Dehydration is very bad for someone with POTS We need to keep our blood volume up with hydration and salts (to retain the fluid) which also works to keep our blood pressure up and our heart rate down. This will help to decrease our symptoms. Ling along with water, you need to hydrate yourself with sports drinks that contain sodium and potassium. These are a must. Go to the main POTS website and read under... What helps... Increasing fluids and salts is addressed there. Good luck, Mary