Why is smoking harmful? Here's why you should quit

With every cigarette you smoke, several thousand chemical compounds enter your body. A large proportion of them are carcinogenic, damage your blood vessels, or harm your health in other ways. What exactly happens to your lungs, your heart, and your blood vessels when you smoke? What do 20 or 40 years of smoking actually mean for your life expectancy? And from when does the risk of cancer increase? In this article, you’ll find answers to these and other questions.

Smoking damages your lungs, heart, blood vessels, larynx, bladder, and other organs.

What’s in cigarette smoke? Toxins and groups of harmful substances

It’s no secret that tobacco smoke is toxic. But what exactly makes it so harmful? When tobacco is burned, more than 7,000 chemical substances are produced, around 250 of which have a harmful effect on your body. More than 90 of these substances are carcinogenic or potentially carcinogenic, including cadmium, lead, and formaldehyde.⁹

On top of that, the substances contained in smoke amplify each other’s harmful effects. There is no threshold below which cigarette smoke is not harmful to health. The smoke inhaled by passive smokers also contains the same substances as the smoke inhaled by active smokers. In addition, tobacco smoke doesn’t “just” damage nearly all organs, it also affects mental health.²

The four groups of harmful substances

The harmful ingredients in tobacco smoke are divided into the following four groups of harmful substances:

• Irritating substances irritate your eyes, mucous membranes, airways³ and skin.¹ Examples of substances in this group found in tobacco smoke include formaldehyde, benzene, and acrylonitrile.¹
• Blood-toxic substances damage peripheral blood vessels, meaning blood vessels outside the central area of the heart and chest. This leads to reduced blood flow to your organs, which is why these substances are also one of the main causes of cardiovascular disease. The best-known blood-toxic substance in cigarette smoke is carbon monoxide (CO). CO binds to hemoglobin (the red pigment in red blood cells whose job is to carry oxygen from the lungs to the rest of the body) and thus impairs the transport of oxygen to your organs.³
• Narcotic substances have a numbing effect. This group also includes nicotine, which has a calming effect and can increase alertness and concentration. However, it is also the ingredient responsible for strong dependence. Nicotine is not, however, the main cause of smoking-related diseases.³
• Carcinogenic substances there are at least 70 substances in cigarette smoke. They damage the DNA in your cells and thereby promote the development of cancer.³ Examples of carcinogenic substances in tobacco smoke include benzene, cadmium,¹ nitrosamines, and polonium-210 (a radioactive element). If you smoke 20 to 40 cigarettes a day for a year, this is also comparable to the exposure from around 250 chest X-rays.⁵

Tar, nicotine and carbon monoxide — the three best-known harmful substances

Tar is a sticky mixture of toxic chemicals produced when tobacco is burned. This substance settles in your airways and lung tissue. Tar is highly carcinogenic and clogs the cilia in the bronchi, which normally transport dirt and mucus away. Your body then tries to get rid of this mucus by coughing instead — this is what’s known as smoker’s cough.⁴ By the way, tar doesn’t just leave traces inside the body, but on the outside too: it’s the reason for yellow fingers and teeth from smoking.

Nicotine is a natural neurotoxin found in the tobacco plant and is mainly responsible for the physical and psychological dependence (nicotine addiction) caused by cigarettes. The substance binds to receptors in the brain’s reward center, creating a positive feeling. You can find detailed information on this in the article about the effects of nicotine.

However, tolerance develops quickly, requiring ever higher doses. Nicotine is not responsible for cancer or most vascular damage,³ but it does increase blood pressure and heart rate and constricts blood vessels, which raises strain on the heart in the short term. How much nicotine a cigarette contains depends heavily on the brand and how you smoke it.

Carbon monoxide (CO) is a colorless, tasteless, and odorless respiratory poison. It binds to hemoglobin around 200 times more strongly than oxygen,⁵ reducing the body’s oxygen supply, which damages organs and blood vessels. Your heart beats faster to maintain the oxygen supply, which also leads to high blood pressure.

Smoking and cardiovascular health: blood pressure, heart attack, stroke

Smoking increases blood pressure and is one of the main risk factors for cardiovascular disease. Smoking also promotes the formation of blood clots, making your blood thicker and more likely to clot quickly, which can lead to a blocked blood vessel. Cigarette smoke damages blood vessels, which promotes calcification of the vessels and eventually arteriosclerosis (hardening of the arteries). Smoking also impairs blood flow in the arms and legs, and it can lead to a heart attack or, due to narrowed blood vessels in the head, a stroke.

