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.
Someone with a systolic pressure of 120 and a diastolic pressure of 80 has a blood pressure of 120/80, or 120 over 80.. Normal blood pressure is lower than 120/80. Low blood pressure does not have a specific number where it is too low. Most doctors consider blood pressure to be too low when it causes symptoms or drops suddenly. In general, low blood pressure symptoms happen when blood pressure is less than 90/60.