>>40619912
I can only share my experience, but not directly with the GNM thing, just the general idea of stress and anxiety causing physical ailments.

Many moons ago I asked for help here because at the time it seemed like my entire body was falling apart.
Various pains, inflammations, infections recurring, neuropathy etc. etc. and I legit felt like dying.
One anon recommended something similar, or maybe even this exact thing to me at the time and I followed it to an extent.
There was also a book, maybe this one "The Body Keeps the Score: Brain Mind and Body in the Healing of Trauma" so there is more than just one person claiming it.

I worked through my past, even went back and talked with the people who affected me negatively in childhood, to figure out the cause and effect of events in my life.
Turns out my whole family is a long line of trauma from abuse and they just perpetuated it.
I let go. I slowly accepted what is curable and what isn't (tinnitus) and now it doesn't bother me either.
A lot of the pain I had from herniated discs, neuropathy, inflammation etc. went away as I progressed.

Your mind really affects a lot more things than medicine often does.
If you are sick, of course go to a doctor, but focus on the healing process.
Focus on how your body is going to do the healing and fixing and then support the process both in mind and body.
I can't give you any specific mental exercise as I didn't follow a system, just the general idea as I saw fit.
The cause and effect things is important.

Take note of what truly causes your ailment.
Sometimes stress tightens certain muscles that might as well feel like something else. For example, stress can effect your pelvic floor which can cause chronic prostatitis, which will then produce UTI like symptoms.
The UTI feeling will keep you in a constant cycle of stress and tension and it perpetuates until a real infection manifests from the circumstances.
Praying helped a bit. Even if I'm not religious.