Here are a few figures that illustrate the cardiovascular risk caused by smoking:

• The risk of heart attack for smokers is twice as high as it is for non-smokers.⁷
• Even one cigarette a day is enough to increase cardiovascular risk.⁷
• According to the World Health Organization (WHO), smoking-related cardiovascular disease is responsible for one in five deaths (21%).⁶

How can you reduce your cardiovascular risk? The best way to counter these health risks is to quit smoking, even after many years of smoking. After just one smoke-free year, the risk of heart attack is cut in half, and the risk of stroke after 5 years.⁶

Tips & home remedies to quit smoking

COPD and smoking: life expectancy and disease progression

COPD and smoking are inseparably linked: Tobacco smoke is the most common cause of chronic obstructive pulmonary disease (COPD), a permanent narrowing of the airways.⁹ The more you smoke and the longer you smoke, the further COPD progresses. The narrowing of the airways restricts the body’s oxygen supply. In advanced stages of the disease, breathing becomes difficult even at rest. COPD causes increasing destruction of lung tissue and permanently irritates the bronchi.

What COPD does to your life

The average life expectancy in Germany is 80 years. COPD reduces this figure by 5–7 years, and if you continue smoking despite the disease, it can even be reduced by up to 9 years.¹⁰ Exact life expectancy depends on several factors such as forced expiratory volume in one second (FEV1), nicotine consumption, possible worsening of the disease (exacerbation), age, and comorbidities. As the severity of COPD increases, heart rate also rises, which further increases mortality. Avoiding smoking can significantly extend life expectancy.¹¹

What the FEV1 value indicates

So how can you actually measure how much the lungs have already changed due to COPD? In medicine, this is assessed using what is known as forced expiratory volume in one second (FEV1). This is the volume of air that you can forcefully exhale within one second after taking a deep breath. The lower your lung function is, meaning the less volume you exhale, the more advanced the stage of COPD and the shorter the life expectancy. Smoking accelerates the decline in FEV1 much more rapidly than normal aging alone.

Quitting smoking changes the prognosis

While quitting smoking cannot reverse the course of COPD, it can help contain it. The decision to stop smoking immediately is considered the most important measure for stopping, or at least slowing down, the progression of lung damage caused by COPD. Smoking cessation also reduces coughing and shortness of breath.

How long do you have to smoke before cancer develops? Timeline and risks

At what age does smoking significantly increase the risk of developing cancer? There is no fixed period after which smokers get cancer. An individual’s cancer risk depends on Quantity, duration, the type of tobacco consumed, and genetic predisposition. On average, lung cancer develops 30 to 40 years after starting to smoke regularly.¹² If you start smoking at a young age, your risk of developing cancer is even higher than for smokers who start later.¹² In general, cancer risk increases with what are known as pack years. Pack years indicate how many cigarettes you have smoked in total over your lifetime: the number of packs smoked per day (20 cigarettes) is multiplied by the number of years smoked. So if you smoke one pack of cigarettes every day for one year, that equals one pack year. From 40 pack years onward, this is considered a very high risk for cancer.¹²

Smoking and its 15 types of cancer

Smoking contributes to the development of at least 15 different types of cancer:²

Smoking is the main cause of lung cancer, with almost 90% of all lung cancer cases being attributable to smoking.² People affected by throat and laryngeal cancer are also predominantly smokers. If you smoke, you are not only putting yourself at risk – passive smoking also increases the risk of cancer of the lungs, larynx, throat, breast, and cervix.²

Lungs after 20 years of smoking

What do your lungs look like after 20 years of smoking? After two decades of tobacco use, the lungs are rarely left without traces. Smoking leads to severe long-term damage such as chronic irritation of the bronchi and the tiny air sacs in the lungs (alveoli). As a result, pulmonary emphysema can develop, often also as part of COPD. In pulmonary emphysema, the many small air sacs in the lungs turn into larger cavities, which reduces the lung surface area available for oxygen exchange and leads to severe shortness of breath. The mucous membranes are also usually chronically inflamed after 20 years, and the fine cilia in the bronchi are destroyed or no longer functional. The lung tissue is chronically inflamed and overall lung function is impaired. 15 to 20 percent of all smokers suffer from COPD after 20 years,¹³ chronic bronchitis or asthma also often occur. The risk of lung cancer is also significantly increased after 20 years of smoking.

The longer you smoke, the more damage your lungs suffer.

What happens to lung cancer risk after quitting smoking

You can reduce your risk of lung cancer by quitting smoking. After ten smoke-free years, the risk is only half as high as it was during tobacco use.⁹ Overall, the earlier you quit, the greater the benefit for your health, but quitting smoking is worthwhile at any age. The risk of cardiovascular disease as well as mouth, throat, and urinary cancer decreases when you stop smoking, and you gain precious years of life. After quitting smoking, the cancer risk never quite returns to that of someone who has never smoked, but the earlier you stop, the closer you get.

