Maybe you scream when you see something scary.
Perhaps you laugh.
But have you ever fainted?
If so, it wouldn’t be uncommon.
Lots of people who attended the recent Broadway show “1984” found themselves passing out during some of the play’s torture scenes.
In fact, Robert Icke, the play’s co-director, has told media outlets that audience members have been fainting since the show started running a few years ago in London.
Even though theater attendees are warned that the play contains “graphic depictions of violence and torture,” Icke says the scenes aren’t vivid.
He believes the fainting occurs because of the audience’s imagination.
Still, why such an extreme reaction?
“When someone sees something frightening, disgusting or scary, they activate the emotion centers in their brain, and then that sends a signal to the brain stem, which connects the brain and the spinal cord. And when those connect, you get signaling to the cord to dilate the blood vessels and signaling to the heart to slow down. That’s when fainting happens,” Dr. Safwan Jaradeh, neuromuscular neurologist and neurophysiologist at Stanford University in California, told Healthline.
He explains that normally when blood pressure drops, the heart rate should accelerate and vice versa.
But in cases where people faint, the signaling gets mixed up.
“The blood vessels dilate and the heart rate slows, and as a result the combo of drop in blood pressure and slowing of the heart rate causes one to faint,” Jaradeh said.
This type of fainting is referred to as vasovagal syncope — the most common cause of fainting.
It often occurs at the sight of blood or needles or when someone is scared, dehydrated, or overheated.
Paradox of ‘fight or flight’ response
While it may seem that the body’s “fight or flight” response should protect us from fainting, that’s not always the case.
“With some people as part of the ‘fight or flight’ response, their heart rate accelerates or races a little too much. And instead of coming down slowly like it normally would, the brain jams the brakes on too quickly. So the heart goes from beating rapidly to slowly and you faint,” said Jaradeh.
This is called reflex syncope.
Dr. Sue Corcoran, a cardiologist at Baker Heart and Diabetes Institute in Australia, said “fight or flight” plays a part in another way, too.
“If we are scared or anxious, we release adrenaline (epinephrine), which is one of our ‘fight or flight’ hormones. It acts to help us run away from bad things. One of the ways it does this is to send blood to the legs. If we don’t run away (because our stress is emotional not physical), it adds more blood going to the legs and less to the head and makes someone who is prone to fainting more likely to do so in that circumstance,” Corcoran told Healthline.
This may also be the case with the sight of blood, which occurs in 3 to 4 percent of the population, notes Corcoran.
“People who faint at the sight of blood may also faint with pain triggers such as an injury or vaccination. The mechanism for this type of fainting remains elusive. It begins with an increase in heart rate and blood pressure, followed by a fall in blood pressure and heart rate at the time of the faint. People often feel nauseated before they faint (thought to be due to the back of the brain not getting enough blood supply) and may vomit,” Corcoran said.
Fainting can occur quickly for some people, particularly with pain triggers, she added.
“Some thoughts are that it may be a combination of the effect of epinephrine, together with the physiological changes seen with an emotional response to fear or disgust that result in this pattern of heart rate and blood pressure changes,” Corcoran explained.
How dangerous is fainting?
Up to 50 percent of the population will faint at some time in their life, said Corcoran.
This can be intermittent and temporary as in the case of vasovagal syncope or due to blood pressure regulation problems as is the case with 70 percent of people who faint.
“Fainting due to a blood pressure regulation problem can be serious if the person faints in a dangerous situation, like while driving or if they fall and injure themselves. But the condition itself is not life-threatening,” Corcoran said.
Fainting is serious in about 10 to 15 percent of cases that are due to heart conditions, such as abnormal fast or slow heart rhythms or conditions that obstruct the flow of blood from the heart (e.g., aortic stenosis and hypertrophic cardiomyopathy).
Cause for concern is fainting that occurs during exercise or when lying down, or in those with a known personal or family history of heart disease.
Fainting runs in families
Although vasovagal faints are common, it’s still unknown exactly why some people faint and others don’t.
“Most researchers have found that people who are prone to fainting pool blood more in their legs and in the pelvis, so when they stand, more blood goes to their legs and less to their head. They are more likely to faint if the weather is warm, as our body loosens blood vessels to send blood close to the skin to try to cool us down. But this also means blood vessels aren’t tightening as well to return blood to the heart to pump it around the body,” Corcoran explained.
Jaradeh added that those who experience vasovagal fainting most likely have a genetic predisposition, even though no specific gene has been identified.
“If you have a family history, you’re more likely to have it,” said Jaradeh. “If you ask your parents, most likely one will say they had a fainting spell from donating blood, camping in the heat, or getting scared.”
He also points out that vasovagal fainting peaks during childhood and adolescence, becoming less prevalent with adulthood.
“Patients who have this phenomenon of fainting when they see blood or during a scary movie usually do fine in their 20s and 30s and 40s,” said Jaradeh.
However, he adds that long-term studies show a bit of a peak in people in their 50s.
“It’s usually when people are sick or around a surgery. For instance, if someone in their 50s has surgery for a hernia or has to have their appendix taken out, they are more likely to faint in the first 48 to 72 hours after the surgery because of stress,” Jaradeh notes.
He points to health and medications as potential reasons for the peak.
“We are pretty healthy and robust, and our system is very mature in our 20s, 30s, and 40s. And then as we get older, the system becomes too relaxed and lets down if you will,” said Jaradeh. “Also, as we age, we are more likely to be on medication. If you have high blood pressure and are on medication for that, you are prone to dilate your blood vessels, so if you are stressed or overheated or have surgery, you’re more prone to fainting.”
What to do if you feel faint
If you’re prone to vasovagal fainting but still want to embrace scary things, Jaradeh said there are a few things you can do before watching a scary movie such as “Jigsaw” or going inside a Halloween haunted house.
- Hydrate and eat something salty. “They expand your plasma volume so even though you dilate the blood vessels and slow down the heart when you’re scared, you’ll be able to keep from dropping your blood pressure,” said Jaradeh.
- If you’re sitting down, bend forward and tighten your legs and buttock muscles. “Tensing your leg muscles makes the blood stay above your waistline, and as a result you don’t pass out,” notes Jaradeh.
If you can’t sit, squatting down will also force blood from the legs and stomach to the head.
In cases where you witness someone faint, lay them down flat immediately. Then elevate and cross their legs. “This will return blood to the heart and may stop the faint,” Corcoran said.
Take note that some people may twitch when they faint, especially if they faint sitting up.
“This doesn’t mean they are having a seizure. The twitching is usually the body’s attempt to come back to,” said Jaradeh. “The key is once you lay them down flat, it should go away. If the twitching continues, then put them on their side because they may be having a seizure. Then call 911.”