Physiological conditions ,sensation is something burning or itchy
For a long time, the standard for "normal" blood pressure was 120/80. The current thinking is that a more healthy pressure is actually 110/70. 106/64 is a little lower than the norm but may be totally normal for you. If you become dehydrated it can lower your blood pressure and if your blood pressure goes too low it can cause feeling faint or passing out. If it's never been an issue and your MD doesn't have a problem I wouldn't worry.
Answer:
It takes very little to to lose oxygenated blood to the brain.
Explanation:
Breathing does two things: Intake of oxygen and removal of carbon dioxide. If there is a respiratory emergency, for example, and overdose victim stops breathing, the carbon dioxide can build up, damaging parts of the brain, leading to forgetfulness, headaches, nausea, amnesia, fainting, brain damage, both minor and major, and in extreme cases, death.