The reason why you passed out during a blood draw at the doctors office today is a result of a vasovagal reaction, which is actually a very common reflex where stress, pain or even the sight of a needle causes your heart rate and your blood pressure to suddenly drop.
The brief drop of your heart rate and blood pressure reduces blood flow to your brain and leads to fainting.
If you didn't eat enough food or are malnourished or underweight it can also lead to the passing out during a blood draw.
I once passed out during a blood draw when I was having issues keeping up my weight due to anxiety and I was way underweight and even malnourished and I didn't even realize it.
I had my blood drawn and then suddenly passed out and the doctors gave me a banana, Coca Cola and placed ice on the back of my neck.
My vision also went blurry and I couldn't feel my legs for a bit and had to stay in the doctors office for a few hours while they watched over me.
Other common triggers of passing out during a blood draw include a fear of needles, seeing the blood or the medical equipment, having low blood sugar from skipping a meal or fasting, not drinking enough water beforehand and even experiencing pain or discomfort from the poke of the needle.
Some things that can help prevent you from passing out next time from getting your blood draw include.
Laying down for the blood draw if you feel woozy easily.
Eating a small snack and drinking water before you have your blood drawn, unless told to fast beforehand.
Looking away from the needle and talking to the staff to remain calm during the blood draw.
Tensing your leg and arm muscles during the blood draw to keep your blood pressure up.
And telling the doctors ahead of time that you tend to faint during a blood draw.