Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington , Arlington, Texas.
Am J Physiol Heart Circ Physiol. 2018 Nov 1;315(5):H1316-H1321. doi: 10.1152/ajpheart.00387.2018. Epub 2018 Aug 17.
Previous studies have demonstrated that African-American (AA) individuals have heightened vasoconstrictor and reduced vasodilator responses under resting conditions compared with Caucasian-American (CA) individuals. However, potential differences in vascular responses to exercise remain unclear. Therefore, we tested the hypothesis that, compared with CA subjects, AA subjects would present an attenuated increase in forearm vascular conductance (FVC) during rhythmic handgrip exercise. Forearm blood flow (FBF; duplex Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured in healthy young CA ( n = 10) and AA ( n = 10) men during six trials of rhythmic handgrip performed at workloads of 4, 8, 12, 16, 20, and 24 kg. FVC (calculated as FBF/MAP), FBF, and MAP were similar between groups at rest (FVC: 63 ± 7 ml·min·100 mmHg in CA subjects vs. 62 ± 7 ml·min·100 mmHg in AA subjects, P = 0.862). There was an intensity-dependent increase in FVC during exercise in both groups; however, AA subjects presented lower FVC (interaction P < 0.001) at 8-, 12-, 16-, 20-, and 24-kg workloads (e.g., 24 kg: 324 ± 20 ml·min·100 mmHg in CA subjects vs. 241 ± 21 ml·min·100 mmHg in AA subjects, P < 0.001). FBF responses to exercise were also lower in AA subjects (interaction P < 0.001), whereas MAP responses did not differ between groups (e.g., ∆MAP at 24 kg: +19 ± 2 mmHg in CA subjects vs. +19 ± 2 mmHg in AA subjects, interaction P = 0.950). These findings indicate lower hyperemic responses to rhythmic handgrip exercise in AA men compared with CA men. NEW & NOTEWORTHY It is known that African-American individuals have heightened vasoconstriction and reduced vasodilation under resting conditions compared with Caucasian-American individuals. Here, we identified that the hyperemic response to moderate and high-intensity rhythmic handgrip exercise was lower in healthy young African-American men.
先前的研究表明，与高加索裔美国人（CA）相比，非裔美国人（AA）在静息状态下具有更强的血管收缩和更低的血管舒张反应。然而，运动时血管反应的潜在差异尚不清楚。因此，我们假设与 CA 受试者相比，AA 受试者在进行节律性握力运动时，前臂血管传导率（FVC）的增加幅度会减弱。在健康的年轻 CA（n=10）和 AA（n=10）男性中，使用双功能多普勒超声测量前臂血流（FBF）和平均动脉压（MAP），并在进行 4、8、12、16、20 和 24 kg 的节律性握力试验时记录。在休息时，两组之间的 FVC（计算为 FBF/MAP）、FBF 和 MAP 相似（CA 受试者的 FVC 为 63±7 ml·min·100 mmHg，AA 受试者的 FVC 为 62±7 ml·min·100 mmHg，P=0.862）。两组在运动过程中均表现出 FVC 的强度依赖性增加；然而，AA 受试者在 8、12、16、20 和 24 kg 负荷时的 FVC 较低（交互作用 P < 0.001）（例如，24 kg：CA 受试者的 FVC 为 324±20 ml·min·100 mmHg，AA 受试者的 FVC 为 241±21 ml·min·100 mmHg，P < 0.001）。AA 受试者的 FBF 对运动的反应也较低（交互作用 P < 0.001），而两组之间的 MAP 反应没有差异（例如，24 kg 时的 ∆MAP：CA 受试者为 +19±2 mmHg，AA 受试者为 +19±2 mmHg，交互作用 P=0.950）。这些发现表明，与 CA 男性相比，AA 男性在进行节律性握力运动时，其充血反应较低。
新内容和值得注意的内容：与高加索裔美国人（CA）相比，非裔美国人（AA）在静息状态下具有更高的血管收缩和更低的血管舒张反应。在这里，我们发现健康的年轻非裔美国男性对中高强度节律性握力运动的充血反应较低。
