Quantifying the Influence of Yogic Breathwork on Cerebrospinal Fluid Circulation

修改项目摘要/摘要部分 瑜伽呼吸法是一种低风险、低成本的身心疗法，可以很容易地学习和执行，无需任何额外的设备。瑜伽呼吸练习已被证明对广泛的健康状况有效，包括睡眠和神经系统疾病。虽然潜在的机制仍然不完全清楚，但瑜伽呼吸的健康益处的一个先前研究的机制是通过副交感神经激活，如呼吸率降低，心率和血压降低以及心率变异性增加所证明的。另一个解释瑜伽呼吸法对健康有益的机制是它对脑脊液（CSF）循环的直接影响，由于缺乏非侵入性方法，迄今为止尚未进行研究。CSF通过大量流动（大循环）在中枢神经系统（CNS）周围循环，同时确保CNS的健康。由于动脉搏动和呼吸，CSF经历周期性搏动。虽然心脏驱动的CSF已被广泛研究，但由于缺乏实时非侵入性方法，因此对心脏驱动的CSF的了解并不充分。为了解决这一差距，我们最近开发了一种实时相位对比磁共振成像（RT-PCMRI）技术，并证明了深缓慢腹式呼吸-与自然呼吸相比-增加了CSF流速的幅度，同时降低了呼吸驱动的CSF流的频率，这表明呼吸模式对CSF循环的调制具有准即时影响。此外，CSF循环在维持胶质淋巴功能（微循环）中起着核心作用，这是最近发现的一种全脑清洁机制，支持CSF和间质液（ISF）的快速交换，并促进溶质和代谢废物从脑组织中清除，与清醒相比，优先在睡眠期间。为了评估人脑胶质淋巴功能，我们最近开发了一种新的非侵入性成像方法，结合睡眠-觉醒周期的同步多导睡眠图和磁共振波谱测量，这表明睡眠期间，特别是在慢波睡眠中胶质淋巴活动增强。因为我们知道CSF沿着血管周围通道进入促进啮齿动物的胶质淋巴功能，我们假设瑜伽呼吸对CSF流动动力学的影响也将促进胶质淋巴活动。因为我们知道瑜伽可以改善睡眠，与清醒相比，glymphatic功能主要在睡眠期间活跃，我们希望定期练习瑜伽呼吸法可以改善睡眠质量，并有利于glymphatic活动。因此，我们建议：（1）确定8周瑜伽呼吸练习干预对CSF流动动力学的影响;（2）确定8周瑜伽呼吸练习干预对CSF循环的影响（流动动力学和胶质淋巴功能），以及;（3）测量呼吸工作干预对参与者长期睡眠模式的影响，并将睡眠改善程度与目标2中测量的CSF循环变化相关联。

Modified Project Summary/Abstract Section Yogic breathwork is a low-risk low-cost mind-body therapy that can be easily learned and performed without any additional equipment. The practices of yogic breathwork have been demonstrated to be effective for a wide range of health conditions including sleep and neurological conditions. While underlying mechanisms are still not fully known, one previously studied mechanism for the health benefits of yogic breathwork is through parasympathetic activation as evidenced by decreased respiration rate, heart rate and blood pressure, and increased heart rate variability. Another mechanism for explaining the health benefits of yogic breathwork can be its direct influence on cerebrospinal fluid (CSF) circulation, which to date has not been investigated due to lack of non-invasive methodology. CSF circulates by bulk flow (macrocirculation) around the central nervous system (CNS) while ensuring the health of the CNS. CSF undergoes periodic pulsations due to arterial pulsation and respiration. While cardiac-driven CSF has been studied extensively, respiratory-driven CSF is not very well-understood due to lack of real-time non-invasive approaches. To address this gap, we have recently developed a real-time phase-contrast magnetic resonance imaging (RT-PCMRI) technique, and demonstrated that deep slow abdominal breathing - compared to natural breathing - increases the amplitude of the CSF flow velocities while lowering the frequency of respiratory-driven CSF flow, suggesting that breathing patterns have quasi-immediate influence on the modulation of CSF circulation. Additionally, CSF circulation plays a central role in maintaining glymphatic function (microcirculation), which is a recently identified brain-wide cleaning mechanism that supports the rapid interchange of CSF and interstitial fluid (ISF), and facilitates the clearance of solutes and metabolic wastes from the brain interstitium, preferentially during sleep compared to wakefulness. In order to evaluate glymphatic function in human brain, we have recently developed a novel non-invasive imaging approach incorporating simultaneous polysomnography and magnetic resonance spectroscopy measurements across sleep-wakes cycles, which indicated enhanced glymphatic activity during sleep, particularly in slow wave sleep. Because we know that the entry of CSF along perivascular channels facilitates glymphatic function in rodents, we hypothesize that the influence of yogic breathwork on CSF flow dynamics will also facilitate the glymphatic activity. Because we know yoga improves sleep, and glymphatic function is mainly active during sleep compared to the wakefulness, we expect that a regular practice of yogic breathwork will improve sleep quality, and will benefit the glymphatic activity. Thus, we propose to: (1) determine the influence of an 8-week yogic breathwork intervention on CSF flow dynamics; (2) determine the influence of an 8-week yogic breathwork intervention on CSF circulation (flow dynamics and glymphatic function), and; (3) measure the effects of the breathwork intervention on participants’ long-term sleep patterns, and correlate the degree of sleep improvement with the changes in CSF circulation measured in Aim 2.