Haven't been to a doc in a long time... but if asked I'd just say: "It's none of your business!" I'm a little bit like that...

Probably the only way I'll see a doc is if someone hauls me off to an ER .... and against my will!
That's certainly your prerogative,but coming from a
30 year...almost 3 pack a day smoker ...
(who HAS been dragged to the er against his will ,where they admitted me and placed two stents in my chest)
I can share what I've learned about nicotine.
Nicotine affects the entire body. It acts directly on the heart to change heart rate and blood pressure. It also acts on the nerves that control respiration to change breathing patterns. In high concentrations, nicotine is
deadly, in fact
one drop of purified nicotine on the tongue will kill a person! It's so lethal that it has been used as a pesticide for centuries.
So why do people smoke? Because nicotine acts in the brain where
it can stimulate feelings of pleasure and reward.
The nicotine molecule is shaped like a neurotransmitter called acetylcholine. Acetylcholine and its receptors are involved in many functions, including
muscle movement, breathing, heart rate, learning, and memory. They also cause the release of other neurotransmitters and hormones that affect your mood, appetite, memory, and more. When nicotine gets into the brain, it attaches to acetylcholine receptors and mimics the actions of acetylcholine.
Recently, scientists discovered that nicotine raises the levels of a neurotransmitter called dopamine in the parts of the brain that produce feelings of pleasure and reward. Dopamine, which is sometimes called the pleasure molecule, is the same neurotransmitter that is involved in addictions to other drugs such as ....... and ....... Researchers now believe that this change in dopamine may play a key role in all addictions. This may help explain why it is so hard for people to stop smoking.
By the way,
Less than six months after my heart procedure I was back to 3 packs a day and have been for 9 years since.
I've tried the patches,gum,inhalers,pills and cold turkey.
I've pretty much givin up on the heart now haha.
Now I'm going to try "vaping"
to at least stop doing damage to my lungs as well.