Vaping may be as bad for the heart as smoking, a review says. Experts say there is “more and more reason to worry” about e-cigs, The Sun reports.

They may even be harmful for bystanders exposed to second-hand vapour, it is claimed.

Researchers from Ohio State University in the US analysed previous studies on vaping.

The team found, like with smoking, it increases blood pressure, heart rate, stiffness of the arteries and inflammation. All are linked to heart disease.

UK health chiefs say it is 95 per cent safer than tobacco. But in addition to nicotine, e-cigs can contain tiny particles, metals and flavouring, which may fuel problems.

Study leader Prof Loren Wold said: “There is more and more reason to worry.

“The potential harm to the heart over time is essentially unstudied.”