If you’re a yoga student, you’ll come across the concept of Yoga Nidra.
It’s a very ancient tradition, and a lot of people think of it as a system of relaxation. But Yoga Nidra is more than physical relaxation.
When we talk about relaxation in the West we’re generally talking about a state of physical relaxation, whereas Yoga Nidra is actually a state of relaxation of both mind and body.
In fact it’s a state of mind somewhere between wakefulness and sleep. It’s been described in various ways, but the description I like most is “a state of conscious deep sleep.”
States of mind – dreaming, daydreaming, meditating, thinking – are defined, or at least identified, by the frequency of electrical activity in the brain.
During Yoga Nidra, you may look like you are asleep, but the brain waves you produce during this time suggest the unconscious mind is working at a deeper level. During sleep, as you’re well aware, we lose consciousness of ourselves, but in Yoga Nidra we do not – sure, consciousness of the world is reduced, and physical relaxation is deep (as it can be in sleep), but there is nonetheless an inward consciousness which is lucid and you will be able to recall your thoughts and mental experiences later on.
From one point of view Yoga Nidra is an effortless, aimless relaxation. It’s best practiced with an experienced yoga teacher who can guide you through it, verbally.
There are two reasons for this: it’s a lot easier to be facilitated than it is to facilitate yourself into a state of deep relaxation with conscious awareness.
The second is that each yoga teacher will have a particular take on the concept of Yoga Nidra. If you can stick to a teacher who has a clear view of what they are trying to do in Yoga Nidra, you’re not going to become confused by different approaches espoused by different yoga teachers.
From a scientific point of view, there is some evidence to suggest that the state of mind you entered during Yoga Nidra practice is a state of unified transcendental consciousness.
This was first identified at the Menninger Foundation in the United States in the early ’70s, under the direction of Elmer Green, who recorded the brainwaves on an EEG machine of an Indian yogi who went through the practice of Yoga Nidra – involving the successive relaxation of his physical, mental and emotional being.
Of course the subject of this experiment, Swami Rama, had plenty of experience in entering this special state of consciousness, but nonetheless the remarkable changes in his brainwaves testified that Yoga Nidra is indeed a different state of mind.
For example, soon after entering Yoga Nidra, 75% of Swami Rama’s brainwaves were in the Alpha frequency – a frequency which is known to be associated with lucid dreaming and deep relaxation.
With more prolonged periods in Yoga Nidra, the Swami’s brainwaves were 75% Theta waves; this was associated with deep relaxation.
According to the Swami, in Theta states he had an internal experience which was, to paraphrase, “busy”, with desires, memories and images and other mental thought forms arising in what he described as an archetypal form.
While I’m not quite sure what this means, I would assume it implies the experience of powerful mental images which represented some fundamental aspect of his emotional and physical being.
The Swami could also enter a state of mind where his brain produced mostly Delta waves – which are the normal brain rhythm of deep sleep.
Interestingly enough, however, the Swami remained perfectly aware and conscious during this period – which is most unusual.
This 1970s investigation was probably the first time that such control over levels of consciousness and been demonstrated under laboratory experimentation.
And interestingly enough, to remain consciously aware while the brain is in the Delta wave frequency band is one of the indications said to be representative of the third state (prajna) of the four states of consciousness described in the Mandukya Upanishad.
For most of us, however, the experience of Yoga Nidra will be a simple form of deep relaxation which takes us into the Alpha wave frequency band, with all the benefits that are known to accrue from that, particularly around a big reduction in emotional arousal and level of stress.