I am not a doctor, Jim, but I believe carbon monoxide is the component of cigarette smoke responsible for causing poor circulation. CO (carbon Monoxide) is a byproduct of combustion, so it is not present in vapor. On a more empirical and personal note, I have been
vaping heavily for almost a year, and my circulation is better than it ever was as a smoker. In fact, living in Utah, I find that warm fingers and toes is one of the best positive effects of switching from analogs.