
Yoga Nidra, which literally means "sleep of the yogis", is used to prepare both mentally and physically prior to seeking deeper levels of consciousness and awareness through meditation. However Yoga Nidra is also regularly practiced on its own as a daily relaxation technique. Adherents claim that half an hour of Yoga Nidra can replace up to three hours of normal sleep, although its regular use as a sleep substitute is not recommended as the body and mind still requires sufficient rest through standard sleep.
The true sleep of a Yogi is a state of consciousness in which the Yogi is believed to be connected with the Divine energy pervading the whole Cosmos. This energy is thought to be beyond space and time, allowing the Yogi to possibly see the past, the present and the future. A Yogi may also become aware of his past lives. Through Yoga Nidra the Yogi can work through Karmas, as this clarity penetrates levels of the subconscious. It is used to help purify the subconscious through use of certain vows known as Shankalpas. Experienced Yogis claim to use Yoga Nidra for astral travels and in its highest level it leads to Samadhi.
Yoga Nidra should not be confused with techniques of autosuggestion, or "autogenous training".
Paramyogeshwar Sri Devpuriji developed Yoga Nidra and passed it on to Sri Deep Narayan Mahaprabhuji and it was taught to his disciples since 1880. On his journeys to the Himalayas, Sri Devpuriji met, among others, Swami Sivananda of Rishikesh and Swami Muktananda, who is well known in Europe and conveyed the technique of Yoga Nidra to several Yogis and Swamis, such as Swami Satyananda Saraswati and Swami Janakananda.
The modern form of Yoga Nidra was constructed by Swami Satyananda about 40 years ago. The development of yoga nidra incorporated features from the ancient tantricpractice called nyasa. Nyasa was a practice whereby the practitioner mentally placed Sanskrit mantraswithin the body parts, while meditating on each part (of the body).
With Swami Satyananda's extensive worldwide touring and teaching, Yoga Nidra gradually spread throughout India, Europe, Australia and the United States and is taught in the system in Satyananda Yoga and Yoga in Daily Life.
The modern form of the Yoga Nidra practice exists today with 8 clearly defined stages (Internalisation, Sankalpa, Rotation of Consciousness, Breath Awareness, Manifestation of Opposites, Creative Visualization, Sankalpa, Externalisation) ; some stages
of the Yoga Nidra practice deepen pratyahara. Pratyahara is an effect as well as a state which is induced by the withdrawal of awareness from sensory perception. Yoga Nidra is best done as a guided practice, that is, with an experienced yoga teacher
who verbally delivers the instructions