Smokers can improve the health of their hearts within weeks of switching to e-cigarettes, the largest trial of its kind shows.
The month-long study of 114 smokers suggests vaping has the potential to reduce heart attack and stroke risk.
The British Heart Foundation said stopping smoking was the single best thing you could do for your heart.
Chemical substances in cigarette smoke slim arteries since they get furred with greasy deposits increasing the risk of a fatal blockage. Ultimately smoking cigarettes doubles your risk of using a heart attack.
But the researchers mentioned the present evidence on vaping was "poor" and quite often examined the impact of any individual e-cigarette on cardiovascular system wellness.
So that they supervised people's bloodstream a month when they had been switched to e-cigs in the test.
They focused on how blood vessels increase whenever a wave of bloodstream rushes through, by calculating "stream-mediated dilation".
The more the bloodstream are able to broaden the much healthier they may be. Stream-mediate dilation ratings have already been closely linked to the long-term probability of heart attacks and stroke.
The results, published in the Journal of the American College of Cardiology, showed:
- Healthy non-smokers had a score of 7.7percent
- Smokers had a score of 5.5percent
- But those who switched to nicotine e-cigarettes for a month had a score of 6.7percent
So, switching to vaping got those smokers about halfway back to a healthy score.
"They're not quite normal, but their vascular function improved quite significantly, just within a month," said one of the researchers, Professor Jacob George.
Prof John Britton, director of the UK centre for tobacco and alcohol studies at the University of Nottingham, said: "This randomised trial provides clear evidence of a reduction in a marker of cardiovascular disease risk in people who switch from smoking to vaping.
"The finding of the study, that vaping is less harmful than smoking,