Muldoon, Sylvan - Interaction between spiritual and physical
Type of Spiritual Experience
The functions of the spiritual body still control the physical body, so the heart beat and the breathing rate affect the physical. If you breathe differently then you could break the trance state, because you are changing the conditions needed. The calmer the state and the less laboured the breathing the less the pull will be of the physical because the reasoning functions are more effectively stilled and the will more subdued. Furthermore, if you do something daft like hold your breath when out of body, you could actually do yourself great harm physically.
A description of the experience
Sylvan Muldoon and Hereward Carrington – The Projection of the Astral Body
So, too, will the heart-beat affect cord-resistance. The more calm the breathing, the less will be the cable-pull. If conscious, strong, deep breaths are taken by the phantom, when within cord-activity range, the pull on the cord will increase often even to the point of drawing the astral entity toward, or even into, the physical. I have tried this and know it to be a fact. On the other hand, the speedier and stronger is the heart-beat, the greater the cord-resistance..............
Although suspending the breath, while consciously exteriorised, will weaken the cable resistance, it is not advisable to practise it, to enable one to get out of cord-activity range; for, as I have pointed out before, the physical would become endangered for want of oxygen, as it is already in a weakened condition.