Deep trance is a healing state, because the body's energy or qi flow much better. Relaxation is a healing state for the same reason. Put trance and relaxation together, you have a powerful healing potential. There is no limit to how deeply you can go into trance or relaxation. That is to say, one can always relax deeper, one can always let go of conscious mind attention still more. Sleep is a healing state, but not as effective as deep trance because the mind is very active during sleep and will disturb the healing energy flows of the body.
The energy or qi related to the phsycial body cycles in a pattern, often known as the micro-cosmic orbit, up the back, down the front. Its cycling in and about channels sometimes called nadis. The channels themselves cycle like ropes being pulled around and around.
The less the conscious mind is active, the better and stronger the qi can cycle. More thoughts mean more disruptions. Also, painful emotions constrict energy flow. Positive emotions allow the energy to flow easier. Selfish, ego-based thought restrict energy flow. Selfless, equanimity allow energy to flow easier.
Deep trance is something to be practiced and mastered, and you will always have access to energy healing states. It can be learned through hypnosis, by entering the states the body will eventually remember the access and it will become natural.