冥想可能有助于慢性肾病患者降低血压

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。



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”。

这项试验纳入了15例3期CKD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。

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。

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CKD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，CKD以慢性交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、[氯硝西泮]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CKD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。

Park博士声明无相关利益冲突。

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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.