If you are practicing astral travel early in the morning as you come out of sleep, then you should already be in a fairly tranquil state. However, you will still need to further relax so the body can fall asleep again while your mind stays awake. This is called the hypnagogic state.
Relaxation and brainwaves : Relaxation may be better understood by taking a look at the various categories of brainwaves that manifest during our various activities (see tables below).
Gamma (38-90 Hz) : High awareness, strong perceptions, lucid dreaming
Beta (12-38 Hz) : Usual problem-solving, waking, everyday state
Alpha (8-12 Hz) : Slower brainwaves, relaxed and creative state, light meditation
Theta (4-8 Hz) : Deep relaxation and meditation, dreaming, out of body experiences
Delta (0.5-4 Hz) : Very slow brain activity, deep sleep, regenerative state
Lambda/Epsilon (less than 0.5 Hz and higher than 100 Hz) : Multidimensional awareness, mystical consciousness.
Most people spend the majority of their waking hours in a beta (12-38 Hz) state of mind. To experience astral projection consciously, you need to lower the speed of brainwave frequencies to theta (4-8 Hz). You may achieve this by deeply relaxing your body and mind.
