults with positive family history of hypertension (+FHH) exhibit exaggerated exercise pressor response. Additionally, a higher sympathetic activity to cold pressor test (CPT) was found in normotensive NHB adults with +FHH. However, the potential effect of +FHH in H/La population remains unexplored. PURPOSE: In this study we investigated the effect of +FHH on the pressor response during exercise and CPT in H/La adults with +FHH and without family history of hypertension (-FHH). METHODS: In 5 H/La adults with +FHH (age = 24 ± 4 mmHg; BMI = 24 ± 3 kg/m2; MVC = 76 ± 9 kg) and 6 H/La adults with -FHH (age = 21 ± 0.4 years; BMI = 24 ± 1 kg/m2; MVC = 82 ± 10 kg), beat-to-beat blood pressure (finger plethysmography) and heart rate (ECG) were measured at rest and during 2 minutes of static handgrip exercise performed at 30% and 40% of their maximum voluntary contraction (MVC). Muscle metaboreflex was isolated by post exercise ischemia (PEI; supra-systolic cuff (220 mmHg) inflation on the exercising arm) for 2 minutes and 15 seconds. We further investigated the pressor response to CPT, a generalized sympatho-excitatory stimulus, by putting the hand in ice water for 2 minutes. RESULTS: Resting mean arterial pressure (MAP) was not different between groups (+FHH = 78 ± 6 mmHg; -FHH = 79 ± 8 mmHg; p= 0.9). The exercise pressor response at 30% MVC (+FHH = 26 ± 7mmHg; -FHH = 27 ± 8 mmHg; p = 0.9) and 40% (+FHH = 46 ± 8 mmHg; -FHH = 37 ± 13 mmHg; p = 0.3) of MVC static handgrip were not different statistically between the two groups. However, H/La adults with +FHH indicated a trend for augmented pressor response during PEI following handgrip exercise at 40% of MVC (+FHH = 46 ± 4 mmHg; -FHH = 33 ± 10; p = 0.07). The cold pressor response was not different between the two groups (+FHH = 31 ± 6 mmHg; -FHH = 23 ± 15 mmHg; p = 0.36). CONCLUSION: Our preliminary data suggest that Hispanic adults with family history of hypertension exhibit augmented activation of muscle metaboreflex

Influence of Family History of Hypertension on Vascular Function in Young Healthy Black Women

Compared to all other racial groups, non-Hispanic Black (NHB) women have the highest prevalence of hypertension (58.4%) in the United States and experience a two-fold higher mortality from hypertension-related causes. Individuals with a positive family history of hypertension (+FHH) have been shown to exhibit blunted vascular function in response to 5-minute ischemia; however, whether the impact of positive family history of hypertension (+FHH) results in a greater attenuation of vascular function in healthy NHB women remains unknown. PURPOSE: Herein, we tested the hypothesis that young NHB women with +FHH will elicit attenuated increases in forearm blood flow (FBF) and forearm vascular conductance (FVC) during rhythmic handgrip exercise (RHG) compared to age- and weight-matched NHB women without a family history of hypertension (-FHH). METHODS: We studied 14 young normotensive women (+FHH=7) [Age (-FFH: 19 ± 1; and +FHH: 19 ± 1yr; mean ± SD, p = 0.61); BMI (-FFH: 24 ± 2; and +FFH: 24 ± 2 kg/m2; p = 0.82)]. FBF (duplex Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured during rhythmic handgrip exercise performed at three workloads (15%, 30%, and 45% of maximal voluntary contraction (MVC)). FVC was calculated as FBF/MAP. RESULTS: Baseline FBF (-FHH: 41.9 ± 14.0 and +FHH: 48.0 ± 7.1 ml/min; p = 0.32), FVC (-FHH: 50.0 ± 15.9 and +FHH: 62.9 ± 10.2 ml/min/100 mmHg; p = 0.10), and MVCs (-FHH: 57 ± 12 and +FHH: 54 ± 7 kg; p = 0.53) were similar between the groups. Both groups exhibited intensity-dependent increases in FBF and FVC; however, contrary to our hypothesis, there were no difference between the groups [mixed-model two-way ANOVA; %Δ FBF (group effect p = 0.50, intensity effect p \u3c 0.001, interaction p = 0.89) and %Δ FVC (group effect p = 0.34, intensity effect p \u3c 0.001, interaction p = 0.92). For instance, in response to RHG at 45%, -FHH had 592 ± 190 % increase in FBF from baseline and +FHH had 624 ± 154 % increase. Changes in MAP were not different between the groups at any intensity (e.g., ΔMAP at 45% MVC in -FHH = 11 ± 9 and +FHH = 6 ± 5, p = 0.30). CONCLUSION: These preliminary data suggest that the hyperemic responses to rhythmic handgrip exercise in normotensive Black women is not influenced by a positive family history of hypertension

Blood Flow and Vascular Conductance Responses to Dynamic Handgrip Exercise in Hispanic American and Non-Hispanic White Women

Hispanic Americans (HA) are the fastest growing ethnic minority in the United States, with disproportionately higher incidence of obesity, hyperlipidemia and type 2 diabetes compared to their non-Hispanic white (NHW) counterparts. As such, the risk of cardiovascular complications is significantly higher in this population, while the underlying mechanisms remain largely unexplored. Alterations in vascular function occur early in cardiovascular diseases and have not been comprehensively studied in the HA population. Previous studies have demonstrated higher flow-mediated dilation (FMD, an index of resting vascular function) in young HA compared to NHW women. However, whether these differences in vasodilation also occur in response to dynamic exercise remains unknown. PURPOSE: We tested the hypothesis that during increasing intensities of rhythmic handgrip exercise, young, healthy HA women would demonstrate greater forearm blood flow and vascular conductance responses compared to age- and weight-matched NHW women. METHODS: Six HA women (20 ± 2 yr; BMI = 21.45 ± 2.2 kg/m2) and 9 NHW women (20 ± 2 yr; BMI = 21.49 ± 2.2 kg/m2) performed rhythmic handgrip exercise for 3 minutes at 15%, 30%, and 45% of their maximum voluntary contraction (MVC). Each exercise bout was separated by at least 10 minutes of rest. Mean arterial pressure (MAP; finger photoplethysmography), heart rate (ECG), and forearm blood flow (FBF; duplex Doppler ultrasound) was measured at rest and during the last minute of rhythmic exercise. Forearm vascular conductance was calculated as FBF/MAP. RESULTS: Baseline FBF (HA: 53.3 ± 7.6 and NHW: 52.4 ± 11.3 ml/min, mean ± SD, p = 0.87), FVC (HA: 0.64 ± 0.09 and NHW: 0.62 ± 0.16 ml/min/mmHg, p = 0.85), MAP (HA: 83.3 ± 3.18 and NHW: 84.75 ± 6.85 mmHg, p = 0.64), and MVC (HA: 53 ± 13 and NHW: 49 ± 6 kg, p = 0.36) were similar between groups. In response to exercise, both groups demonstrated an intensity dependent increase in FBF (%DFBF during 45%: HA= 437± 90% and NHW= 459 ± 162%, p = 0.76) but no significant difference was found between groups (repeated-measures 2-way ANOVA; interaction effect: p = 0.66, intensity effect: p = 0.0001, ethnicity effect: p = 0.73). Similar to FBF, there was no significant difference in FVC responses between groups (%DFVC 45%: HA= 385 ± 110 and NHW= 393 ± 135, p = 0.91). CONCLUSION: Forearm blood flow and vascular conductance responses during increasing intensities of rhythmic handgrip exercise were not different between HA and NHW women