Many teachers and committed practitioners report subtle but powerful somatic effects when practicing bandhas, kumbhaka, and slow deep breathing. Recent imaging work suggests these practices can also change measurable cerebrospinal fluid motion. This summary reviews the relevant physiology, the current evidence, and safety-first guidance for classroom use. Links to Ashtanga Tech resources support follow-up study. ncbi.nlm.nih.gov 1. Quick physiology primer CSF bathes the brain and spinal cord, cushions the central nervous system, distributes signaling molecules, and clears metabolic waste. Daily CSF production and turnover support these tasks. Reduced turnover has been associated with impaired clearance and increased risk for neurodegenerative processes. CSF movement is pulsatile and driven by cardiac and respiratory forces, vasomotion, posture, and neural activity. Breathing pattern and thoraco-abdominal mechanics can shift the…