Hi Jenna, poor circulation is suppose to be the good thing about this therapy it improves all circulation. At the beginning of the video he explains how lying inclined improves circulation. He also mentions that it's not like a hospital bed whereby you incline the top half/torso and leave the lower limbs still straight, you actually incline the whole bed from the floor/casters so you are sleeping flat but on an incline and he has found it helps BP.
As I stated I have just come across it and I am shocked at the difference it has made in my legs.
That's a really interesting interview. I have done this for many years, but I started because I had heart failure and the tilt really helped.
I suspect the effect for myotonia is somewhat related to steroid hormone production. The adrenals produce different amounts in different positions, so something at a different angle that completely horizontal may change the steroid production which in turn would alter potassium balance and reduce myotonia.