40 years of smoking — effects on the body and life expectancy

Four decades of smoking leave their mark on the body; not just in the lungs, but systemically throughout the entire organism. But what does that specifically mean for your remaining life expectancy?

Life expectancy after 40 years of smoking

What do 40 years of smoking ultimately mean for your lifespan? Exact figures on life expectancy vary, but one thing is certain: smoking shortens your life. Roughly speaking, it means between 5 and 10 fewer years of life, although the range differs depending on the study. One source states that smokers aged 40 to 79 lose 12 years (women) to 13 years (men).¹⁴ Another source mentions that people who smoke more than 10 cigarettes a day lose an average of around 7 years (women) or 9 years (men) compared to non-smokers.³ A general rule of thumb is: 20 minutes less life per cigarette.¹⁴ It is consistently observed that the average reduction in lifespan is greater for men than for women.

The scale in numbers

In Germany, around 131,000 people die every year as a result of tobacco use. That Equals one in seven deaths in the country.¹ Currently, more than one in four adults in Germany smokes.¹ Also, 8% of adult non-smokers are regularly exposed to secondhand smoke and its harmful effects.³

What 40 years of smoking do to the body

After 40 years of smoking, the risk of fatal cardiovascular disease, stroke, and COPD increases dramatically.¹⁵ Many smokers also have to cope with conditions after 40 years of smoking such as atherosclerosis in multiple vascular systems, an increased risk of type 2 diabetes, periodontal disease (inflammation of the tooth-supporting structures), impaired kidney function, and a significantly increased cancer burden. Smoking causes almost 20% of all new cancer cases in Germany and is also the leading cause of COPD.⁹

The body tries to fight these health problems, but the body's own defense system (immune system) is weakened by years of smoking.

Smoker’s leg — when blood circulation in the legs fails

Smoking not only damages the coronary arteries and cerebral arteries, but all arteries in the body, including those that supply the legs. So-called PAD (peripheral arterial disease), commonly known as “smoker’s leg,” develops when deposits in the leg arteries restrict blood flow to such an extent that muscles and tissue are no longer supplied with enough oxygen. You can recognize smoker’s leg by cramp-like pain in the calves when walking, which eases at rest.

This symptom is called intermittent claudication (a recurring circulatory disorder) or window-shopping disease, because those affected often have to take short breaks. External signs of PAD are pale, cool, or bluish skin, poorly healing wounds, and dying tissue, known as necrosis. To counteract smoker’s leg, it is important to stop smoking immediately. In addition, a healthy diet and adjusted walking training or physiotherapy can help. In the late stage, open wounds and, in the worst case, amputations may occur.

Smoker’s lung — what smoking does to lung tissue

Chronic inflammation caused by tobacco smoke destroys lung tissue over the years. Tar and soot from cigarette smoke are deposited in the lungs, which is called anthracosis. The cilia in the bronchi, which normally move mucus and harmful substances out of the airways, are permanently damaged by the smoke and eventually destroyed. As a result, mucus can no longer be cleared from your lungs, germs have an easier time spreading, and breathing becomes more difficult. The main symptoms of smoker’s lung are smoker’s cough with phlegm and shortness of breath.

In the advanced stage, irreversible cavities form in the lung tissue, known as pulmonary emphysema. As a result, the lungs permanently lose surface area for oxygen exchange, which normally supplies the organs with oxygen. Here too, immediately giving up tobacco is considered the most important measure to stop the progression. Your lungs begin to clean themselves as soon as you stop smoking, and the cilia can recover. In addition, inhaled medications (so-called bronchodilators)¹⁶ and respiratory physiotherapy can help to reopen the airways.

Smoker’s cough — more than just an annoying symptom

Chronic cough in smokers is a warning signal from the body. Toxins from cigarette smoke permanently irritate the mucous membranes in the lungs. To protect them, the lungs produce thick mucus that binds the harmful substances. Because tobacco smoke destroys the cilia in the airways, coughing takes over the job of clearing the thick mucus and toxins from the lungs. A lot of mucus builds up, especially overnight, and needs to be cleared when you wake up. That is also why smoker’s cough is particularly severe in the morning.

Smoker’s cough can be an early sign of developing COPD or chronic bronchitis, which is why doctors take it seriously straight away, even though many affected people dismiss it as normal for a long time. To stop the progression of smoker’s cough, quitting smoking is recommended as the most important step.

Smoking during pregnancy & breastfeeding — risks for mother and child

Smoking during pregnancy harms your unborn child.

