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What is smoking?

Smoking is an unhealthy behavior that can become an addiction. Smoking is the most important preventable cause of premature death in the United States, according to the American Heart Association.

Smoking includes all forms of smoking, such as cigar smoking, cigarette smoking, pipe smoking, and exposure to secondhand smoke. All forms of smoking are harmful and there is no form of safe or safer smoking. For example, smoking mentholated, natural, or low-tar, low-nicotine cigarettes does not lower the risk of serious complications of smoking.

Smoking causes or worsens many diseases and damages almost every tissue and organ in the body. Smoking causes the vast majority of cases of lung cancer and causes or exacerbates many other diseases, such as lung diseases, diabetes, cancer, and diseases and conditions of the cardiovascular system including hypertension, blood clots, high cholesterol, and stroke. Smoking also increases the risk of certain complications of pregnancy and sudden infant death syndrome (SIDS).

Smoking tobacco exposes you to over 4,000 chemicals, many of which are toxic. Toxins found in cigarettes include formaldehyde and cyanide. Another harmful substance in cigarettes and tobacco is nicotine. Nicotine is an addictive drug with serious side effects. Smoking also exposes you to carbon monoxide, which lowers the level of oxygen in the blood. People close to a smoker are exposed to the same toxins and can experience similar complications of smoking due to the inhalation of secondhand smoke.

Because of the addictive nature of smoking, quitting is a difficult challenge. However, quitting smoking is one of the best things you can do for yourself, your health, and your family and friends. Quitting smoking improves the health of the lungs and increases respiratory capacity. This is the ability to take in sufficient amounts of oxygen. People who quit smoking experience a rapid increase in oxygen levels in the blood, less shortness of breath with activities, feel less fatigue, and have more energy. Another important benefit of smoking cessation is the improvement in vital signs including a decrease in high blood pressure and pulse. The amount of carbon monoxide in the blood also drops after smoking cessation.

Because smoking constricts blood vessels and negatively affects circulation, smoking cessation is very beneficial for people who have other serious diseases that affect blood vessels and circulation, such as diabetes, congestive heart failure, and other cardiovascular diseases.


What are the symptoms of smoking and smoking-related diseases?

There are many signs and symptoms of smoking and smoking-related diseases including addiction to nicotine, a harmful substance found in tobacco.

Symptoms of smoking and smoking-related diseases

Symptoms of smoking and related diseases, disorders and conditions include:

  • Bad breath and yellowing of the teeth

  • Cold hands and feet

  • Frequent or recurrent lung infections and other diseases, such as influenza, common colds, bronchitis, and pneumonia

  • Hypertension (high blood pressure) and rapid heart rate

  • Loss of taste and smell

  • Low oxygen levels in the blood

  • Low tolerance for exercise and fatigue

  • Nicotine-stained fingers and teeth

  • Premature aging and wrinkling of the skin

  • Shortness of breath and difficulty breathing

  • Smoker's cough (an ongoing loose cough that produces phlegm) and hoarse voice

  • Smoky-smelling clothes and hair

Symptoms of smoking cessation

If you are a smoker who attempts to quit smoking, you may experience symptoms of nicotine withdrawal. Symptoms of nicotine withdrawal decrease over time and will eventually go away. Symptoms of nicotine addiction and nicotine withdrawal include:

Serious symptoms that might indicate a life-threatening condition

Long-term smoking can result in serious and life-threatening diseases and conditions, such as oral cancer, lung cancer, heart disease, chronic obstructive pulmonary disease (COPD), and pneumonia. Seek prompt medical care if you have sores or ulcers in your mouth that do not heal, which could be a symptom of oral cancer, or a cough that does not go away, which is a possible symptom of lung cancer.

Seek immediate medical care (call 911) if you, or someone you are with, have any of these potentially symptoms:


What causes smoking?

The Centers for Disease Control and Prevention estimates that 46 million people in the United States (18 years of age and older) smoke cigarettes. Smoking is more common in men than women and appears to be prevalent across a variety of different ethnic groups. The highest percentage of smokers is in the 25 to 44-year old age group.

Despite the prevalence of smoking, the factors that lead a person to start smoking are difficult to understand. In many cases, smoking is started at a young age due to peer pressure, tobacco advertising, or a concept that smoking is an acceptable behavior. Many people who start smoking have a family member or close friend who smokes.

