The stimulation from the nicotine is mainly what you’re feeling. Try drinking some strong caffeinated soda or coffee quickly and you’ll feel something similar although, since you’re likely more accustomed to that drug it won’t feel as strong, and since you’re absorbing it through your digestive system more slowly it won’t be as notable.
One or two folks have mentioned hypoxia. If you’re smoking a dozen cigarettes in a half hour or hour, then I could see hypoxia being a problem. Since you state you’re not used to smoking, then I doubt you’re smoking that many. If smoking a single cigarette or two could actually cause hypoxia to such an extent then chain smokers would quickly die from lack of oxygen and you’d constantly have to be stepping over their bodies in the streets.
Nicotine is not an opiate like morphine etc. It’s much closer to being like caffeine.
MJM, not that big on caffeine… love my nicotine and chocolate though!
This answer originally appeared on this Quora question on Vertigo Dizzy.