Smoking e-cigarettes with nicotine may cause arteries to stiffen and increase the risk of heart attacks and strokes later in life, a study warns.
Researchers, including those from Karolinska Institute in Sweden, found that there was a significant increase in heart rate and blood pressure in the volunteers who were exposed to e-cigarettes containing nicotine.
Arterial stiffness increased around three-fold in those who were exposed to nicotine containing e-cigarettes compared to the nicotine-free group, researchers said.
In the first 30 minutes after smoking e-cigarettes containing nicotine, researchers noted that there was a significant increase in blood pressure, heart rate and arterial stiffness.
No such effect was seen on heart rate and arterial stiffness in the volunteers who had smoked e-cigarettes without nicotine, they said.
"The immediate increase in arterial stiffness that we saw is most likely attributed to nicotine," said Magnus Lundback from Karolinska Institute.
Chronic exposure to both active and passive cigarette smoking causes a permanent increase in arterial stiffness.
Therefore, we speculate that chronic exposure to e-cigarettes with nicotine may cause permanent effects on arterial stiffness in the long term, researchers said.
Researchers recruited 15 young, healthy volunteers to take part in the study in 2016. The volunteers were seldom smokers (smoking a maximum of ten cigarettes a month), and they had not used e-cigarettes before the study.
The average age of the volunteers was 26 years. They were randomised to use e-cigarettes with nicotine for 30 minutes on one of the study days and e-cigarettes without nicotine on the other day.
The researchers measured blood pressure, heart rate and arterial stiffness immediately after smoking the e-cigarettes and then two and four hours later.