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 For the experiment, researchers asked 33 healthy nonsmokers to come
to a lab on different days to try an e-cigarette with nicotine, a
nicotine-free alternative, and a sham device that wasn’t a real
e-cigarette. Each time, participants wore a heart rhythm monitor to
assess variability in the time between heartbeats, an indicator of
increased adrenaline.
People experienced increased adrenaline only when they smoked
e-cigarettes with nicotine, and not with the nicotine-free
alternatives or sham devices.
Smoking traditional cigarettes has long been known to increase
adrenaline levels in the heart, and the current findings suggest
that nicotine in e-cigarette emissions does this too, said senior
study author Dr. Holly Middlekauff, of the David Geffen School of
Medicine at the University of California, Los Angeles.
“Inhaled nicotine delivered by e-cigarettes, traditional cigarettes
and other tobacco products (e.g. hookah) rapidly enters the
bloodstream and the brain and stimulates nerves that carry
adrenaline and the adrenal gland to release adrenaline,” Middlekauff
said by email.
“Perpetually increased cardiac adrenaline levels detected by
abnormal heart rate variability are associated with increased risk
for heart attack and sudden death,” Middlekauff added.
Big U.S. tobacco companies are all developing e-cigarettes. The
battery-powered gadgets feature a glowing tip and a heating element
that turns liquid nicotine and flavorings into a cloud of vapor that
users inhale.
Some previous research suggests vapor from e-cigarettes may be less
toxic than traditional cigarette smoke, but the electronic
alternatives still release chemicals that aren’t normally in the air
and the long-term health effects of the ingredients and flavorings
in e-cigarettes are unclear.
The current study doesn’t offer a complete picture of e-cigarette
safety or address the potential for health problems to emerge after
long-term use.
But it does reinforce concerns about the heart risks of nicotine,
the researchers note in the Journal of the American Heart
Association.
Epinephrine, commonly called adrenaline, is a hormone released when
something triggers a so-called fight or flight response in the
body’s sympathetic nervous system. Sudden fear or anger can lead to
a sudden release of adrenaline that may increase the heart rate and
blood pressure.
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The experiment also looked at what’s known as oxidative stress,
which increases the risk for hardening of the arteries and heart
attack. In blood tests, researchers didn’t find changes in markers
for oxidative stress after people used e-cigarettes with and without
nicotine.
One limitation of the study, beyond its small size, is that it only
looked at a small number of markers for oxidative stress.
In addition, because the experiment only looked at a single time
smoking e-cigarettes, it doesn’t offer insight into the long-term
health effects of these devices or suggest how the number of
e-cigarettes smoked during one occasion or over a single day might
impact the heart.
Even so, it makes sense that e-cigarettes and traditional cigarettes
could have a similar impact on the heart when they expose users to
similar amounts of nicotine, said Riccardo Polosa, director of the
Center for Smoking Prevention and Treatment at University of Catania
in Italy.
“Providing that the e-cigarettes deliver enough nicotine, the
physiological responses of the human body to vaping are no different
from those of smoking traditional cigarettes,” Polosa, who wasn’t
involved in the study, said by email.
However, it’s also possible that e-cigarettes may still be less
harmful than traditional cigarettes because they have lower
concentrations of cancer-causing chemicals, Polosa added.
“Moreover, patients who reduce or quit smoking by switching to
e-cigarettes may improve their cardiovascular, respiratory and
metabolic outcomes in the long term,” Polosa said. “Former smokers
using and smokers intending to use e-cigarettes should receive
correct information about the residual risks and potential benefits
of these products.”
SOURCE: http://bit.ly/2fARh63 Journal of the American Heart
Association, online September 20, 2017.
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