BLOOD PRESSURE EFFECTS OF BEHAVIORAL STRESS / SODIUM LOADING

行为压力/钠负荷对血压的影响

• 批准号: 6245395
• 负责人: JENNIFER A HAYTHORNTHWAITE
• 金额: $ 2.23万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-03-05 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6245395
• 关键词: behavioral /social science research tag; blood pressure; cardiovascular disorder prevention; clinical research; cortisol; dietary sodium; human subject; hypertension; neuroendocrine system; norepinephrine; nutrition related tag; psychological stressor; urinalysis

This study examines the physiological and psychological factors associated with blood pressure elevations in normotensive adults. The long-term goal of this research is the development and refinement of preventative interventions for hypertension, either behavioral or dietary, that can be directed at those individuals who are most vulnerable to the synergistic blood pressure effects of behavioral stress and a high sodium intake. Medical students at Johns Hopkins University School of Medicine participated in two different parts of the study, once during the two-week examination period and once during a stressful laboratory protocol. Forty-two medical students wore ambulatory blood pressure monitors during a lecture and during the examination while maintaining the high sodium (N=28) and regular sodium intake (N=14). The stress of taking an examination was associated with a lowering of plasma potassium, an increase in plasma cortisol, and a tendency to increase plasma sodium. As expected, blood pressure and heart rate were elevated during the examination relative to the lecture period, but the magnitude of these elevations were not influenced by sodium intake. Timed urine samples were collected and the examination was associated with a reduction in urinary excretion rate, although both urinary cortisol and urinary norepinephrine tended to increase during the stressful examination. Urinary cortisol excretion during the examination was greater among the high sodium group, whereas urinary norepinephrine excretion tended to be lower in the high sodium group. Urinary sodium excretion data were used to identify subsets of individuals, including sodium retainers (48% decreased urinary sodium excretion rate (Una) during the exam relative to the lecture) and sodium excreters (52% increased Una). Sodium retainers showed higher sodium excretion rates during the control (lecture) conditions and lower sodium excretion rates during exposure to the stressor. These individuals also showed lower overnight sodium excretion before the stressful examination. Sodium retainers showed a tendency for greater blood pressure reactivity to the stressful examination, a tendency for higher levels of urinary norepinephrine excretion during the examination, and a tendency for higher resting levels of aldosterone collected 30 minutes before the exam. In a second study, medical students (N=7) completed a 4.5 hr laboratory protocol designed to examine acute cardiovascular, neurohormonal, and renal responses to a stressful interview. Stress- induced sodium retention was observed in 29% of the sample. Preliminary results indicate that stress-induced sodium retention was associated with higher levels of plasma adrenocroticotrophin hormone and aidosterone levels, although both groups showed comparable blood pressure elevations in response to the stressful interview. Stressinduced sodium retention was observed to continue into the one- hour recovery period. These findings suggest the importance of adrenocortical activation, particularly aldosterone stimulation, in response to behavioral challenges as a possible mediator of stress- related sodium retention.

本研究探讨了生理和心理因素 与血压正常成人的血压升高有关。 的 这项研究的长期目标是开发和完善 高血压的预防性干预，无论是行为还是 饮食，可以针对那些最 易受行为性高血压的协同效应影响， 压力和高钠摄入 约翰霍普金斯大学的医学生 大学医学院参加了两个不同的部分， 研究，一次在两周的检查期间，一次在一个 紧张的实验室协议。 42名医学生穿着 动态血压监测仪在讲座期间， 在维持高钠（N=28）和常规钠的同时进行检查 摄入（N=14）。 参加考试的压力与 血浆钾降低，血浆皮质醇升高， 增加血浆钠的趋势。 如预期，血压和 相对于讲课，考试期间心率升高 但这些上升的幅度并没有受到 钠摄入量 收集定时尿样， 与尿排泄率的降低有关，尽管两者 尿皮质醇和尿去甲肾上腺素倾向于增加 紧张的考试。 尿皮质醇排泄 高钠组的检查结果更高，而尿 高钠组的去甲肾上腺素排泄往往较低。 尿钠排泄数据用于确定 个体，包括钠固位剂（尿钠减少48% 排泄率（Una）在考试期间相对于讲座）和钠 排泄物（Una增加52%）。 钠潴留显示钠含量较高 在控制（演讲）条件下的排泄率和低钠 排泄率在暴露于应激源。 这些人也 显示出较低的夜间钠排泄前的压力 考试 钠潴留显示出更大的血 压力反应，压力考试，倾向于更高 检查期间尿去甲肾上腺素排泄水平，以及 30分钟内收集的醛固酮静息水平较高的趋势 在第二项研究中，医学生（N=7）完成了 设计用于检查急性心血管的4.5小时实验室方案， 神经激素和肾脏对紧张面试的反应 压力- 在29%的样品中观察到诱导的钠保留。 初步 结果表明，应激诱导的钠潴留与 血浆促肾上腺皮质激素水平较高， 醛固酮水平，虽然两组显示出可比的血液 在紧张的面试中压力会升高。 观察到应力诱导的钠潴留持续到一个- 小时恢复期。 这些发现表明， 肾上腺皮质激活，特别是醛固酮刺激， 对行为挑战的反应可能是压力的媒介 与钠潴留有关。