Neuron Structure. Your brain is made of approximately 100 billion nerve cells, called neurons. Neurons have the amazing ability to gather and transmit electrochemical signals -- think of them like the gates and wires in a computer.
Most doctors will only consider chronically low blood pressure as dangerous if it causes noticeable signs and symptoms, such as: 1  Dizziness or lightheadedness. 2  Nausea. 3  Fainting (syncope)  Dehydration and unusual 1  thirst. Dehydration can sometimes cause blood pressure to drop.  Lack of 1  concentration. Blurred vision.  Cold, clammy, pale skin.
Think about yourself, and what you normally run. If you are normally 140/80, and you get a result like 90/50, that would be low for you. Low numbers are especially concerning if you feel symptoms from your blood pressure being low, like dizziness, fatigue, or fainting (often called syncope). If this is happening to you, your blood pressure may be too low.