Once started, cigarette smoking and chewing tobacco are difficult to stop. It is a well-known fact that smoking and chewing tobacco are behaviors that can become addictions due to the presence of nicotine and other chemicals generated from smoking. Like many other addictive substances, these chemicals trigger a series of biochemical reactions and pleasant sensations to which you can quickly become accustomed. Regular tobacco users eventually develop a need to experience these sensations in order to feel normal, which makes quitting a difficult challenge.

What are the risk factors for smoking?

Although there does not appear to be a specific trigger that causes a person to start smoking or chewing tobacco, there are several risk factors associated with smoking. Risk factors include:

  • Behavioral problems such as aggression

  • Family member who smokes

  • Lack of education past high school

  • Low self-esteem

  • Poor financial or social status

  • Poor school or academic performance


How is smoking treated?

Quitting smoking is a very challenging undertaking that often requires several attempts before you can successfully and permanently quit. If one method doesn't work, try another—the important thing is to just keep trying! Different people choose different strategies to quit. The best way to quit smoking is through a multifaceted smoking cessation program that includes perseverance, the support of the people close to the smoker, the use of new prescription medications that reduce the urge to smoke, and often nicotine replacement therapy.

Nicotine replacement therapy

Nicotine replacement therapy is one option that helps to minimize the nicotine cravings associated with nicotine withdrawal. Nicotine replacement therapy, when used as directed, is generally considered safe, and is safer than the nicotine in cigarettes. This is because nicotine replacement products contain lower amounts of nicotine than cigarettes and do not expose the smoker to the tar and toxic gasses contained in cigarette smoke.

Nicotine replacement therapies are available in a variety of forms including patches, gums and lozenges, which are available without a prescription. A nicotine replacement nasal spray, an inhaler, and nicotine pills are also available but require a prescription.

For optimal results when choosing and using a nicotine replacement therapy product, it is recommended that you see your health care provider prior to treatment. Because nicotine replacement therapies, like all medications, have potential side effects, a licensed health care provider will complete a full evaluation, including a medical history and physical, before recommending which product is best for you. Nicotine replacement therapy should not be used by pregnant or nursing women.

A supportive environment is also important for successful smoking cessation. This is because nicotine replacement therapy only helps smokers to withdraw from the physical symptoms of nicotine addiction, but does not help smokers to change the habitual behavior of smoking. If you are trying to quit smoking, a support group may help you to better cope with the psychological and physiological effects of no longer smoking.

What are the potential complications of smoking?

There are many complications of smoking that are serious and even life threatening. Smoking causes or aggravates many diseases and damages almost every tissue and organ in the body. Cigarette smoking was responsible for one in five deaths in the United States during 2000 to 2004, according to the Centers for Disease Control and Prevention.

People who are physically close to a smoker on a frequent basis can also experience similar effects due to the inhalation of secondhand smoke. Smoking cigarettes also exposes you to over 4,000 chemicals, many of which are toxic. Toxins found in cigarettes include formaldehyde and cyanide.

Smoking and cancer

Smoking causes many cancers and the vast majority of cases of lung cancer. Cancers caused by smoking include:

Smoking and lung, heart, and vascular disease

Smoking causes life-threatening lung and cardiovascular diseases, such as:

Smoking also exposes you to carbon monoxide, a gas that lowers the level of oxygen in the blood. This is further complicated by the fact that smoking constricts blood vessels, decreasing blood flow to vital organs, such as the brain and heart and large arteries of the arms and legs, which can lead to peripheral vascular disease. Smoking also thickens the blood and increases the risk of developing life-threatening blood clots and complications of blood clots including:

Smoking and pregnancy

Smoking causes or increases the risk of serious complications with pregnancy and infections in infants including:

  • Increased risk of ear infections in infants and toddlers exposed to secondhand smoke

  • Infertility

  • Low birth weight babies

  • Premature delivery

  • Stillbirth

  • Sudden infant death syndrome (SIDS)

Other complications of smoking

Smoking worsens or increases the risk of many diseases and serious medical conditions including:

Smoking also exposes you to nicotine, which is an addictive drug whose side effects include:

  • Increased heart rate

  • Blood vessel irritation and a higher risk of developing blood clots, which increases the risk of cardiovascular disease, heart attack, and stroke

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2018 Dec 27
    1. Smoking & Tobacco Use. Fast Facts and Fact Sheets. Centers for Disease Control and Prevention.
    2. U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress. A Report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014.
    3. Quit Smoking / Tobacco / Vaping. American Heart Association.
    4. Smoking. Medline Plus, a service of the National Library of Medicine National Institutes of Health. https://medlineplus/smoking.html
    5. Tobacco and Cancer. American Cancer Society.

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