WHY YOGA NIDRA?

From Lectures on Yoga

Swami Satyanand Saraswati

Important fact we need to know is: Sleep is a state of consciousness involving physiological states. Sleep is not a physiological state; it is a mental state. At the same time, the biological situation influences the psychological state. A certain amount of disharmony is created in the secretions, and those secretions, when they pass through the blood vessels, can cause inertia in the coronary system, which can also cause what we call bad sleep or insomnia.

THE AUTONOMOUS METHOD

When you train a person in the practice of yoga nidra, they develop a quality of controlling sleep through mental processes.

A simple illustration: when you do not get sleep, you usually take a few sedatives which work through the blood vessels or nervous system to create a natural state of sleep by influencing biological processes.

Another possibility is to find an autonomous method—such as yoga nidra—to create an automatic, voluntary state of sleep by training the mind and thereby training the biological functions.

External vs. Voluntary Sleep

In both the sedative and psychological methods, sleep is brought from the outside and is involuntary. However, yoga nidra has one key difference:

• Sedatives: You depend on the existence of external chemicals, whose far-reaching reactions are uncertain.
• Yoga Nidra: This is a very harmless method. It is known as yoga nidra (sleep after throwing off the burdens) rather than just nidra (sleep, no matter how or why).

THE BRAIN WAVE DIFFERENCE

Ordinarily, when sleep comes, a person's brain waves slowly descend through the sequence: beta (awake/thinking) → theta → delta (deep sleep).

In yoga nidra, the process is different: normal waves → alpha waves → delta waves.

Most people sleep without resolving their tensions because they jump from beta to theta and delta all at once without cultivating alpha waves. Relaxation takes place when alpha waves become intense. Because yoga nidra intentionally moves through the alpha wave stage (relaxation), the quality of sleep created is higher in its reflections on the body.

BRAIN WAVE BREAKDOWN

• Beta waves (13–30 cycles per second): Suggest alert functioning of the waking state and are associated with normal daily activities.
• Alpha waves (8–13 cycles per second): Indicate deep physical relaxation and mental calmness.
• Theta waves (4–8 cycles per second): Associated with concentration and meditation, dreams, hypnosis, and hypnogogic imagery.
• Delta waves (0.4–3 cycles per second): Most consistent with deep non-REM (dreamless) sleep.