The researchers found that after five minutes of exposure, the short-term group's arteries were 30% narrower, and vasodilation (widening of the vessels when needed) was impaired too. This affects the ability of the circulatory system to provide oxygen and nutrients to tissues, as well as to remove toxins. It also puts increased pressure on the cardiovascular system and therefore increases the risk of damage. As for the long-term group, 20 hours of exposure per week over 8 months doubled aortic stiffness compared to only breathing normal room air.
What is wrong with e-cigarettes? Other research has shown that they can produce dangerous levels of carcinogens such as formaldehyde. The level of this and other toxic aldehydes was dependent on the amount of flavouring, which decomposed into these chemicals when it was heated up. This is what the vapour is made of. But in all concentrations and all flavours, the level of toxic aldehydes produced was higher than the limit for chemical exposure set by the American Conference of Governmental Industrial Hygienists. There are thousands of flavours on the market where e-cigarettes are sold, and they may be attractive to younger people and other non-smokers, so there is a risk of harm instead of them being a quitting aid. While yet another study found that e-cigarettes were 95% less dangerous than smoking, it is clear that they are not harmless. They may be a useful short-term aid in quitting smoking, but should not be used forever.