Yoga Nidra is an experience, a yogic state - traditionally it belongs to the higher stages of raja yoga with different yogic practices that induce this state of meditation. The modern, widespread practice uses adapted techniques accessible to the modern and western mind. It is experienced lying down in savasana with guided verbal instructions that occupy the mind through rotation of consciousness and visualizations - and may include breath awareness, awareness of sensations and feelings and awareness of subtle body elements. It is an experience of expanded awareness in a state of deep relaxation, promoting parasympathetic dominance, calming the physical body, mind, brain, senses, and nervous system - that eventually leads us into a meditative state. As the body relaxes, remaining aware as a witness, we move into a subtle state of deep conscious sleep (the state between wakefulness and sleep). With pratyahara (sense withdrawal), we work through levels of the unconscious and subconscious, removing energetic blockages which can be in the form of trauma, stress, health issues, physical and emotional disturbances. This experience is a powerful way to set our intention and plant it’s seeds with our Sankalpa (Resolve, Resolution, Force of Will) which is established during yoga nidra. When our mind is calm and quiet during yoga nidra it is more receptive and sensitive to our intentions as they are impressed on the subconscious mind.
Yoga nidra's common application is used as a therapeutic tool to address a wide range of mental, emotional and physical distress while embedding positive affirmations (sankalpa). It is an important complimentary practice for relieving disturbances in our asana and meditation disciplines - as well as to help us make positive shifts in our lives. As practitioners are able to establish a non guided, regular personal practice, yoga nidra may bring us to higher states of consciousness.
My personal experience of yoga nidra has been through my yogic meditation practices as well as guided practices. The sessions I offer use the guided yoga nidra practices from Swami Satyananda & Dr. Marc Halperin.