We all know the truth about smoking. It kills people. Did you know that nearly 1 in 5 deaths are related to cigarette smoke? And yet studies show that still at least 21% of Americans continue to smoke. Why is that?
One word: Nicotine. Out of the 4,000 chemicals in tobacco, it's the main drug that acts on the brain.
When inhaling tobacco smoke, the average smoker takes in 1 to 2 mg of nicotine per cigarette. When tobacco is smoked, nicotine rapidly reaches peak levels in the bloodstream and enters the brain. A typical smoker will take 10 puffs on a cigarette over a period of 5 minutes that the cigarette is lit. Thus, a person who smokes about 1-1/2 packs (30 cigarettes) daily gets 300 "hits" of nicotine to the brain each day.
People that typically do not inhale the smoke-such as cigar and pipe smokers and smokeless tobacco users--nicotine is absorbed through the mucosal membranes and reaches peak blood levels and the brain slowly.
Immediately after exposure to nicotine, there is a rush of adrenaline, caused in part by the drug's stimulation of the adrenal glands and resulting discharge of epinephrine. The rush of adrenaline stimulates the body and causes a sudden release of glucose, as well as an increase in blood pressure, respiration, and heart rate. Nicotine also suppresses insulin output from the pancreas, which means that smokers have elevated blood sugar levels. The calming effect of nicotine for most smokers is usually associated with a decline in the withdrawal from nicotine, rather than direct effects of nicotine.
You see, nicotine activates the part of the brain that regulates feelings of pleasure. Cigarette smoking produces a rapid distribution of nicotine to the brain, with drug levels peaking within 10 seconds of inhalation. But, the intense effects of nicotine subsides in a few minutes, as do the associated feelings of pleasure, which causes the smoker to continue smoking more and more to maintain the drug's pleasurable effects and prevent withdrawal.
Nicotine withdrawal symptoms include irritability, craving, cognitive and attention deficits, sleep disturbances, and increased appetite. These symptoms may begin within a few hours after the last cigarette, quickly driving people back to tobacco use.