If you smoke cigarettes during pregnancy, the risk of pregnancy complications increases, and the substances contained in the smoke harm your unborn child. Toxic components of tobacco smoke such as nicotine, carbon monoxide, and hundreds of other compounds pass through the placenta into the embryo’s bloodstream and disrupt the natural development process. The functions of the placenta itself can also be impaired by these harmful substances. Smoking during pregnancy increases the risk of miscarriage, premature birth, stillbirth, and low birth weight.⁹

Because of an inadequate supply of oxygen and nutrients, the development of the fetal lung structure as well as the regulation of breathing and heartbeat are impaired. The child’s brain is also affected by these developmental disruptions.¹⁷ Even after birth, the newborn may remain limited in further development and later face a higher risk of respiratory diseases, cardiovascular diseases, and cancer.⁷ In addition, the risk of asthma and facial clefts (most commonly cleft lip and palate) is increased.¹⁷ Facial clefts are malformations in which tissue and bones in the face and mouth area do not fuse properly. Nicotine also passes into breast milk during breastfeeding and thus reaches the infant.

Quitting smoking during pregnancy is always worth it

Quitting smoking during pregnancy is worthwhile at any stage, even if several weeks have already passed. For your child’s development, every smoke-free day counts, and the risk of complications decreases with every month without tobacco. If you stop smoking before pregnancy, your child can be expected to have a normal birth weight. Quitting smoking during pregnancy can also lead to a normal birth weight, depending on the timing. However, if you do not stop smoking during pregnancy, the newborn is expected to have a birth weight reduced by 200–300 g.⁹

Passive smoking — health risks for non-smokers

Passive smoking also causes you to inhale the same harmful substances as active smoking.⁹ Around 8% of adult non-smokers in Germany are regularly exposed to secondhand smoke.³ Passive smoking increases the risk of lung cancer and stroke by 20–30%⁹ and the risk of cancer and cardiovascular disease by 35–40%.¹⁸ The risk of COPD also increases.⁷

In particular, very heavy smoke exposure over a longer period poses a major health risk. Children are especially at risk from secondhand smoke because they have a higher breathing rate and a less efficient detoxification system than adults.⁹ It can lead to developmental disorders and frequent illness. Children’s airways in particular are often affected by passive smoking, and health consequences can continue into adolescence and adulthood.⁹ Other effects of passive smoking on children include middle ear infections and health impairments affecting the lungs.⁹ So quitting smoking not only improves your own quality of life, but also that of the people around you.

Benefits of quitting smoking — what changes in the body

Why is it worth quitting smoking even after decades? Because your body can regenerate well into old age. That is exactly why quitting smoking is considered one of the most important protective measures against cardiovascular disease, heart attack, and stroke. So it is never too late to become smoke-free and benefit from the health advantages. The longer it has been since you quit smoking, the more noticeable your physical recovery will be. Feel free to read our article on quitting smoking.

How quickly does the body actually respond to giving up smoking? Faster than you might expect: Your sense of smell and taste begin to recover shortly after your last cigarette. After just a few days of nicotine withdrawal, you may notice an improvement in blood pressure and heart rate, and within a few weeks your mental health is strengthened as well.¹⁹ You can find out how quickly nicotine is broken down in the body in the article “How long does nicotine stay in the body?”.

In the longer term, after 5 smoke-free years, the risk of coronary heart disease and stroke is cut in half; after 10 years, the risk of lung cancer is only half as high; and after 15 years, the risk of developing COPD is also reduced by half.⁹

What if giving up cigarettes completely hasn’t worked out yet? For the transition, nicotine without the harmful tobacco smoke can help, such as in tobacco-free nicotine pouches (colloquially mostly referred to as Snus). There are numerous options you can use as an approach to gradually reduce your consumption. As a smoker, depending on your consumption, you’re generally best off with medium-strength Snus or stronger Snus.

shop medium-strength Snus shop stronger Snus

Nicotine Pouches with Nicotine Polacrilex are particularly suitable here — an active ingredient that releases nicotine especially slowly and is also used in nicotine gum. Here you’ll find a selection of Nicotine Pouches from the Helwit brand that use exactly this form of nicotine:

view all Helwit Snus

The addictive potential of nicotine remains and can lead to nicotine abuse; the crucial difference compared to smoking is the absence of tar, CO, and the more than 7,000 other toxic combustion by-products of cigarettes. If you’re interested in Snus, you’ll find all the key information in our guide “What is Snus?”. You can also read more in Smoke-free with Snus and Nicotine Pouches or browse more tips & strategies for quitting smoking here.