TedEd-16

How Do Cigarettes Affect
the Body?

Cigarettes aren’t good for us. That’s hardly news--we’ve known about the dangers of smoking fordecades. But how exactly do cigarettes harm us? Let’s look at what happens as their ingredientsmake their way through our bodies, and how we benefit physically when we finally give up smoking.
With each inhalation, smoke brings its more than 5,000 chemical substances into contact with thebody’s tissues. From the start, tar, a black, resinous material, begins to coat the teeth and gums,
damaging tooth enamel, and eventually causing decay. Over time, smoke also damages nerveendings in the nose, causing loss of smell. Inside the airways and lungs, smoke increases thelikelihood of infections, as well as chronic diseases like bronchitis and emphysema. It does this bydamaging the cilia, tiny hairlike structures whose job it is to keep the airways clean. It then fills thealveoli, tiny air sacs that enable the exchange of oxygen and carbon dioxide between the lungs andblood. A toxic gas called carbon monoxide crosses that membrane into the blood,binding tohemoglobin and displacing the oxygen it would usually have transported around the body. That’s

TedEd-16

How Do Cigarettes Affectthe Body?

one of the reasons smoking can lead to oxygen deprivation and shortness of breath. Within about
10 seconds, the bloodstream carries a stimulant called nicotine to the brain, triggering the release of
dopamine and other neurotransmitters including endorphins that create the pleasurable sensations
which make smoking highly addictive. Nicotine and other chemicals from the cigarette
simultaneously cause constriction of blood vessels and damage their delicate endothelial lining,restricting blood flow. These vascular effects lead to thickening of blood vessel walls and enhanceblood platelet stickiness, increasing the likelihood that clots will form and trigger heart attacks andstrokes.
Many of the chemicals inside cigarettes can trigger dangerous mutations in the body’s DNA thatmake cancers form. Additionally, ingredients like arsenic and nickel may disrupt the process of DNA
repair, thus compromising the body’s ability to fight many cancers. In fact, about one of every threecancer deaths in the United States is caused by smoking. And it’s not just lung cancer. Smoking cancause cancer in multiple tissues and organs, as well as damaged eyesight and weakened bones. It
makes it harder for women to get pregnant. And in men, it can cause erectile dysfunction. But for
those who quit smoking, there’s a huge positive upside with almost immediate and long-lasting
physical benefits. Just 20 minutes after a smoker’s final cigarette, their heart rate and bloodpressure begin to return to normal. After 12 hours, carbon monoxide levels stabilize, increasing theblood’s oxygen-carrying capacity. A day after ceasing, heart attack risk begins to decrease as bloodpressure and heart rates normalize. After two days, the nerve endings responsible for smell andtaste start to recover. Lungs become healthier after about one month, with less coughing andshortness of breath. The delicate hair-like cilia in the airways and lungs start recovering withinweeks, and are restored after 9 months, improving resistance to infection. By the one-year
anniversary of quitting, heart disease risk plummets to half as blood vessel function improves. Fiveyears in, the chance of a clot forming dramatically declines, and the risk of stroke continues toTedEd-16

How Do Cigarettes Affectthe Body?

reduce. After ten years, the chances of developing fatal lung cancer go down by 50%, probably
because the body’s ability to repair DNA is once again restored. Fifteen years in, the likelihood ofdeveloping coronary heart disease is essentially the same as that of a non-smoker.
There’s no point pretending this is all easy to achieve. Quitting can lead to anxiety and depression,resulting from nicotine withdrawal. But fortunately, such effects are usually temporary. And quitting
is getting easier, thanks to a growing arsenal of tools. Nicotine replacement therapy through gum,skin patches, lozenges, and sprays may help wean smokers off cigarettes. They work by stimulating
nicotine receptors in the brain and thus preventing withdrawal symptoms, without the addition ofother harmful chemicals. Counselling and support groups, cognitive behavioral therapy, andmoderate intensity exercise also help smokers stay cigarette-free.
That’s good news, since quitting puts you and your body on the path back to health.