How can someone with low blood pressure handles...

How can someone with low blood pressure handles fasting?

you should exclude the presence of low body cortisole which may be caused by addison disease which should be treated by giving hydrocortisone and then you can fast and low blood pressure may be due to not drinking enough water after breakfast to compensate for the fluid loss during fasting which can be solved by drinking enough water and the cause may be taking high blood presure medicatin and in this case the doses of the drugs should be modified and if low blood pressure cause syncope or falling then you should not fast to prevent any the complications

How to diagnose low blood pressure

you should be assessed by the physician to measure the blood pressure to detect its value and you can has blood cortisol level done to exclude its deficiency and you should has ADH level done in the blood

What are the causes of low blood pressure 

low cortisol
low ADH hormone
dehydration

advice

you should be assessed by the physician to do the lab test and provide the treatment