正念冥想是“冥想的一種類型，專注于體會當前的感受，對這些感受不作任何類型的認知加工，不作判斷，不試圖改變這些感受”. 由于在正念冥想過程中觀察到了呼吸頻率下降，因此一個患者亞組完成了第3次訪視，他們在訪視中采用控制性呼吸以作為第2種對照措施。在這次訪視中，他們把呼吸頻率降低至與正念冥想時相同的頻率。
亞特蘭大——在美國腎病學會主辦的“2013腎臟周”上，來自埃默里大學的Jeanie Park博士報告稱，一項小規模隨機試驗表明正念冥想可能有助于改善慢性腎病（CKD）合并高血壓患者的血壓控制情況。
這項試驗納入了15例3期慢性腎病合并高血壓的患者。受試者均為男性退伍軍人，以隨機交叉的形式完成了2次試驗訪視，一次在指導下進行14分鐘的正念冥想，另一次則接受14分鐘的血壓教育作為對照。
結果顯示，與涉及血壓教育的對照措施相比，正念冥想與更大幅度的收縮壓下降（–10.2 vs. –0.8 mmHg）、舒張壓下降（–6.4
vs. –1.8 mmHg）和平均動脈血壓下降（–7.7 vs. –1.4
mmHg）相關，差異有統計學意義。此外，微神經圖顯示，正念冥想還與更大幅度的肌肉交感神經活性下降（–10.7 vs.
1.9次脈沖/分）相關，差異也有統計學意義。
Park博士說：“我們觀察到在正念冥想過程中，交感神經活性較之對照組顯著下降，但在控制性呼吸過程中……交感神經活性并無明顯差異。這說明緩慢呼吸本身不足以降低血壓和交感神經活性，正念冥想可能起到了某種特別的調節交感神經活性和血壓的作用。”
雖然過去也有研究表明正念冥想在高血壓患者中可以起到“適度但有意義”的效應，但我們這項研究的結果第一次在慢性腎病合并高血壓患者中證明了正念冥想與血壓下降之間的相關性。這種效應可能是由交感神經系統活性急性下降介導的。
Park博士解釋道，慢性腎病以慢**感神經系統活性過高為特征，這會在一定程度上導致高血壓和死亡。她說：“在臨床實踐中，我們希望阻斷交感神經活性以降
低血壓。我們采用β受體阻滯劑、[**]等抗高血壓藥物來達到這一目的，但問題是這些藥物往往因其副作用而使用受限……所以，顯然我們有必要為患者尋
找其他替代或附加療法以對抗交感神經活性并降低血壓。”
Park博士總結道，這項研究的結果表明正念冥想可能對自主神經控制的確有生理效應，它可能有望成為慢性腎病患者的一種補充療法。她也指出，未來研究需要明確正念冥想是否能發揮長時間的降壓效應。
正念冥想可調節個體的負性情緒、促進個體正性情緒，對于心身疾病具有顯著的干預效用。正念冥想的再感知模型、正念應對模型、推動性上升螺旋模型以及正念情
緒調節模型都強調了正念冥想對情緒的調節作用。認知神經科學的研究發現，正念冥想可促進左側前額葉腦區激活增強，涉及的腦區主要包括背外側前額葉皮層
（DLPFC）和背內側前額葉皮層（DMPFC）。研究者進一步發現，正念特質是通過改善前額葉對邊緣系統反應的調節來實現對情緒的調節作用。而且，這種調節作用還有可能體現為通過冥想訓練分離聯結在一起
的兩種自我參照神經機制，從而加強體驗性神經機制。另外，研究者還發現，正念冥想訓練還可以改變與情緒加工相關的大腦結構。進一步澄清冥想訓練與大腦偏側
化的關系和不同類型被試之間的比較研究將成為該領域日后研究的重點。
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.