Its not the loss of blood circulating in your system that lowers your blood pressure. An average human has 4.5 to 5.5 L of blood, an average blood draw is like… 10 ml, 0.2% of all your blood.
The vasovagal response is somewhat common during blood draws, basically, its a stress/fear/anxiety response, your nervous system iniates it and then your heart rate slows and your blood vessels dilate, widen, and this makes your blood pressute drop… its not the actual blood loss itself causing your blood pressure to tank, its all the other parts of your circulatory system changing how they regulate your blood pressure.
Its pretty common to experience this effect mildly, and temporarily.
But… if you regularly feint from routine blood draws… that is actually potentially concerning, as it may indicate you are anemic, significantly malnourished or dehydrated, have circulatory system blockages, or just generally have significant hypotension, or have some other underlying problematic, very often treatable condition.
Again, routine, regular, every time you get a blood draw, you feint, completely black out?
Thats different than you get a bit woozy and then in 5 minutes you’re fine.
Ironically, you’ll need blood tests to check for a lot of the most common indicators of the most common things that cause routine feinting from a blood draw… you gotta get that bloodwork to start pinpointing root causes.
But it could also be that you just generally have very high stress levels, or some other mental condition.
Or it could be side effects from drugs you are on, including common SSRIs and other mental health drugs, actually contributing to your vasovagal response being so severe that you regularly feint during blood draws.
empireOfLove2@lemmy.dbzer0.com 1 month ago
Yup. I guess the medical term is “Vasovagal syncope” but the vagus nerve does a lot of stuff..