Why do needles make some people faint?
Adam’s Journal
I know people who nearly pass out at the mere sight of a needle. What causes this? Is there a way to make it stop?
Dr. McEver Prescribes
When an environmental trigger like the sight of blood or a needle causes fainting or near-fainting, it’s called vasovagal syncope.
The condition is caused by a temporary loss of blood flow to the brain. While it does not cause lasting health problems, it can lead to injury by falling. And, of course, no one likes feeling faint.
The condition begins in the brain, where the part of your central nervous system that regulates heart rate and blood pressure overreacts to a trigger. Those triggers can be visual like the ones you mentioned, but things like standing for long periods of time, extreme heat and dehydration, and intense fear or pain can also kick the nervous system into overdrive.
This overstimulation causes blood vessels to dilate, especially in the lower extremities, and the heart temporarily slows. With blood pooling in the legs and the heart unable to pump it quickly, fainting can occur.
While the loss of consciousness can be sudden, it’s generally preceded by warning signs. Symptoms often include clamminess, dizziness, blurred or tunnel vision, nausea and ringing in the ears.
Vasovagal syncope is most common in children and young adults. For those who don’t outgrow it, management depends on the underlying cause. Most often, it involves avoiding triggers and recognizing symptoms.
While you might not always be able to prevent a fainting episode, lie down and elevate your feet as soon as you sense a warning sign. Gravity will help to restore the blood flow to your brain and likely prevent you from losing consciousness.
McEver, a physician-scientist, is vice president of research at the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF’s senior vice president and general counsel and interim president. Submit your health questions for them to contact@omrf.org.