I was helping someone move a refrigerator down steps and it slipped while I was holding a sharp corner and it sliced my finger and there was continuous blood flow. Soon after, I started feeling light-headed and was shaking and felt like I was about to pass out or have an attack, but I could not allow myself to appear weak, so I fought against it mentally and I got past it without anyone observing any signs. Did I avoid circulatory shock? Did pure mental dedication allow me to surpass such a thing?


2 Answers 2


Is it possible to stop yourself from going into shock?

There are different types of shock: hypovolemic, cardiogenic, anaphylactic, septic, neurogenic, etc.

Can you prevent yourself from going into shock by virtue of pure willpower? No. You cannot override the body's reactions to decreased oxygen to the brain any more than you can will yourself out of the flu.

The early signs of hypovolemia (blood loss), though, can be confused with those of vasovagal syncope (simple fainting). Both involve dizziness/lightheadedness, cool or clammy skin, and a decrease in blood pressure. However, with hypovolemia, your heart rate increases to compensate for the lowering of blood pressure (which eventually leads to shock), whereas with vasovagal syncope - which can occur with sudden fear - your heart rate drops, which is what causes your blood pressure to fall.

Passing out due to blood loss depends in part on how rapid the blood loss is (the more rapid, the earlier on might pass out) and the volume lost. To lose enough blood to pass out, a healthy, normally hydrated person would need to lose about 2 liters of blood (or 20% of one's blood volume); maybe 1.5 liters if it happens quickly enough.

Regardless of whether it happens slowly or quickly, if enough blood is lost, shock will ensue. No amount of willpower will stop it.

Interestingly, the sight of blood or having your blood drawn are frequent triggers of vaso-vagal syncope.

What you experienced is commonly called pre-syncope: the feeling of lightheadedness as though one might blackout, but consciousness is preserved.

Vasovagal syncope
Hypovolemic shock

  • $\begingroup$ +1, but I have heard an MD telling that she would faint when blood loss occurred with herself/her loved ones while she wouldn't faint when performing surgery in the OR. I guess I have the same thing - I fainted when a doctor drew blood from my baby, but I am totally sure I could draw blood without problems from someone else I didn't know. I don't faint when they do it to me either. There is something going on in terms of will power / professionalism /emotional involvement that may keep one from fainting. $\endgroup$
    – AliceD
    Commented Oct 14, 2015 at 23:13
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    $\begingroup$ There was a fellow medical student in my class who would faint at the site of anyone's blood, his or someone else's, every. single. time. Unfortunately, the profs had no sympathy, and we witnessed him pass out during most of our hematology labs where pinpricks were needed. The thing with you is emotional - you are more concerned about your child than yourself. That's not at all uncommon in parents. We often tell parents to avert their eyes when doing bloody procedures on kids. (My adult friend passed out when I was ministering to her daughter's cut in my kitchen. And she's stoic.) $\endgroup$ Commented Oct 14, 2015 at 23:21
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    $\begingroup$ @AliceD, Fainting due to a small loss of blood (50 mL?) during blood drawing is not caused by shock, but by a vasovagal syncope triggered by pain and looking at blood. In this reaction, the vagus nerve temporarilly slows down the heart rate, which causes a drop of blood pressure and hence fainting. You may be able to learn to prevent such a reaction. In hypovolemic shock, you lose a lot of blood (700 mL+), which again causes a drop of blood pressure. You can't convince yourself that you did not lose blood; still your psychological reaction to blood loss may aggravate or postpone shock a bit. $\endgroup$
    – Jan
    Commented Oct 29, 2015 at 15:59

I seriously doubt you lost 750mL of blood, the 15% where they wouldn't even treat you, according to your linked article, which is the equivalent of a full bottle of wine, from that cut. Even if you had sliced your finger off completely, I doubt that you would have lost that much blood. You would need to sever an artery...

750mL is less than two units of blood that you would give donating blood, and they are hardly concerned with putting anyone into shock at a blood drive.

You likely had a vasovagal response (syncope) to the sight of the blood.

Now if you were in a car accident and the guard rail had impaled you....


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