I have only had blood taken twice in my life and I have fainted both times. When I have had my blood taken both times a very small amount of blood was taken simply for blood testing purposes. Now, I am not passing out for squeamish reasons of not being able to see blood, I am passing out because my body is not able to handle the loss of blood. However, my friends and family members have been able to donate an entire pint of blood in one sitting without passing out. I have never been able to understand how some people are able to lose such large amounts of blood with little to no effect while my body cannot handle losing only 3 to 10 milliliters.
First- we should establish what fainting is. Fainting is defined as “a sudden brief loss of consciousness and posture caused by a decreased blood flow to the brain.” Right before fainting, one’s blood vessels become dilated and cause low blood pressure. The low blood pressure in turn causes a decrease of blood reaching the brain, thus causing the affected person to lose consciousness. According to a an article done by De Anza College, approximately 150,000 people either faint or exhibit faint like symptoms after having blood taken each year.
According to an article by LiveStrong, some people are more prone to passing out after giving blood for prior health complication reasons. Diabetes, anxiety, irregular heartbeat, panic disorders, heart blockages, hypoglycemia and dehydration are all disorders directly linked to heart, endocrine systems and nervous system functions which can cause fainting. Furthermore, if you do not eat enough and stay hydrated prior to getting blood taken, you are more likely to pass out. However, I do not suffer from any of the above indicated disorders and have been sure to stay hydrated before giving blood. In the first instance I gave blood, I was able to eat beforehand. The second time I was not supposed to eat before giving blood. As a result, I can infer that my food intake is not a factor involved as both times I fainted, independent of whether or not I ate.
As a result- I am still left questioning why my body is so unable to handle blood loss. If I were to design an experiment in order to conduct further research, I would design an experiment in which I would study my blood cells and analyze the protein molecule hemoglobin in my blood. I would have doctors measure the levels of oxygen in my hemoglobin to see if it is saturating as well as it should be. If the hemoglobin is not saturating, it can leader to quicker drops in blood pressure. If it is the case that my hemoglobin is not being saturated with oxygen as quickly as it should be, then I may be able to conclude that a problem with my hemoglobin is the reason for my passing out.
Regardless of the reason, in order to prevent passing out after giving blood, the Red Cross has supplied some helpful tips for those preparing to give blood or have blood taken:
- drink 3 full glasses of either water or orange juice before donating or having blood taken
2. make sure to have eaten within the last 3 hours before giving blood
3. Tense and relax calf and thigh muscles while blood is being taken
Unfortunately, I am one of those squeamish people who has never come close to donating blood because the idea of seeing my blood leaving my body in large quantities stresses me out. To my knowledge, my problem is that I internalize the stress that I feel and my symptoms are psychosomatic (fast heart rate, shaking, etc.). In other words, I overthink the situation and psych myself out. So there could also be a mental aspect to answer the question at hand. As always, more studies to be done.
I have only has blood taken three times in my life, and each time can be categorized in the top 10 worse experiences of my life. Im not sure if it was the needle or just the fact that veins freak me out (yes i know that being afraid of veins is very odd). It may be beneficial for some hospitals to look up different methods of drawing blood in order to benefit those who have real trouble with it (for instance fainting).
I can relate a lot to this post. I am known for passing out whenever I have any interaction with a needle. I really dislike needles, so I tend to get really nervous before i get my blood drawn. I have Hypoglycemia. It is also known as low blood sugar. I faint if I don’t eat regularly, and it has happened so many times that I know when it is happening now. Two weekend’s ago I was coming home from Puerto Rico and was in the airport security line. I started to feel very light headed and was a little shaky, and my friend knows me well enough that she ran and got me cookies and a Gatorade to get my blood sugar back up and I was fine. I know this about myself, so now to prevent passing out when getting blood drawn I actually do exactly what you said at the end of your blog, but I actually ask to lay down while they do it. It helps a lot!
There is a physical examination for all the international students before we came to penn state. During the Physical examination, 3 tubes of blood were drew and I felt dizzy and weak that day, although it is not a big deal that people know this kind of phenomenon is quite common, but after learning from your blog, I know a lot about the mechanism inside.