combustible cigarettes FDA drafts guidance to help e-cigarettes apply under novel drug status From the Chief Medical Officer:

Third, available research lacks the independence and quality that might help us draw any conclusions about the impacts of real-world use, Braznell told a media briefing on Wednesday

Chemical hazards present in liquids and vapors of electronic cigarettes

Of course, the easiest way to avoid this problem is to quit smoking or have smokers go outside

DO NOT Exercise Directly Before or After Smoking This will raise your blood pressure more than the nicotine alone and can make the effects of nicotine come on sooner and harsher

Ryan Hibbs and colleagues in Breakthrough in Mapping Nicotine Addiction Could Help Researchers Improve Treatment, reveals the receptors 3D structure, shedding light on how nicotine interacts with the brain