Each time you practice yoga nidra meditation, you’re stilling the waves of the mind through conscious entry into the sleep state. How?
You start with sensing the body and breathing in specific ways in order to trigger the relaxation response. The relaxation response balances the sympathetic and parasympathetic nervous systems, and balances the left and right brain. In the process, 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. People who spend little time in an alpha brain-wave state have more anxiety than those who spend more time in alpha. Think of a car: if you want to stop and turn off the engine, you first need to downshift. Shifting your brain into an alpha state starts its process of “powering down,” or coming into a rest state with slower, restorative brain-wave activity.
See also 10 Steps of Yoga Nidra
How Yoga Nidra Guided Meditation Works
From alpha, you go into a deep alpha and high theta brain-wave state, the dream state, REM sleep. In theta, your thoughts slow down to 4 to 8 thoughts per second. This is where super learning happens. Kids and artists experience a lot more theta activity in their brains. Emotional integration and release also happen here, and structures in the brain change. It’s here that some people sometimes have random thoughts or see images. A person in theta may see colors or visions or hear the voice of a person talking yet at the same time not hear this voice. It’s where you being to enter the gap of nothingness.