Okay, I am not a doctor, but I have done research on this. The physical addiction to cigarettes is gone within 72 hours.....but the psychological addiction is what hangs on and makes it difficult for people to quit. Your body and mind are trained to believe that smoking helps you relax. They are trained to want a cigarette while driving, or after eating, or when you are drinking at a bar.
The key to breaking the addiction is breaking the habit. When you feel a craving for a cigarette, make a conscious decision to focus on something else, like deep breathing. Try yoga breathing.....breathe in for 4 slow counts and out for 4 deep counts. Repeat over and over while trying to clear your mind. If you can make it for 5 minutes (you don't have to deep breathe the whole time, but hang on and don't give in), the craving will pass. Meanwhile, you are creating a new habit to replace the old one.
Smoking constricts blood vessels, which actually decreases oxygen to your brain. Deep breathing increases oxygen flow to your brain, which will make you think more clearly and calmly than ever.
Also, find a really good gum to occupy your mouth. I really love Orbit Bubblemint Gum....it is honestly the best gum I have ever had, and I have turned about 20 people onto it now.
So, deep-breathing and gum. I know it sounds silly, but the deep-breathing is very important and very, very, very useful. I use it now to center myself during tense matches...and I am having great success with it. At the last Pro event in Peoria, I used it in every match, and I finished 5th. When I found myself getting nervous or tense, I would just take several deep breaths while my opponent was at the table and then I would feel clear-headed and calm when it was my turn.
Hope this helps! And I feel doubly committed now that I have reviewed this info myself and shared it with you! Best of luck in all you do!
Melissa