Vaping even a single electronic cigarette can damage a person’s blood vessels, according to a new small-scale U.S. study.

The new findings, published in the journal Radiology, are adding to the growing but still fledgling body of research showing vaping isn’t as harmless as some have been suggesting.

There are few studies examining this, in large part because of how recently vaping has risen in popularity.

“We've shown that vaping has a sudden, immediate effect on the body's vascular function," the latest study’s author Felix Wehrli, a radiologic science and biophysics professor at the University of Pennsylvania, said in a statement.

“While e-cigarette liquid may be relatively harmless, the vaporization process can transform the molecules -- primarily propylene glycol and glycerol -- into toxic substances," he explained, also highlighting the additive, harmful effects of nicotine.

For the study, Wehrli and his colleagues recruited 31 people in their 20s and 30s who’d never smoked any cigarette -- electronic or regular. They each took 16 puffs from an e-cigarette with no nicotine.

Researchers then briefly cuffed one of the legs of each participant to restrict blood flow to a large artery in their thigh and they were given an MRI before and after smoking the e-cigarettes.

Normally, when the cuff is removed, the body tries to make up for the restricted blood flow, so the flow should be much faster.

But what they found was that after participants smoked, when the cuff was removed, the blood and oxygen flow was significantly slower to resume to normal speeds.

The new study suggests that with chronic use, the blood vessel damage could build up and increase the risk of heart problems.

"Clearly if there is an effect after a single use of an e-cigarette, then you can imagine what kind of permanent damage could be caused after vaping regularly over years,” said Alessandra Caporale, a post-doctoral researcher in the Laboratory for Structural, Physiologic, and Functional Imaging at U of Penn.

It’s unclear what is causing the harmful blood vessel damage because Wehrli’s team couldn’t determine if it was due to the aerosol, the artificial flavours or it’s because of what happens to the e-cigarette chemicals when they’re heated.

Although the team didn’t look at e-cigarettes with nicotine, the effects would be likely seen in those devices as well, researchers say.


Although e-cigarettes were originally designed to help wean smokers off traditional nicotine cigarettes, slick new marketing has made them appealing to a wider demographic of people, including teenagers.

Dr. Erika Penz, assistant professor of respirology and critical care at the University of Saskatchewan, who wasn’t involved in the study, told CTV News Channel that characterizing vaping as safe isn’t accurate.

“(Early on) we didn’t have a lot of evidence of what would be the short and long term effects of vaping,” she said. “But with time and higher use especially among our youth, we’ve seen it’s not an entirely healthy alternative.”

These latest findings could be troubling because of vaping’s popularity.

In Canada, 4.6 million people who were older than 15 said they tried e-cigarettes, with around 292,000 reporting smoking them daily, according to the University of Waterloo in 2017. In the United States, more than 10 million adults use them.

"E-cigarettes are advertised as not harmful, and many e-cigarette users are convinced that they are just inhaling water vapor," Caporale warned.

The growing call for more investigation was echoed when the U.S.’s Centers For Disease Control and Prevention recently reported that 94 possible cases of severe lung illness were tied to e-cigarette use.