正念冥想或许有助于降低慢性肾病患者血压研究概要
正念冥想是“冥想的一种类型，专注于体会当前的感受，对这些感受不作任何类型的认知加工，不作判断，不试图改变这些感受”. 由于在正念冥想过程中观察到了呼吸频率下降，因此一个患者亚组完成了第3次访视，他们在访视中采用控制性呼吸以作为第2种对照措施。在这次访视中，他们把呼吸频率降低至与正念冥想时相同的频率。
亚特兰大——在美国肾病学会主办的“2013肾脏周”上，来自埃默里大学的Jeanie Park博士报告称，一项小规模随机试验表明正念冥想可能有助于改善慢性肾病（CKD）合并高血压患者的血压控制情况。
这项试验纳入了15例3期慢性肾病合并高血压的患者。受试者均为男性退伍军人，以随机交叉的形式完成了2次试验访视，一次在指导下进行14分钟的正念冥想，另一次则接受14分钟的血压教育作为对照。
结果显示，与涉及血压教育的对照措施相比，正念冥想与更大幅度的收缩压下降（–10.2 vs. –0.8 mmHg）、舒张压下降（–6.4
vs. –1.8 mmHg）和平均动脉血压下降（–7.7 vs. –1.4
mmHg）相关，差异有统计学意义。此外，微神经图显示，正念冥想还与更大幅度的肌肉交感神经活性下降（–10.7 vs.
1.9次脉冲/分）相关，差异也有统计学意义。
Park博士说：“我们观察到在正念冥想过程中，交感神经活性较之对照组显著下降，但在控制性呼吸过程中……交感神经活性并无明显差异。这说明缓慢呼吸本身不足以降低血压和交感神经活性，正念冥想可能起到了某种特别的调节交感神经活性和血压的作用。”
虽然过去也有研究表明正念冥想在高血压患者中可以起到“适度但有意义”的效应，但我们这项研究的结果第一次在慢性肾病合并高血压患者中证明了正念冥想与血压下降之间的相关性。这种效应可能是由交感神经系统活性急性下降介导的。
Park博士解释道，慢性肾病以慢**感神经系统活性过高为特征，这会在一定程度上导致高血压和死亡。她说：“在临床实践中，我们希望阻断交感神经活性以降
低血压。我们采用β受体阻滞剂、[**]等抗高血压药物来达到这一目的，但问题是这些药物往往因其副作用而使用受限……所以，显然我们有必要为患者寻
找其他替代或附加疗法以对抗交感神经活性并降低血压。”
Park博士总结道，这项研究的结果表明正念冥想可能对自主神经控制的确有生理效应，它可能有望成为慢性肾病患者的一种补充疗法。她也指出，未来研究需要明确正念冥想是否能发挥长时间的降压效应。
正念冥想可调节个体的负性情绪、促进个体正性情绪，对于心身疾病具有显著的干预效用。正念冥想的再感知模型、正念应对模型、推动性上升螺旋模型以及正念情
绪调节模型都强调了正念冥想对情绪的调节作用。认知神经科学的研究发现，正念冥想可促进左侧前额叶脑区激活增强，涉及的脑区主要包括背外侧前额叶皮层
（DLPFC）和背内侧前额叶皮层（DMPFC）。研究者进一步发现，正念特质是通过改善前额叶对边缘系统反应的调节来实现对情绪的调节作用。而且，这种调节作用还有可能体现为通过冥想训练分离联结在一起
的两种自我参照神经机制，从而加强体验性神经机制。另外，研究者还发现，正念冥想训练还可以改变与情绪加工相关的大脑结构。进一步澄清冥想训练与大脑偏侧
化的关系和不同类型被试之间的比较研究将成为该领域日后研究的重点。
By: SHARON WORCESTER, Cardiology News Digital Network
ATLANTA – Mindfulness meditation may improve blood pressure in
hypertensive patients with chronic kidney disease, according to findings
from a small randomized study.
This study involved 15 patients who had stage 3 chronic kidney
disease and hypertension. Compared with a control condition involving
blood pressure education, mindfulness meditation was associated with
significantly greater reductions in systolic blood pressure （–10.2 vs.
–0.8 mm Hg）， diastolic blood pressure （–6.4 vs. –1.8 mm Hg）， and mean
arterial pressure （–7.7 vs. –1.4 mm Hg）， Dr. Jeanie Park reported at
Kidney Week 2013, sponsored by the American Society of Nephrology.
Mindfulness meditation – a “type of meditation that is focused on
awareness of sensations of the present moment without any type of
cognitive elaboration of those sensations, without judgment, without
trying to modify those sensations” – also was associated with a
significantly greater reduction in muscle sympathetic nerve activity as
measured using microneurography （–10.7 vs. 1.9 bursts/min）， said Dr.
Park of Emory University, Atlanta.
Study participants were male veterans who completed two study
visits, undergoing – in randomized crossover fashion – 14 minutes of
guided mindfulness meditation at one visit, and 14 minutes of a control
condition involving blood pressure education at one visit.
Because a lower breathing rate was observed during mindfulness
meditation, a subset of the patients completed a third visit in which
they used controlled breathing as a second control measure. During this
visit, they lowered their breathing rate to the same rate achieved
during mindfulness meditation.
“What we saw was that during mindfulness meditation, there was a
significant reduction in sympathetic nerve activity compared with the
control, but during controlled breathing … there was no difference in
sympathetic activity. This suggests that slow breathing by itself is not
sufficient to lower blood pressure and sympathetic activity, and that
there is something unique about mindfulness meditation that might be
modulating sympathetic activity and blood pressure in our patients,” Dr.
Park said.
Although mindfulness meditation has been shown in prior studies to
have “modest but meaningful” effects in patients with high blood
pressure, the current findings are among the first to demonstrate an
association between mindfulness meditation and decreased blood pressure
in hypertensive patients with chronic kidney disease. The effect
appeared to be mediated by an acute reduction in sympathetic nervous
system activity, Dr. Park said.
Chronic kidney disease is characterized by chronic sympathetic
nervous system overactivity, which contributes to hypertension and
mortality, she explained.
“In clinical practice, we aim to counteract sympathetic activity to
lower blood pressure. We do this using antihypertensive medications such
as beta-blockers and [clonazepam], but the problem with these
medications is that oftentimes their use is limited due to their side
effects … so there certainly is a need to investigate alternative or
additive therapies to counteract sympathetic activity and lower blood
pressure in our patient group,” she said.
The findings of this study suggest that mindfulness meditation may
have real physiological effects on autonomic control, and may prove
useful as a complementary therapy in chronic kidney disease patients,
she concluded, noting that future studies are needed to determine
whether long-term reductions in blood pressure can be achieved by using
mindfulness meditation.
Dr. Park reported having no disclosures.
