*Yammy* i have low blood pressure and it can make you feel lightheaded,had to have some blood taken yesterday, [have to have a pint taken every so often due to having too much iron] and my blood pressure was very low, they had me drinking loads of water and had to cross and uncross my legs,as that apparently helps the blood flow better, also can cause extreme tiredness
You can look at a blood pressure chart online if you google it
Also adding a bit more salt to cooking or meals helps low blood pressure, less for high BP