The Effects of Smoking

Most smokers are aware that smoking dramatically increases the risk of developing lung cancer. But habitual smokers may not realize smoking’s other harmful effects. Each enticing puff of smoke contains a toxic stew of compounds; up to 250 harmful chemicals, including nearly 70 that are known to cause cancer. These poisons range from nervous system toxins—like the heavy metals, arsenic and cadmium—to known carcinogens, such as formaldehyde and benzene. Arsenic is a classic poison familiar to fans of murder mystery fiction, while formaldehyde is used in embalming fluid—to preserve dead bodies. 

With each puff, smokers draw smoke into the mouth, sinuses, and throat. Smoke travels past the voice box, down the windpipe, through the bronchial tubes, and into the tiny air sacs (alveoli) deep in the lungs. From there, toxic smoke chemicals pass into the bloodstream. Chemicals are quickly distributed to tissues throughout the body, and within 10 seconds chemicals reach the brain. Highly addictive nicotine binds with brain receptors, triggering changes that affect mood, behavior, and maybe even intelligence. 

Among other effects, cigarette smoke irritates the tissues that line the trachea and bronchioles of the lungs. This tissue, known as the respiratory mucosa, secretes excess mucus in response to irritation. Tar from cigarettes gets trapped in this thick, sticky mucus, and the mix slows the activity of cilia: hair-like projections lining the airways, which function to help move foreign objects out of the airways. As the cilia struggle to remove excess mucus, the classic smoker’s cough develops. It’s part of the body’s desperate effort to remove excess mucus and the toxic chemicals trapped in it.

Smoking gradually damages the delicate tissues of the respiratory tract and lungs. Initially pink and healthy, here we see the tiny air sacs (alveoli) where life-giving oxygen enters the bloodstream and carbon dioxide is eliminated. Tobacco smoke leaves behind a toxic, black sticky residue known as tar. Over time tar builds up, damaging the alveoli. As the damage progresses, breathing becomes more difficult. The lungs literally change from healthy pink to ugly black. Tar contains a known cancer-causing substance. Eventually, cancerous tumors may grow deep in the lungs. 

Smoking reduces the amount of oxygen that reaches the body’s cells. It also causes the blood vessels to contract. This leads to constricted blood flow—especially in tiny capillaries—and increased blood pressure. The risk of cardiovascular disease increases as the linings of blood vessels become inflamed and damaged by atherosclerosis. Over time, blood vessel damage, especially in the extremities, may become irreversible. Long-term smokers are more prone to peripheral arterial disease and other circulation problems, including increased risk of gangrene, impotence, and limb amputation.  

Smoking damages the cardiovascular system, including the heart. The heart compensates for blood vessel constriction and falling oxygen levels induced by smoking by growing larger. This enlargement (cardiac hypertrophy) signals serious, progressive heart disease, which may lead to fatal congestive heart failure. Ultimately, heart muscle cells may die from poor blood flow. Oxidative stress and inflammation, among other processes, are caused by toxins in cigarette smoke. These processes are believed to underlie many of the negative changes in the cardiovascular system.

Smoking affects every organ in the body, including the eyes. For example, the risk of developing a condition called macular degeneration is two to three times greater among smokers. In this animation, we see the progressive damage done to the area of the retina (the macula) where the bulk of detailed vision occurs. People with advanced macular degeneration may lose significant visual acuity. The inset video image of children playing illustrates how a person’s vision changes as macular degeneration progresses. Smoking is also associated with an increased risk of cataracts. 

If looking older is your goal, keep smoking. But be careful what you wish for. Smoking damages the body from the inside out, but its effects may be most obvious on the skin of the face. Smokers suffer premature skin aging, and the damage is irreversible. Signs of advanced skin aging include crow’s feet around the eyes, excessive wrinkling, bags under the eyes and sagging skin. According to some experts, the skin of a long-term smoker at 40 may resemble the skin of a non-smoker at 70.

Now that you know what smoking does to your body, the next step is finding a smoking cessation program that works for you. Make a concentrated effort to kick the habit, and fight the cravings to relapse. By doing so, you'll add years to your life.