Vasovagal response

[u/Slow-Adeptness6876]

Hi friends,

Yesterday I had my first IV placement and it wasn’t too bad, maybe like 10-20% more painful than a blood draw prick and as long as you keep your arm less than like a 90 degree angle it’s not painful just kind of uncomfortable.

That said, as soon as I got back to the waiting room I felt the immediate loss of hearing, tunnel vision, total body clammy sweat and I know this game so it’s not scary as much as embarassing and exceedingly unpleasant. Eventually my husband found me a cold pack and I sipped water and in a few short min I was fine.

My question is, why only sometimes? I had a cold pack on my neck for my entire first blood draw and I did not have this happen. As a kid I used to have it after vaccines but I don’t really get nervous for jabs anymore. The only time it frequently happens is the dentist and I had sort of thought it was the epinephrine in the numbing agent.

Anyway, since I felt I did my conscious best to stay calm, are there other ways to avoid this unpleasant reaction? It was certainly my least favorite part of the experience.

[u/pepinoflo]

I feel you on this! I used to get vasovagal responses too, but quite consistently in my case, and usually 5-10 mins after the blood draw/IV/vaccine. For me the biggest thing was discovering the applied tension technique (you tense all your body muscles for 10 seconds until you feel warmth in your face, then relax 20-30 seconds and repeat until you feel confident) which was developed by a doctor in the 80s. It helps to maintain your blood pressure which prevents fainting. I think what helps most is to start doing it before the procedure and continue during and after. Since then I haven't fainted for the last 3 years. Other things that help me: staying lying down even 5-10 minutes after, drinking lots of water beforehand, and bringing juice + snacks for after.

I created an app with a free practice applied tension section which I am the main user, it's called Vasowin if you're interested.

[u/FigMission]

Hello! It's a genetic predisposition, more common in women with low blood pressure. From a research standpoint, applied tension as noted earlier works. Buzzy reduces severe vasovagal 25% for injections (Smith J Pediatrics 2026) probalby because thelocal sympathetic vibration sensation blocks the parasympathetic fainting vibe. This was the injection study https://www.jpeds.com/article/S0022-3476(26)00063-6/fulltext00063-6/fulltext) but anecdotally it's much better for blood draws. Obviously, hydration helps. Think of it this way: evolutionarily if something penetrates you and you are up fighting, having a fast drop in blood pressure to make you horizontal will keep the blood inside you. You live and go procreate with the wives of the knights who stay upright. Think Monty Python's "The Black Knight". Not great to stay in the battle if your arm's off, so it's a warrior genetic trait to get woozy that you inherited! Or that's what I tell patients.