Increasing your fluid and salt intake to treat low blood pressure

http://www.nhs.uk/Conditions/Blood-pressure-(low)/Pages/Treatment.aspx

Increasing your fluid and salt intake

Dehydration can cause low blood pressure. This can be easily treated by increasing your fluid and salt intake. Ensuring you drink enough fluid will help by increasing the volume of your blood, which increases your blood pressure.

If you have low blood pressure, you may benefit from having more salt in your diet. Your GP can advise how much additional salt you need and whether you can add salt to your usual food or take salt tablets. Don't add extra salt to your diet without seeing your GP first.