Chronic contraction of the blood vessels due to long term postural, psychological ( mental, ideas, thoughts, obsessions, unrealistic strong desires that can not be put in action, inflexible ideas and ways of thinking, excessive stubbornness, etc), physiological - muscular tension habits and external factors, will change some functions in the vital energy circulation in the body thus building energy blocks and opening the door to a series of diseases like for example: arteriosclerosis, stroke, circulatory problems and poor circulation and many other issues including lymphatic problems. Some cancers can result from such chronic, static buildup on an energetic level in the body. When things don't or stop flowing, things stagnate, when there is stagnation there eventually will be a lack of life. 

Nobody has yet been able to prove the existence of a universal life force energy in a laboratory and it will never happen because they are looking for something that is already present and has always been and it will always be. It is always present in us and around us, there is no effort to be made to get to it because it is already here. To convince yourself of this fact is just to experience it and see its effects and so you will prove to yourself of its existence, no need to wait for some scientist  in a lab coat. 
This universal life force energy is also what some people call universal consciousness. That is why we are never separated from the universe and its energetic information. Every cell and atom is a universe in itself, nothing is separated and so we can plug in and absorb energetic or life force information and this is used for healing.
Just let the life force energy do the work, there is nothing you can do but just step out of the way. relax, there is no magical pill you can take to fix you. The body heals itself, you just have to step aside and let the natural or universal intelligence of the body which is the life force to do the healing.
Somehow a lot of people say that they know this and they understand it but somehow when the shit hits the fan the first thing to do is put ourselves in the hands of some doctors and bunch of their tests ( I wander where would doctors be and how competent would they be without relaying on all their tests and equipment). We have become slaves to our habits, conditioning and believes. How hard and difficult is to change the ways we are doing things when we get sick ?....it must be very difficult indeed because since the age of about  3 years old we are told that the guys in the white coats, the doctors are the ones that will fix us and take care of our health. 
My friends, healing has to do with becoming free, breaking  the chains of conditioning and habit and opening up and accepting the wisdom of our body and that which is running and keeping it alive, that being the life force energy. 
It takes guts and courage to do the following:..Do nothing, rest,...the body heals itself.  Healing has nothing to do with medicine.