What is Yoga Nidra?

ORIGINALLY PUBLISHED AT http://www.manlyyoga.com.au/blog/what-yoga-nidra

Yoga Nidra is a potent technique that teaches you to relax consciously. It is a systematic method of physical, mental and emotional relaxation. 
 
It is both a deep relaxation and a meditation practice done from a lying down position. It’s also one of the easiest relaxation and meditation techniques, making it suitable for all levels of experience.
 
Yoga Nidra has many health benefits such as alleviating stress, tension, anxiety and insomnia.
 
Yoga Nidra can be thought of as ‘yogic sleep’. Yoga means union and Nidra means sleep. In Yoga Nidra the aim is to unite your awareness with the act of sleeping. Externally it may look like you are sleeping, but internally the awareness is awake and you are conscious of the deeper layers of the mind.
 
In Yoga Nidra the awareness hovers on the borderline between waking and sleeping. This is known as the hypnogogic state. Being in this state gives you access to your subconscious mind. And there you come to know yourself and your mind.
 
When practising Yoga Nidra it is not necessary to concentrate or try very hard. All that is necessary is that you maintain awareness of the teacher’s voice and follow the instructions mentally.
 
A full Yoga Nidra practice has 8 stages and usually takes around 30 minutes to complete. The sequencing of the 8 stages is essential to its effectiveness.
The stages take the practitioner on a journey from gross external awareness to subtle internal perception and back out again.
 
Stages of Yoga Nidra
 
1. Initial preparation
This initial stage is for settling and getting ready for the practice both physically and mentally. Here you make sure that you’ll be warm and comfortable and that you won’t be disturbed for the duration of the practice.
 
2. Sankalpa or resolve
In Yoga Nidra we make use of a sankalpa which can be translated as a resolve. The sankalpa is repeated 3 times at the beginning and the end of the practice.
 
3. Rotation of awareness through the different body parts
In this stage you are instructed to move your awareness through the parts of the body. The rotation is always the same. With repetition you get to know the body rotation off by heart. Over time the body builds a memory which associates the body rotation with relaxation. The relaxation response becomes easier and easier to activate each time you practise Yoga Nidra.
The purpose of this stage is to simultaneously awaken prana or vitality in each body part while also letting go of tension in each part. There is a neuronal map of the physical body in the brain known as the motor homunculus or ‘the little man’. All the body parts which awareness passes through in Yoga Nidra are located in that brain map. 
By moving the awareness systematically through all the different body parts, the physical body is transcended and the awareness is drawn within.
 
4. Breath awareness
Here the awareness is directed towards the breath. This could be watching the breath at the nostrils, chest, or abdomen. Or it could be in the passage between the navel and the throat. Often one is instructed to be aware of each incoming and outgoing breath by counting them mentally. Awareness of the breath develops relaxation and concentration. The focus on the breath also shifts the awareness to a more subtle level. 
 
5. Opposite feelings and sensations
In this stage, pairs of opposite feelings or sensations, such as heat and cold, heaviness and lightness, pain and pleasure, are recalled and experienced fully. Over time the student’s ability to evoke these sensations improves. The ability to evoke these sensations so that they are truly felt, is a reflection of an awake and creative mind. 
Through evoking and letting go of these opposite sensations the practitioner also learns detachment. We can learn to observe the sensation of either hot or cold without adding a judgment that the sensation is either bad or good.  We learn that sensations are temporary and that it is possible not to react to sensations.
 
6. Visualisation
 In the stage of visualisation, the awareness is taken to the dark space in front of the closed eyes, known as chidakasha. The student is instructed to visualise either random, unconnected images, or connected scenes. 
For example, random images could be, a car moving on a road, a horse, a gum tree, a sunset, the ocean, field grass, a standing dog, the colour purple, a spider web, a red rose. This technique of random, unconnected images is to release mental tensions. 
Sometimes connected scenes or a story visualisation are used. Story visualisations are most commonly visualising yourself walking through a nature landscape and being aware of the different sights, sounds and smells.
Story visualisations require a little more concentratration and their purpose is more to develop the capacity to visualise. 
 
7. Sankalpa again is repeated 3 times
 
8. Externalisation
In the last stage, time is spent externalising the awareness from the subtle inner dimension back out to the external world. This done by moving awareness through the physical body, the breath, and the outside sounds.