Yoga Nidra—often called yogic sleep—is more than deep relaxation. In this episode of YogaInsightPod, we explore the scientific and historical foundations of Yoga Nidra, tracing its roots from ancient yogic texts to modern clinical research. Drawing on a comprehensive narrative review published in Sleep and Vigilance, this episode examines how guided yogic sleep influences the nervous system, brain function, stress physiology, sleep quality, and mental health. We discuss neuroimaging findings, autonomic regulation, hormonal balance, and clinical outcomes in conditions such as stress, anxiety, depression, insomnia, hypertension, and chronic pain—bridging ancient wisdom with modern science.