Smoking – what will happen to my body?

If you smoke, you’ve almost certainly heard friends and family nagging you to stop.

Even as you reach for a cigarette you know that smoking makes heart disease, stroke, cancer, chronic obstructive pulmonary disease (COPD), and other killers more likely.

Knowing about long-term risks though may not be enough to nudge you to quit, especially if you’re young. It can be hard to feel truly frightened by illnesses that may strike decades later.

So, if you carry on smoking, what could be the effects on your body?

Smoking is harmful because there are many ingredients in tobacco smoke that can harm your body.

The main health risks from smoking are lung cancer, heart disease and stroke. Smoking causes almost 90% of deaths from lung cancer, around 80% of deaths from COPD, and around 17% of deaths from heart disease.

However, smoking also affects other parts of the body too.

One study on smoking found that, on average, men who smoked throughout their lives died 10 years younger than those who had never smoked.

How smoking damages the body

As well as nicotine, there are more than 4,000 chemicals in tobacco smoke, of which many are poisons. At least 60 of these chemicals cause cancer.

Among some of the most dangerous components are:

Tar: When you breathe in tobacco smoke, some tar is deposited in the lungs. Your lungs are lined with tiny hairs that help ‘sweep’ germs and other things out of your lungs. It is harder for these hairs to move if your lungs are coated with tar.

The tar in cigarette smoke contains chemicals called carcinogens, which encourage the development of cancer cells in the body.

Carbon monoxide: Carbon monoxide binds itself to haemoglobin in the bloodstream and prevents it from carrying enough oxygen around the body. This means that someone who smokes is likely to get out of breath and get tired more easily.

Eventually, you can get a lung disease called chronic obstructive pulmonary disease (COPD). If you have this, it gets harder and harder to breathe.

Oxidant gases: Oxidant gases are gases that react with oxygen. They make bloodmore likely to clot, increasing the risk of heart attack or stroke.

Benzene: Exposure to benzene can cause cell damage at the genetic level, and has been linked to a range of different cancers, such as leukaemia and kidney cancer.

Benzene used to be added to petrol, but the practice was stopped because of health concerns.


One of the most dangerous effects of smoking is the increased risk of lung cancer.

Chemicals in tobacco smoke damage cells in the lungs and these then become cancer cells.

The chances of developing lung cancer are affected by how much an individual smokes and for how long.

A study published in 2011 estimated that over 80% of lung cancers in the UK in 2010 were caused by smoking. People who smoke today are 15 times more likely to die from lung cancer than life-long non-smokers.

Although the risk of dying from smoking is linked to how many cigarettes you smoke a day, duration of smoking is an even more important risk factor. So, smoking one pack of cigarettes a day for 40 years is more hazardous than smoking two packs a day for 20 years.

The good news is that stopping smoking has a very important bearing on reducing the risk of getting lung cancer. For instance, a man who has smoked throughout his life carries a 15.9% risk of dying from lung cancer by the time he is 75. For a man who stops smoking by the age of 50, this risk drops to 6% and is only 3% for someone who stops by the time they are 40.

It is not only lung cancer that can be caused by smoking. Other cancers include cancers of the mouth, lip, throat, bladder, kidney, stomach, liver, breast and cervix.

Heart disease

Smoking is a leading cause of heart disease and stroke – two of the main cardiovascular diseases. Smokers are almost twice as likely to have a heart attack compared with people who have never smoked.

Smoking damages the lining of your arteries. Some particles in smoke seem to help ‘bad’ cholesterol in the blood stick to blood vessels. This leads to a build up of fatty material, known as atheroma, which makes the arteries narrower. Narrowing of the arteries can lead to angina, a heart attack, or stroke.

The risk of a heart attack or stroke is also increased because the blood of a smoker is more likely to clot.

In addition:

  • Carbon monoxide in tobacco smoke reduces the amount of oxygen in the blood so that the heart needs to beat faster to supply the body with all its needs
  • Nicotine stimulates the body to produce adrenaline, which makes the heart beat faster. This raises blood pressure and increases the workload of the heart

Stopping smoking significantly decreases the risk of cardiovascular diseases.

Other diseases and conditions


People who smoke tend to look older than people who don’t .

This is because smoking changes skin, teeth and hair. For instance, a lack of oxygen and other nutrients reaching the skin damages its collagen and elastin, making skin look saggy and giving it an uneven colouring.

Sight loss

People who smoke have a much higher risk of developing problems with eyesight later in life. In fact, smoking doubles the chances of sight loss.

Tobacco smoke damages the tissues of the eye and increases the risk of developing age-related macular degeneration (AMD).

Smoking is also linked to the development of cataracts.

Oral health

Yellow teeth are an obvious cosmetic side-effect of smoking, but dental damage does not stop there. People who smoke are more likely to develop gum disease and persistent bad breath than those who don’t.


When a person inhales tobacco smoke, irritating substances settle in the moist lining of the airways. These substances can cause an attack in a person who has asthma.

This problem can be compounded because smoking could lead to permanent damage to the airways and can block the benefits of asthma medication.

Bone strength

People who smoke may develop brittle bones – a condition known as osteoporosis.

This is because smoking has a toxic effect on bone by stopping the construction cells from doing their work. The toxins upset the balance of hormones, such as oestrogen, that bones need to stay strong.


Smoking increases the chances of impotence dramatically for men by affecting blood vessels, including those that must dilate in order to achieve an erection.

A study of more than 2,000 men in the US aged between 40 and 79 found that those who smoked were more likely to experience erectile dysfunction that those who did not.

Early menopause

A study in the journal Menopause found a significant association between women who smoke and early menopause.

A review of 11 studies found that smokers experienced an onset of the menopause approximately one year earlier on average.

What smoking does to other people

Secondhand smoke exposure also harms babies and children, with an increased risk of respiratory infections, increased severity of asthma symptoms, more frequent occurrence of chronic coughs, phlegm and wheezing, and increased risk of cot death and glue ear.

It is estimated that globally 600,000 deaths a year are caused by secondhand smoke.

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