Discussions that mention potassium

High & Low Blood Pressure board

Low blood volume and the kidneys just not holding the water no matter how much salt you use. I have the same problem, salt and extra fluids does nothing - I still have blood pressure ranging from 50s/30s to 90s/60s. 70s-80s/40s-50s being typical unless I take medication. Also certain hormones during menstruation can drastically affect blood pressure in some individuals - though generally if there's something else going on.

I have also been diagnosed with neurocardiogenic syncope - also called neurally mediated hypotension. Because of this my body gets the wrong signals and my blood vessels dilate instead of contract to keep my blood pressure regulated. This makes it pool in my hands and legs when I sit and stand. People that have this, connective tissue disorders, and certain types of neuropathy all can get blood pooling. The result is less blood get circulated, and in my case there's not a normal amount of blood to begin with.

If standing up, and remaining standing, makes you feel light headed you should consider looking into this. You may also want to make sure your kidneys are functioning properly - some people's don't produce the renin levels needed so they have the blood volume issues. A CBC, potassium, iron, and B12 levels should be checked if your doctor hasn't done so already.
Be careful in the heat, don't let yourself get dehydrated, and be careful when you stand up.