Esoteric writings from multiple cultures throughout time have described layers of our form as subtle bodies. The ancient Egyptians recognized not one, but a set of interrelated bodies that made up “us.” One of these is the astral body. It links the physical and non-physical worlds.
In the ancient Egyptian view, the bodies were organized as such:
Khu – divine intelligence
Sahu – called the immortal body
Higher Ka – or the higher Self
Haidit (Khaibit) – the shadow or unconscious Self
Lower ka – kind of like a double, containing the animating principle
Aufu – the physical body
Khat – the physical body minus consciousness
Ab – the heart of seat of conscious awareness, the seat of the intellect (notice it isn’t the brain)
Ba — the immortal soul
Ren – the name, often conceived as created by words
Sekhem – power, will 
In many other cultures, a similar organization of multiple layers of the conscious soul is outlined. The astral body, as imagined by the yogis and mystics of India, China, South America, and Tibet, is also called the astral field. It surrounds the etheric body and penetrates it. Some healers in ancient Greece and elsewhere call it the aura, while modern researchers refer to it as a low-frequency electromagnetic field.
Whatever the name given, this is the cultural cross-point between material and non-material, physical and mental, psychological, spiritual, and religious. It is the ultimate testament to a mind-body approach to healing, and also where we can begin to understand how our DNA can be affected by unseen forces. 
Modern medicine is highly Eurocentric and materialist, but we cannot truly heal the body without understanding that the body is not merely flesh, and blood, or combinations of mitochondria, cells, and proteins. The body, just as the ancient Egyptians described is a group of layers – energetic in nature – that make us, us.
The astral body is also most closely connected to the spirit world, and while Eurocentric, mechanistic medicine would like to dismiss the astral body as something dreamed up by a chemical cascade caused during a psychotropic experience, the astral body is every bit as real as the physical body as we understand it.  
Interestingly, many people that have an “out-of-body experience” report seeing cylindrical strands that mimic the helix-format of our DNA. We are likely seeing more of ourselves when we are in this altered state of consciousness, rather than experiencing something outside of us.
A recent scientific study, however, has proven that some people can have an out-of-body (which should perhaps be called an expanded-view-of-body) experience at will. This suggests that, contrary to the commonly held belief that the astral body is a projection of a chemically altered-brain, it is instead an expanded view of ourselves in a higher state of consciousness. 
As we learn to access this higher state of consciousness, healing can happen on more than just a physical level. Our mental, astral, and emotional bodies can also be healed, causing a cascade of positive experience throughout the physical body.
Healing on this level of consciousness is almost always much more profound than a simple “medical” healing such as taking a pill or herb, as it alters our conscious interaction with our holographic DNA, and communicates directly with the spiritual realm to adjust our vibration in time-space.
Because the astral body is able to reorganize at much more subtle levels than the physical (not relegated to cellular metabolism, etc.), astral healing allows a soul the ability to drastically alter the trajectory of one’s current life.
We actually travel to the astral realm when we sleep, and much healing takes place when we are there, but as we elevate our consciousness, even our dream-time, as the Aboriginals called it, can be intensely nurturing and supportive of positive change in our lives. 
In my book, The Power of the Elevation of Consciousness: Soul Restructuring, I discuss ways to access and heal the astral body so that these very changes can be observed.
 Ancient Egypt Body and Soul: Khat, Ab, Ren, Ka. . . http://www.reshafim.org.il/ad/egypt/religion/body_and_soul.htm
 Yoeli-Tlalim, R. (2010). Tibetan ‘wind’ and ‘wind’ illnesses: towards a multicultural approach to health and illness. Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences, 41(4), 318-324. doi:10.1016/j.shpsc.2010.10.005
 Winkelman, M. J. (2017). The Mechanisms of Psychedelic Visionary Experiences: Hypotheses from Evolutionary Psychology. Frontiers in Neuroscience, 11. doi:10.3389/fnins.2017.00539
 Astral Projection: Just a Mind Trip. (19, October). Retrieved from https://www.livescience.com/27978-astral-projection.html
 Voluntary Out-of-Body Experience: An fMRI Study. (n.d.). Retrieved from https://www.frontiersin.org/articles/10.3389/fnhum.2014.00070/full
 Waldram, J. B. (2013). Healing history? Aboriginal healing, historical trauma, and personal responsibility. Transcultural Psychiatry, 51(3), 370-386. doi:10.1177/1363461513487671