Nidra translates to sleep, so yoga nidra is yogic sleep. You've probably heard about this magical practice that allows you to lay down for 20-45 minutes and experience profound health benefits, but how is it any different from the relaxation at the end of a yoga class? Yoga Nidra is a fully guided meditation practice done lying down. There is no need to concentrate or control your breath, you simply follow instructions that circle your consciousness around your entire physical body while trying not to fall asleep. Instructions guide practitioners into the “hypnagogic state”, or the threshold between alpha and theta brain waves, where the body “sleeps” while the mind is lucid. Swami Satyananda Saraswati, who pioneered the practice in the early 1950s, calls it “reaching the border between waking and sleeping states.” This passive/active state allows access to subconscious memory. A cognitive behavioural therapist would describe this as "brain placidity" or the ability to disengage old neural pathways and reinforce new, healthy ones. Yoga nidra is essentially making space for the brain to rewire negative thought patterns and destructive habits. (HuffPost - How Yoga Nidra Works)
The 7 Stages of Yoga Nidra - as adapted from Yoga Nidra by Swami Satyananda Saraswati
1. Guided Relaxation - through stillness and breathing you balance the sympathetic and parasympathetic nervous systems as well as the left and right sides of your brain. Your brain shifts from beta, an awakened state with lots of brain activity, to alpha, a more relaxed state. In alpha, the mood-regulating hormone serotonin gets released and this calms you down. (Yoga Journal - Your Brain on Yoga Nidra)
2. Resolve - you choose a short, positive and clear statement in the present tense that will hopefully penetrate to your subconscious mind. Choose only one, without rushing, and repeat several times at the beginning and end of the practice. Time and sincerity is needed to plant this resolve in the mind. The result depends on the deep felt need to gain the goal of the resolve.
3. Rotation of Consciousness - a practice of remaining aware, listening to the voice guiding you, mentally repeating the name of the body part as it is mentioned, visualizing the body part and then moving on to the next.
4. Awareness of Breath - an awareness of the breath with no attempt to force or change it. This helps with sense withdrawal. Energy liberated from sense withdrawal is directed towards healing and rejuvenation of over taxed tissues, glands and organs.
5. Awareness of Feelings and Sensations - this is a relaxation on the plane of feelings and emotions. Feelings that are physical or emotional are awakened, experienced and then removed. Usually this is practiced with pairs of opposite feelings, such as heat and cold, heaviness and lightness, pain and pleasure. The pairing of feelings harmonizes the opposite hemispheres of the brain and helps in balancing our basic drives and controlling functions that are normally unconscious.
6. Visualization - the use of images described by the instructor to bring the hidden contents of the subconscious mind into the conscious mind. This works because the subconscious stores information in the form of symbols and images. Images can include landscapes, oceans, mountains, temples and symbols such as an egg or flower. This practice develops self awareness and relaxes the mind by purging it of painful associations. This practice also leads the mind to deep concentration or meditation. This stage usually ends with a visualization that evokes profound feelings of peace and calmness.
7. Resolve - at this point the mind is at peace and the subconscious mind is very receptive to positive thoughts and suggestions. The practice ends with a resolve. The direct order from the subconscious mind to the conscious mind is the seed enabling one to radically change one's attitude, behaviour and path. Said with sincere faith the resolve will have a stronger effect on the subconscious mind and will be more likely to become a reality in one's life. The practitioner is then slowly guided back from yogic sleep to the waking state. The practice is complete.
The deep relaxation experienced in yoga nidra is said to bring about the following benefits: relieved insomnia, lower blood pressure, improved digestion, reduced mental fatigue, balanced emotions, strengthened immune system and regulated hormone secretions.
In two separate papers published in the Indian Journal of Physiology and Pharmacology researchers found yoga nidra improved blood pressure, heart rate variables, and hormone irregularities in women. All of this comes in connection with numerous studies firmly establishing measurable therapeutic effects of meditation, no matter the method, on everything from metabolic syndrome to clinical depression (NY Times - Contemplation Therapy).
Hopefully this article, and the linked articles, are helpful in your understanding of this profound wellness practice. If you have any further questions, feel free to reach out!