I'm using my BP machine as a guide along with knowledge of my HTMA's, to monitor my magnesium intake. Because Magnesium can lower Sodium.. Although I haven't gotten low blood pressure yet, I did get down to 99 (crampy feet, ringing ears), and just didn't feel good. So, if I see that my BP is falling too far down again, then I know to lay off the Magnesium a bit, take an Adrenal and a bit of salt. So far, it seems to be working for me because I feel great..