Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA.
School of Kinesiology, Neurovascular Physiology Laboratory, Auburn University, Auburn, AL, USA.
Physiol Rep. 2020 Sep;8(18):e14581. doi: 10.14814/phy2.14581.
Older adults have reduced fluid intake and impaired body fluid and electrolyte regulation. Older female adults exhibit exaggerated exercise blood pressure (BP) responses, which is associated with an increased risk of adverse cardiovascular events. However, it is unclear if dysregulated body fluid homeostasis contributes to altered exercise BP responses in older female adults. We tested the hypothesis that short-term water deprivation (WD) increases exercise BP responses in older female adults. Fifteen female adults (eight young [25 ± 6 years] and seven older [65 ± 6 years]) completed two experimental conditions in random crossover fashion; a euhydration control condition and a stepwise reduction in water intake over three days concluding with a 16-hr WD period. During both trials, beat-to-beat BP (photoplethysmography) and heart rate (electrocardiogram) were continuously assessed during rest, handgrip exercise (30% MVC), and post-exercise ischemia (metaboreflex isolation). At screening, older compared to young female adults had greater systolic and diastolic BP (p ≤ .02). Accelerometer-assessed habitual physical activity was not different between groups (p = .65). Following WD, 24-hr urine flow rate decreased, whereas thirst, urine specific gravity, and plasma osmolality increased (condition: p < .05 for all), but these WD-induced changes were not different between age groups (interaction: p ≥ .31 for all). Resting systolic and diastolic BP values were higher in older compared to young adults (p < .01 for both), but were not different between experimental conditions (p ≥ .20). In contrast to our hypothesis, WD was associated with attenuated systolic BP responses during handgrip exercise (post hoc: p < .01) and post-exercise ischemia (post hoc: p = .03) in older, but not young, female adults. These data suggest that reduced water intake-induced challenges to body fluid homeostasis do not contribute to exaggerated exercise BP responses in post-menopausal female adults.
老年人液体摄入减少，体液和电解质调节受损。老年女性表现出运动血压（BP）反应过度，这与不良心血管事件的风险增加有关。然而，尚不清楚体液稳态失调是否导致老年女性运动 BP 反应改变。我们检验了这样一个假设，即短期水剥夺（WD）会增加老年女性的运动 BP 反应。15 名女性成年人（8 名年轻[25±6 岁]和 7 名年长[65±6 岁]）以随机交叉方式完成了两种实验条件；在正常水合对照条件下和逐步减少三天的水摄入量，最后进行 16 小时的 WD 期。在两次试验中，通过光体积描记法（光电体积描记法）和心电图（心电图）连续评估静息、握力运动（30%最大握力）和运动后缺血期间的血压（代谢反射隔离）。在筛选时，与年轻女性相比，年长女性的收缩压和舒张压更高（p≤.02）。两组之间的习惯性体力活动的加速度计评估没有差异（p=.65）。WD 后，24 小时尿量减少，而口渴、尿比重和血浆渗透压增加（条件：所有 p<.05），但 WD 引起的这些变化在年龄组之间没有差异（交互作用：所有 p≥.31）。与年轻成年人相比，年长成年人的静息收缩压和舒张压更高（两者均为 p<.01），但在实验条件之间没有差异（两者均为 p≥.20）。与我们的假设相反，WD 与年长女性握力运动期间收缩压反应减弱（事后检验：p<.01）和运动后缺血期（事后检验：p=.03）相关，但在年轻女性中没有。这些数据表明，绝经后女性的体液稳态失调引起的水摄入减少挑战不会导致运动 BP 反应过度。
