Tobacco is one of the most powerful stimulants known to man. A single puff of a cigarette exposes the body to over 4,000 chemical compounds and 600 additives.
The effects of nicotine when it enters the bloodstream via the lungs are almost immediate. Nicotine reaches the brain within 10 seconds and stimulates the secretion of adrenaline, which boosts your heart rate and increases blood pressure. Once in your bloodstream, nicotine flows immediately to your brain.
More than 90% of the nicotine inhaled is absorbed by the lungs. Nicotine enters the body in the form of thousands of little droplets, each suspended in a solid particle of tar. These nicotine droplets are so small that they can penetrate into the tiniest avenues of the lungs. Once in the lungs they are picked up by blood, which has been sent to the lungs to take up oxygen for circulation in the body. From the lungs, it moves quickly to the left side of the heart, where nicotine is pumped out to the body.
Brain scans of smokers where compared to non-smokers show how nicotine changes the structure of the brain by mimicking the effects of Acetylcholiine (ACH), one of the body's most important neurotransmitters. ACH is very important in the structure of the body's autonomic nervous system, which controls bodily functions.
When the body gets a nicotine hit, the heart rate will increase by 10 to 20 beats per minute. Blood pressure will increase by 5 to 10 points. Nicotine makes the heart work harder. Harmful gases in the smoke cause the blood vessels to narrow, giving greater risk of heart disease and stroke. Carbon monoxide passes through the lungs and into the blood, restricting the oxygen flow to the body, thickening the blood. It is this lack of oxygen that causes the smoker to feel tired.
As the stimulant (nicotine) enters the body, it releases adrenaline from the brain. This adrenaline puts the body on “alert” and the primal “fight or flight” response is triggered, putting the body falsely on danger alert. This response causes the body to deposit some of its glucose stores into your blood, for more energy to “fight or flight”. The body, by now, is in the process of heightened alertness and unnecessary and unnatural stress.
Nicotine in the blood also blocks the release of the hormone insulin. Insulin instructs your cells to take up excess glucose from your blood. This blocking of the release of insulin can make smokers somewhat hyperglycemic, having more sugar in their blood than is usual.