If you feel lightheaded when getting out of bed in the morning, standing up quickly, or getting up out of a bath or hot tub, you may very well have low adrenal function, and including more salt in your diet could be helpful. (ericbakker.com)
However, when this process is happening too quickly, dizziness can occur, or you may feel lightheaded when you stand up from a sitting or prone position. (greensmoothiegirl.com)
I started feeling lightheaded after about 20 minutes in the shower, and I got out. (barbarahotelling.com)