Discussions that mention potassium

High & Low Blood Pressure board

90/58 isn't that bad, I believe anything under 90/50 is considered very low.

famnd's advice about the 16oz of fluid may or may not affect you since you are that low.
I can drink 30oz or so and have absolutely no blood pressure increase. Be careful about increasing salt, if you do not have low blood volume this won't help you very much and can result in you losing too much potassium. Increasing salt can also cause headaches in some people.
Caffeine can raise blood pressure but it also dehydrates you which will cause it to fall later - so you'll have to play catchup a bit on fluids to prevent that.

Be careful when getting up, do it slowly so your body has time to adjust your blood pressure. Standing up too quickly, especially from lying down can result in dizziness or even falling.

My blood pressure ranges from 50s/30s supine to 106/70s standing -with everything in between. When it's 60s or 70s/50s while standing then there's a problem.