Quantifying the Influence of Yogic Breathwork on Cerebrospinal Fluid Circulation

修改后的项目摘要/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进行，而不需要任何额外的设备。瑜伽呼吸练习已被证明对包括睡眠和神经疾病在内的各种健康状况都有效。虽然潜在的机制仍不完全清楚，但先前研究的瑜伽呼吸对健康有益的机制之一是通过副交感神经激活，呼吸频率、心率和血压的降低以及心率变异性的增加就是证据。解释瑜伽呼吸对健康益处的另一种机制是它对脑脊液循环的直接影响，由于缺乏非侵入性方法，迄今尚未对其进行研究。脑脊液在确保中枢神经系统(CNS)健康的同时，通过大量流动(大循环)在中枢神经系统(CNS)周围循环。由于动脉搏动和呼吸，脑脊液经历周期性的脉动。虽然心脏驱动的脑脊液已经得到了广泛的研究，但由于缺乏实时无创的方法，呼吸驱动的脑脊液还没有得到很好的理解。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，并证明了与自然呼吸相比，深而缓慢的腹式呼吸增加了脑脊液流速的幅度，同时降低了呼吸驱动的脑脊液流动的频率，这表明呼吸模式对脑脊液循环的调节具有准即时的影响。此外，脑脊液循环在维持淋巴功能(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，支持脑脊液和间质液体(ISF)的快速交换，并促进溶质和代谢废物从脑间质中清除，与清醒相比，睡眠时更好。为了评估人脑的淋巴功能，我们最近开发了一种新的非侵入性成像方法，结合多导睡眠图和磁共振波谱在睡眠-唤醒周期中的测量，表明在睡眠期间，尤其是在慢波睡眠中，淋巴活动增强。由于我们知道脑脊液沿血管周围通道进入可促进啮齿类动物的淋巴功能，因此我们推测瑜伽呼吸对脑脊液流动动力学的影响也将促进淋巴活动。因为我们知道瑜伽可以改善睡眠，而且与清醒时相比，睡眠期的咽喉功能主要是活跃的，我们预计定期练习瑜伽呼吸法将改善睡眠质量，并有利于咽喉活动。因此，我们建议：(1)确定为期8周的瑜伽呼吸干预对脑脊液血流动力学的影响；(2)确定为期8周的瑜伽呼吸干预对脑脊液循环(血流动力学和淋巴功能)的影响；(3)测量呼吸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中测量的脑脊液循环的变化相关联。

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.