At what point is blood pressure dangerously low? I tend toward low blood pressure anyway. Sometimes I experience dizziness, weakness, and on rare occasions, fainting. I am on a low dose beta blocker to treat SVT, and my doctor recently raised my dose. I am noticing that I have had dizziness and weakness most of the time, since the increase; although, it hasn t been severe enough to make me black out. I have a blood pressure cuff, but it s not consistent, in that I can get several very different readings within a few minutes, so I don t think it works right. I just go by how my body is feeling. Other than calling my doctor in the morning, do you have any recommendations for now?