I can only speak from my own experience and knowledge I have gathered from vaping and discussions between myself and my primary care physician.
1) Nicotine does temporarily constrict blood flow for a time immediately after inhalation, no getting around it, but the effects with vaping are far less than with a cigarette as the nicotine concentration is lower than with a full blown cigarette (I chain vape on 12mg for most of the day when I am idle, compared to chain smoking cigarettes when idle which have after combustion about 48 to 52mg exposure). To swear off nicotine entirely means cutting out a major portion of your vegetable intake like tomatoes, egg plant, any of the "Night Shade" family which tobacco is part of, all of the Night Shade family produce nicotine in various levels. Yet the anti-smoke/anti-vape zealots try to disregard this little fact of life, they look at us as sinners, I point the finger right back, like tomatoes you are a sinner as well, get off my lawn and go home now...
2) Nicotine constriction of the blood flow is amplified and compounded by other toxins in cigarette smoke, only 4 toxins I vape in if you can call them that, nicotine, PG, and VG, maybe a slight menthol or tobacco flavoring to my juice. Hmm, cigarette is 4000+ chemicals and toxins, yeah, I'll take my chances with vaping as my harm effect vectors are drastically reduced with vaping. Again get off my lawn, go home and quit barking up my tree before I drop a stone on your head for violating my personal space with your preaching.
3) This is minor, but also a major factor, nicotine is proving to be beneficial in fighting dimensia, alzheimer's and several other neurological diseases, I'll take my risks with keeping nic in my body chemistry to fight it as long as I can given both sides of my family have history of elder dimensia.
