Is it OK to drive after fainting? Here's what new Canadian study says

·5 min read
Researchers have found people who have visited the emergency room after fainting are not prone to more car crashes when compared to other drivers. (Photo via Getty Images)
The UBC study has found no need to impose more driving restrictions on people who have recently suffered from first-episode syncope. (Photo via Getty Images)

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If you’ve ever questioned whether it’s safe to drive after fainting, a new study may put you at ease.

A study from the University of British Columbia’s faculty of medicine has found people who have visited the emergency room after fainting are not prone to more car crashes when compared to other drivers.

“I think the main message of our study is, fortunately, a very reassuring one,” Dr. John Staples, the lead researcher of the study and clinical assistant professor at the University of British Columbia, says. “Prior studies have suggested that syncope doubles, triples, or quadruples crash rates, but we actually found that after syncope the crash risk among patients visiting the emergency department with syncope is pretty similar to the crash risk among patients visiting the emergency department for other reasons.”

Researchers tracked the driving record of 9,223 people who visited an emergency department for fainting, medically known as syncope. They also examined 34,366 patients who visited the emergency department for a condition other than syncope.

The findings show that in the year following their ER visit, 9.2 percent of drivers with first-episode syncope were involved in a car crash compared to 10.1 percent of drivers who were involved in a car crash after suffering from a medical condition other than syncope.

This means the risk of a motor vehicle crash was similar in both groups.

Someone who is predisposed to fainting tends to have it happen again. (Photo via Getty Images)
Syncope, also known as fainting, happens when a person partially or completely loses consciousness. (Photo via Getty Images)

What is syncope?

Syncope, also known non-medically as fainting, happens when a person partially or completely loses consciousness. It typically results from a temporary reduction of blood flow to the brain.

There are several potential causes of syncope, including cardiovascular disease and neurological disorders. However, in some cases, no underlying cause can be determined.

There are three different types of syncope:

  • Vasovagal syncope can be caused by a number of triggers like dehydration, anxiety, emotional stress, hunger, or the sight of blood or a needle.

  • Postural syncope occurs when a person’s blood pressure suddenly drops right after they stand or sit up. It may be caused by dehydration or certain medical conditions.

  • Cardiac syncope is most often caused by a cardiac condition like heart disease or heart failure and arrhythmias.

Staples says vasovagal syncope is common and not particularly risky in the long term.

So can you always drive after fainting? Not if you suffer from rarer types of syncope

It’s the rarer types of fainting, like cardiac syncope, that can be dangerous and can pose a problem with driving.

“If somebody has a heart rhythm problem, which interrupts their heart from beating effectively and means that they're not getting enough blood to the brain and that's why they passed out, those people would be at high risk of cardiac arrest or other bad medical outcomes,” Staples says. “They'd also be at high risk of the syncope happening again, while they're driving and at risk of crashing. It's really that latter group of people that we apply most of our current driving restrictions to.”

Doctors can help determine if there is another serious medical issue causing you to faint. (Photo via Getty Images)
Doctors can help determine if there is another serious medical issue causing you to faint. (Photo via Getty Images)

There’s no need to impose 'additional driving restrictions'

Staples tells Yahoo Canada the motivation behind the study came from a young patient he saw almost a decade ago who suffered serious injuries from a crash. Doctors, including Staples, believed she crashed because she had fainted. The woman then asked the doctors if she should drive again and how long should she wait before getting back behind the wheel.

The B.C. expert looked at studies that were available back then and didn’t know what to tell the woman. That’s when he realized more research was needed.

“This was a decision that was going to be really important for her because, of course, she didn't want to drive and crash and injure herself or anybody else on the road, but not driving meant that she wasn't able to work. So, it was a big deal,” Staples explains.

The UBC study has found no need to impose more driving restrictions on people who have recently suffered from first-episode syncope. Staples says it doesn't necessarily mean that driving restrictions or alterations to driving behaviour aren't required after fainting.

“Already, physicians give advice to some patients who are at very high risk of syncope happening again, and therefore at very high risk of crashing," Staples notes. "We already give those people advice not to drive. And our study suggests that we're on the right track.”

Researchers also concluded that fainting can be a sign of more serious medical issues and recommend seeing a doctor if they've fainted.

The UBC professor says more research on fainting and driving is needed so doctors can ensure their advice is “better targeted to the patients of highest risk of recurrence and crash.”

“Our main conclusion is that what we're doing seems to be working and that means that more extensive driving restrictions after syncope aren't required,” Staples adds. “It also means that there's not a lot of evidence that current restrictions should be relaxed. It's more of a reassurance than a call for the scrapping of all syncope-related driving restrictions.”

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