human
I've heard a lot about the dangers of e-cigarettes. Is there any evidence that they are harmful?
assistant
There is some evidence that e-cigarettes can cause respiratory irritation and increase heart rate, but it’s not clear whether these effects are caused by nicotine or other chemicals in the vapor. The long-term health effects of vaping are unknown. It’s important to follow safety guidelines when using e-cigarettes, such as never inhaling directly from the device, avoiding high temperatures, and keeping the device away from children.