What are smoking's effects on the body?

Quick Answer
Tobacco smoking leads to bodily changes such as increased blood pressure and heart rate within minutes or hours of inhalation. Habitual smoking has long-term consequences such as chronic lung and coronary heart disease and numerous cancers.
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Short-term Effects

A major reason for the spread and popularity of tobacco since the sixteenth century is connected to one of its short-term effects on the human body. An important active ingredient in tobacco smoke is nicotine, which is rapidly delivered into the bloodstream through the lungs. Nicotine is then transported to receptors in the central nervous system, increasing heart rate and the release of dopamine, a pleasure-inducing chemical. Tobacco smoke also contains chemical substances that increase heart rate and elevate blood pressure, sometimes causing dizziness and tremors because of a reduced flow of oxygenated blood to the brain and extremities.

Smoking also has short-term effects on the respiratory and digestive systems. Research on animals and humans has demonstrated that inhaling smoke from cigarettes impairs pulmonary clearance, which can lead to coughing and increased susceptibility to colds and allergens. Smoking attenuates the functioning of the lung’s cilia and alveoli, reducing the lung’s ability to oxygenate blood.

With regard to the digestive system, studies indicate that components of cigarette smoke foster increased acidity in the stomach, while other studies show that smoking may exacerbate gastric and duodenal ulcers. Deceptive advertisers have at times created the impression that one of the beneficial aspects of smoking is appetite reduction, instilling the fear that cessation of smoking will lead to weight gain. Many researchers, however, insist this fear must be directly opposed because documented weight gain after cessation has complex causes.

The body’s nervous, muscular, and reproductive systems are quickly affected by certain components in tobacco smoke. Because nicotine readily passes through the blood-brain barrier, it stimulates certain receptors that in novice smokers may induce nausea. In experienced smokers, however, this fact may explain why, with various physiological changes, some of them pleasurable, smoking becomes a deeply entrenched habit. Much research indicates that nicotine plays a significant role in establishing the smoking habit, though some smokers become dependent on nicotine-free cigarettes.

Because of smoking’s negative effects on the muscular system, athletes have been perennially warned about smoking’s ability to impair performance. Also, extensive research has been done on the immediate effects of smoking during pregnancy and the multiple harmful chemicals in cigarette smoke on the fetuses of animals and humans. These chemicals cause such effects as changes in fetal heart rate and placental circulation and metabolism; a rise in carboxyhemoglobin concentrations; and a host of other problems, which have led to a series of warnings that pregnant women should not smoke.

Long-Term Effects

Scientific research has revealed that smokers are exchanging short-term pleasures for a devastating array of extremely negative long-term health consequences, including chronic problems for the circulatory, respiratory, and other bodily systems. Extensive research has shown habitual smoking dramatically increases the risk for arteriosclerosis and coronary heart disease. General agreement exists that acute and chronic cardiovascular effects of smoking can be largely attributed to nicotine. Smoking also has been associated with narrowing of the blood vessels in the heart, brain, and other organs, significantly increasing the chances of stroke.

According to some analysts, the body’s respiratory system experiences the most devastating damage from long-term smoking. Evidence shows a causal relationship between smoking and lung cancer, and that smokers are more than ten times as likely as nonsmokers to have lung cancer. These studies also indicate that more than 90 percent of all lung-cancer cases in men, and 80 percent in women, are caused by smoking. Furthermore, habitual smoking has been associated with increased susceptibility to such chronic obstructive pulmonary diseases as emphysema and bronchitis. According to the US Centers for Disease Control and Prevention, men who smoke increase their risk of dying from bronchitis and emphysema by seventeen times.

Because smoking reduces the effectiveness of the body’s immune system, habitual smokers readily have a variety of respiratory infections, including pneumonia. Other research has established a causal relationship between smoking and cancers of the digestive and urinary systems. For example, smokers are much more likely to develop and die from mouth and throat cancers, stomach cancers, colorectal cancer, pancreatic cancers, bladder cancer, and kidney cancer. Indeed, several analysts believe that 30 to 50 percent of all cancer deaths in the United States can be directly attributed to smoking. Worldwide, tobacco use causes nearly six million deaths each year. Smokers die an average of ten years earlier than nonsmokers.

Much research has been devoted to studying the long-term health effects of smoking on the reproductive system. These studies have revealed negative effects from fertilization to birth. Smoking causes lowered fertility; stunted fetal growth; increased likelihood of miscarriages, premature births, and stillbirths; and complications for normal-term births. Women who are habitual smokers also give birth to babies with low birth weights, and the harmful chemicals in the bodies of breastfeeding mothers who are smoking can be passed to their babies, causing immediate and long-term damage. The reproductive systems of men also are affected by smoking, with reduced sperm count and increased impotency the most commonly reported problems.

Although the negative cosmetic effects of smoking are not as serious as the effects on the major systems of the body, they have, nevertheless, been studied. For example, smoking leads to premature aging of the skin, chiefly by interfering with the collagen production involved in renewing skin. Habitual smoking often results in bad breath, stained teeth, discolored fingers, and an unhealthy complexion.

Because of all the short- and long-term effects of smoking on the body, various institutions, including the World Health Organization, the US Office of the Surgeon General, and the American Heart Association, have persistently urged smokers to quit so that they might enjoy longer, healthier lives.


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Siegel, Rebecca L., et al. "Deaths Due to Cigarette Smoking for 12 Smoking-Related Cancers in the United States." JAMA Internal Medicine 175.9 (2015): 1574–76. Print.

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