Yoga Nidra

Yoga nidra or "yogi sleep" is a sleep-like state which yogis report to experience during their meditations. Yoga Nidra, lucid sleeping is among the deepest possible states of relaxation while still maintaining full consciousness. 

The practice of yoga nidra relaxation has been found to reduce tension and anxiety. The autonomic symptoms of high anxiety such as headache, giddiness, chest pain, palpitations, sweating, abdominal pain respond well.

Yoga nidra refers to the conscious awareness of the deep sleep state, referred to as "prajna".