Vaping has an immediate effect on how well the user’s blood vessels work, even if the e-cigarette doesn’t contain nicotine, according to new research.

The research – which has not been published in a peer-reviewed journal but is a presentation at the annual meeting of the Radiological Society of North America in Chicago – showed that using an e-cigarette with or without nicotine also decreased a metric known as venous oxygen saturation, which may mean the person’s lungs were taking in less oxygen.a