JUN 08, 2016 6:14 AM PDT

Why does the sight of blood make some people faint?


Have you ever wondered why some people faint at the sight of blood? A fear of blood is classified as a phobia, which is an intense irrational fear of something that causes your body to react by going into fight or flight mode, and approximately 3-4% of people have a blood, injury, or injection phobia. But unlike other phobias, phobias of blood, injury, and injection can actually cause a person's blood pressure and heart rate to go up and then suddenly drop, which can cause them to lose consciousness among, other symptoms.

A nerve called the vagus nerve causes a drop in blood pressure when it is triggered by certain external stimuli like pain, dehydration, or sudden fear, among other causes. Scientists think that this nervous system reaction may be an evolutionary trait that lowers blood pressure at the sight of blood to prevent bleeding to death.

Researchers have found an effective way to cure certain phobias. The phobic person must tense his or her muscles and then slowly be exposed to whatever they are afraid of little by little. Tensing up stops the drop in blood pressure from happening. In the case of a blood phobia, they show the phobic person a spot of red, and then a larger spot of red, then a picture of blood, and finally blood.

Source: Geobeats
About the Author
BA Environmental Studies
Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
NOV 06, 2020
Space & Astronomy
300 Million Planets in the Milky Way May Be Habitable
NOV 06, 2020
300 Million Planets in the Milky Way May Be Habitable
Researchers have found that there could be at least 300 million habitable worlds in the Milky Way galaxy. This could mea ...
NOV 07, 2020
Space & Astronomy
Scientists Detect Origin of Fast Radio Burst in Milky Way
NOV 07, 2020
Scientists Detect Origin of Fast Radio Burst in Milky Way
Scientists have identified a burst of cosmic radio waves- intense flashes of radio emission that last just a few millise ...
JAN 21, 2021
Plants & Animals
Western Monarch Migration Near Extinction
JAN 21, 2021
Western Monarch Migration Near Extinction
Earlier this week, the Xerces Society for Invertebrate Conservation reported that the western monarch butterfly populati ...
JUN 21, 2021
Space & Astronomy
Scientists Detect Signatures of Life on Earth Remotely
JUN 21, 2021
Scientists Detect Signatures of Life on Earth Remotely
An international team led by researchers from the University of Bern in Switzerland and the National Centre of Competenc ...
JUL 22, 2021
Space & Astronomy
Telescope Riding a Balloon Could Replace Hubble
JUL 22, 2021
Telescope Riding a Balloon Could Replace Hubble
The Earth's atmosphere often muffles views from ground-based telescopes when observing space. Now, a research c ...
OCT 29, 2021
Health & Medicine
Can Playing Tetris Help Patients with PTSD?
OCT 29, 2021
Can Playing Tetris Help Patients with PTSD?
Intrusive memories are one of the most harmful symptoms of Post-Traumatic Stress Disorder, or PTSD. Intrusive thoughts a ...
Loading Comments...